Post on 12-May-2022
CITY OF SHREVEPORT
WATER AND WASTEWATER DESIGN STANDARDS
Date: September, 2015
In association with: IMS Engineers + Hall Builders delMet Services + WilliamsCreativeGroup
By:
In association with: IMS Engineers + Hall Builders delMet Services + WilliamsCreativeGroup
By:
i
Table of Contents
Section 1 Introduction 1-1
1.1 Purpose of the Design Standards .................................................................................................... 1-1 1.2 Note to Design Engineer ..................................................................................................................... 1-1 1.3 Master Planning Documents ............................................................................................................. 1-2 1.4 Standard Specifications and Details ............................................................................................... 1-2 1.5 Design Standard References ............................................................................................................. 1-2
Section 2 Gravity Sewers 2-1
2.1 Wastewater Design Flow .................................................................................................................... 2-1 2.1.1 Design Flow .................................................................................................................................. 2-1 2.1.1.1 Per Capita Flows .......................................................................................................... 2-1 2.1.1.2 Peak Design Flow ........................................................................................................ 2-1 2.2 Gravity Sewer Design Calculations ................................................................................................. 2-2 2.3 Gravity Sewer Location ....................................................................................................................... 2-2 2.3.1 General ........................................................................................................................................... 2-2 2.3.2 Location in New Subdivisions .............................................................................................. 2-2 2.3.3 Location in Existing Streets ................................................................................................... 2-4 2.3.4 Public Lines in Commercial Developments .................................................................... 2-4 2.4 Gravity Sewer Pipe Separation Requirements .......................................................................... 2-4 2.4.1 Stormwater Drainage Ditch Crossings .............................................................................. 2-4 2.4.2 Protection of Water Supplies ................................................................................................ 2-4 2.4.3 Sanitary Sewers in Proximity with Storm Sewers ....................................................... 2-4 2.5 Gravity Sewer Pipe Size and Material ........................................................................................... 2-5 2.6 Gravity Sewer Cover ............................................................................................................................. 2-6 2.7 Minimum Slope and Pipe Velocities ............................................................................................... 2-7 2.8 Sewer Extensions ................................................................................................................................... 2-7 2.9 Sewer Service Connections ................................................................................................................ 2-7 2.10 Sewer Servitudes for Construction and Maintenance ......................................................... 2-8 2.11 Trenching and Bedding Requirements ...................................................................................... 2-9 2.11.1 Trenching ................................................................................................................................... 2-9 2.11.2 Bedding ....................................................................................................................................... 2-9
Section 3 Wastewater Manholes 3-1
3.1 Manhole Location .................................................................................................................................. 3-1 3.1.1 Manhole Spacing ........................................................................................................................ 3-1 3.2 Manhole Type .......................................................................................................................................... 3-2 3.2.1 Standard Manholes ................................................................................................................... 3-2 3.2.1.1 Pre-Cast Manholes ...................................................................................................... 3-2 3.2.1.2 Cast-In-Pace Manholes .............................................................................................. 3-2 3.2.2 Drop Manholes............................................................................................................................ 3-2 3.2.3 Vented Manholes ....................................................................................................................... 3-2 3.2.4 Discharge Manholes ................................................................................................................. 3-2 3.2.5 New Connections to Existing Manholes ........................................................................... 3-3 3.3 Manhole Diameter ................................................................................................................................. 3-3 3.4 Manhole Flow Channel ........................................................................................................................ 3-3
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ii
3.5 Manhole Castings ................................................................................................................................... 3-3 3.6 Manhole Access....................................................................................................................................... 3-3 3.7 Manhole Coatings................................................................................................................................... 3-4 3.8 Manhole Height Requirements under Various Conditions including
Flood Plains ............................................................................................................................................. 3-4 3.8.1 Height of Manhole Sidewall ................................................................................................... 3-4 3.8.2 Traffic and Street Locations .................................................................................................. 3-4 3.8.3 Finished Landscape Locations ............................................................................................. 3-4 3.8.4 Non-Finished Landscape Locations ................................................................................... 3-4 3.8.5 Non-Traffic Areas ...................................................................................................................... 3-4 3.8.6 Flood Plains .................................................................................................................................. 3-4
Section 4 Wastewater Force Mains 4-1
4.1 Design Period .......................................................................................................................................... 4-1 4.2 Wastewater Design Flows .................................................................................................................. 4-1 4.3 Design Calculations ............................................................................................................................... 4-1 4.3.1 Wastewater Force Mains ........................................................................................................ 4-1 4.3.1.1 Hydraulic Design of Force Mains .......................................................................... 4-1 4.3.1.2 Hydraulic Transients ................................................................................................. 4-4
4.3.1.3 Required Analysis for Hydrogen Sulfide (H2S) Generation
and Release ........................................................................................................................... 4-6 4.4 Location……. ..................................................................................................................................... ….....4-7 4.5 Thrust Restraint Systems ................................................................................................................... 4-7 4.6 Force Main Servitudes Both Construction and Maintenance .............................................. 4-7
Section 5 Trenchless Technologies 5-1
5.1 General .............................................................................................................................................. 5-1 5.2 Boring and Jacking................................................................................................................................. 5-1 5.2.1 Boring ............................................................................................................................................. 5-1 5.2.2 Pipe Jacking .................................................................................................................................. 5-2 5.3 Horizontal Directional Drilling ......................................................................................................... 5-3 5.3.1 HDD for Gravity Sewers .......................................................................................................... 5-3 5.3.2 HDD for Force mains ................................................................................................................ 5-4 5.3.3 Engineering Calculations ........................................................................................................ 5-4 5.3.3.1 Pullback Calculations ................................................................................................. 5-5 5.3.3.2 Long Term Operation Calculations ...................................................................... 5-6 5.3.3.3 Geotechnical .................................................................................................................. 5-7 5.3.3.4 Land Requirements .................................................................................................... 5-7 5.4 Pipe Bursting ........................................................................................................................................... 5-7 5.4.1 General ........................................................................................................................................... 5-7 5.4.2 Pipe Bursting Design ................................................................................................................ 5-8 5.4.3 Crushed Liner Process ............................................................................................................. 5-9 5.5 Cured in Place Pipe ................................................................................................................................ 5-9 5.5.1 General ........................................................................................................................................... 5-9 5.5.2 CIPP Guidelines......................................................................................................................... 5-10 5.5.2.1 Lateral Repairs ........................................................................................................... 5-11
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Section 6 Wastewater Lift Station Design 6-1
6.1 Wastewater Design Flows .................................................................................................................. 6-1 6.2 Number of Lift Station Pumps .......................................................................................................... 6-1 6.3 Wetwell Design ....................................................................................................................................... 6-1 6.3.1 Wetwell Volume for Variable Speed Pumping .............................................................. 6-1 6.3.2 Wetwell Volume for Constant Speed Pumping ............................................................. 6-2 6.3.3 Wet Well Appurtenances ........................................................................................................ 6-2 6.4 Lift Station Design Calculations and Procedures ...................................................................... 6-2 6.4.1 Pumps Selection ......................................................................................................................... 6-3 6.4.1.1 Pumps .............................................................................................................................. 6-3 6.4.1.2 System Head Curve ..................................................................................................... 6-3 6.4.1.3 Pump Curves ................................................................................................................. 6-4 6.4.2 Force Main .................................................................................................................................... 6-4 6.5 Submersible Sewage Pump Station ................................................................................................ 6-4 6.5.1 Construction ................................................................................................................................ 6-5 6.5.2 Wet Well Coatings ..................................................................................................................... 6-5 6.5.3 Removal of Submersible Pump ............................................................................................ 6-5 6.5.4 Electrical Equipment ................................................................................................................ 6-5 6.5.5 Valve Vaults .................................................................................................................................. 6-6 6.6 Dry Pit Pump Station ............................................................................................................................ 6-6 6.7 Valves for Pump Stations .................................................................................................................... 6-6 6.8 Air Release Valves ................................................................................................................................. 6-7 6.9 Emergency Bypass Connection ........................................................................................................ 6-7 6.10 Flowmeter. ............................................................................................................................................. 6-7 6.11 Pressure Gauges .................................................................................................................................. 6-7 6.12 Hoisting and Lifting Equipment .................................................................................................... 6-7 6.13 Odor Control.......................................................................................................................................... 6-8 6.14 Pump Station Emergency Operations ......................................................................................... 6-8 6.14.1 General ........................................................................................................................................ 6-8 6.15 Lift Station Controls ........................................................................................................................... 6-8 6.15.1 HMI Signals and Alarms ....................................................................................................... 6-9 6.15.2 Telemetry System ................................................................................................................... 6-9 6.15.2.1 General .......................................................................................................................... 6-9 6.15.2.2 Hardware ................................................................................................................... 6-10 6.15.2.3 Diagnostics ................................................................................................................ 6-10 6.15.2.4 Requirements of Power ....................................................................................... 6-10 6.15.2.5 Communications ..................................................................................................... 6-10 6.15.2.6 Radio System ............................................................................................................ 6-10 6.15.2.7 RTU Outputs to SCADA ......................................................................................... 6-11 6.16 Lift Station Siting and Access ....................................................................................................... 6-12
Section 7 Water Distribution Mains 7-1
7.1 Potable Water Design Flows ............................................................................................................. 7-1 7.1.1 Annual Average Daily Flow ................................................................................................... 7-1 7.1.2 Peak Daily Flow .......................................................................................................................... 7-1 7.1.3 Peak Hourly Flow ...................................................................................................................... 7-1 7.1.4 Water Main Sizing ..................................................................................................................... 7-1 7.2 Fire Flow .............................................................................................................................................. 7-1 7.2.1 Peak Flow ...................................................................................................................................... 7-1
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7.3 Transmissions Mains and Distribution Mains ........................................................................... 7-1 7.4 Water System Pressure ....................................................................................................................... 7-2 7.5 Water System Design Calculations ................................................................................................. 7-2 7.6 Water Main and Extension Location .............................................................................................. 7-3 7.6.1 Residential (service) Water Line ......................................................................................... 7-3 7.6.2 Normal Water Main Location ............................................................................................... 7-3 7.7 Water Main Separation Requirements ......................................................................................... 7-3 7.7.1 Horizontal Separation from Sanitary Sewer Mains ..................................................... 7-3 7.7.2 Vertical Separation .................................................................................................................... 7-3 7.7.3 Separation from Storm Drains and Other Utilities ...................................................... 7-3 7.7.4 Separation from Sewer Manholes ....................................................................................... 7-4 7.8 Water Main Diameters ......................................................................................................................... 7-4 7.9 Water Main Looping and Deadends ............................................................................................... 7-4 7.10 Potable Water Valves ......................................................................................................................... 7-5 7.11 Water Main Cover ............................................................................................................................... 7-5 7.12 Surface Water Crossings for Water Mains ................................................................................ 7-5 7.12.1 Above Grade .............................................................................................................................. 7-5 7.12.2 Below Grade .............................................................................................................................. 7-5 7.13 Roadway Crossings for Water Mains .......................................................................................... 7-6 7.14 Air Release Valves and Blow offs for Water Mains ............................................................... 7-6 7.14.1 Air Valves .................................................................................................................................... 7-6 7.14.2 Blow offs ..................................................................................................................................... 7-6 7.15 Disinfection Requirements .............................................................................................................. 7-6 7.16 Existing Water Mains ......................................................................................................................... 7-6 7.17 Thrust Restraints ................................................................................................................................ 7-6 7.18 Water Main Servitudes for Construction and Maintenance .............................................. 7-6 7.18.1 Servitude ..................................................................................................................................... 7-7 7.19 Service Connections ........................................................................................................................... 7-7 7.19.1 Service Connection Materials and Sizes ........................................................................ 7-7 7.20 Fire Code .............................................................................................................................................. 7-7 7.21 Plumbing Code ..................................................................................................................................... 7-7
Section 8 Fire Hydrants 8-1
8.1 General Location and Design Requirements .............................................................................. 8-1 8.2 Residential Subdivision Hydrant Location Standards ............................................................ 8-2 8.3 Commercial and Multi-Family Hydrant Location Standards ............................................... 8-2 8.4 Private Fire Hydrants ........................................................................................................................... 8-2 8.5 Maximum Fire Hydrant Spacing ...................................................................................................... 8-3 8.6 Fire Hydrant Relocations .................................................................................................................... 8-3
Section 9 Line Valves, Air Relief Valves and Blow-off Chambers 9-1
9.1 Line Valves .............................................................................................................................................. 9-1 9.1.1 Isolation Valves .......................................................................................................................... 9-1 9.1.2 Pressure Reducing Valves ...................................................................................................... 9-2 9.2 Air Valves .............................................................................................................................................. 9-2 9.2.1 Requirements .............................................................................................................................. 9-2 9.2.2 Types ............................................................................................................................................... 9-2 9.2.3 Location and Sizing ................................................................................................................... 9-3 9.2 Blow-off Chambers ................................................................................................................................ 9-3
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9.3.1 Requirements .............................................................................................................................. 9-3 9.3.2 Locations ....................................................................................................................................... 9-3 9.3.3 Sizing ............................................................................................................................................... 9-3
Section 10 Water Meters 10-1
10.1 General Requirements .................................................................................................................... 10-1 10.2 Definitions ............................................................................................................................................ 10-1 10.2.1 Residential Meter .................................................................................................................. 10-1 10.2.2 Non-Residential Meter ........................................................................................................ 10-1 10.2.3 Irrigation Meter ..................................................................................................................... 10-1 10.2.4 Master Meter ........................................................................................................................... 10-1 10.2.5 Sub-Meter ................................................................................................................................. 10-1 10.2.6 Deduct Meter (Private Meter) ......................................................................................... 10-1 10.2.7 Temporary Meters (Fire Hydrant Meter) ................................................................... 10-1 10.2.8 Wholesale Meter (Customer City Meter) .................................................................... 10-2 10.3 Design Data .......................................................................................................................................... 10-2 10.3.1 Domestic Water Demand ................................................................................................... 10-2 10.3.1.1 Combined Fixture Value ...................................................................................... 10-2 10.3.1.2 Peak Domestic Demand ....................................................................................... 10-3 10.3.1.3 Pressure Adjustment ............................................................................................. 10-4 10.3.2 Irrigation Water Demand .................................................................................................. 10-4 10.3.3 Mechanical Demand ............................................................................................................. 10-4 10.3.4 Fire Demand ............................................................................................................................ 10-4 10.4 Meter Classification .......................................................................................................................... 10-5 10.4.1 Positive Displacement (PD) Meter ................................................................................. 10-5 10.4.2 Non-Displacement Meter ................................................................................................... 10-5 10.4.3 Compound Meter .................................................................................................................. 10-5 10.4.4 General Use Recommendations ...................................................................................... 10-5 10.5 Meter Service ...................................................................................................................................... 10-6 10.5.1 Domestic Service Meters.................................................................................................... 10-6 10.5.2 Large Domestic Service Meters ....................................................................................... 10-6 10.5.3 Fire Service Detector Check Device ............................................................................... 10-6 10.5.4 Irrigation Service Meter ..................................................................................................... 10-6 10.5.5 Combined Water and Fire Services Meters ................................................................ 10-6 10.5.5.1 Small Combined Water and Fire Service Meter(s) ................................... 10-6 10.5.5.2 Large Combined Water and Fire Service Meter(s) ................................... 10-6 10.6 Location and Installation ............................................................................................................... 10-6 10.6.1 Accessibility............................................................................................................................. 10-6 10.6.2 Minimum Length of Unobstructed Pipe ...................................................................... 10-7 10.6.3 Miscellaneous Items ............................................................................................................ 10-7 10.7 Meter Box and Vault ......................................................................................................................... 10-7 10.7.1 General ...................................................................................................................................... 10-7 10.7.2 Meter Box ................................................................................................................................. 10-8 10.7.3 Meter Vault .............................................................................................................................. 10-8 10.8 Special Design Considerations ..................................................................................................... 10-8 10.8.1 Deduct Meter .......................................................................................................................... 10-8 10.8.1.1 General ........................................................................................................................ 10-8 10.8.1.2 Typical Configurations ......................................................................................... 10-8 10.8.2 Wholesale Meter.................................................................................................................... 10-8 10.8.2.1 General ........................................................................................................................ 10-8
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10.8.2.2 Typical Configurations ......................................................................................... 10-8
Section 11 Cross Connection Protection 11-1
11.1 Special Design Considerations ..................................................................................................... 11-1 11.2 Backflow Prevention Devices ....................................................................................................... 11-1 11.3 Backflow Prevention for Commercial, Industrial, and Multi Family Residences ................................................................................................................ 11-1 11.4 Backflow Prevention for Irrigation System ............................................................................ 11-2 11.5 Locations for Backflow Prevention Devices ........................................................................... 11-2 11.5.1 Locations .................................................................................................................................. 11-2 11.5.1.1 Fire Sprinkler Systems ......................................................................................... 11-2 11.5.1.2 Irrigation / Lawn Sprinkler Systems .............................................................. 11-2 11.5.1.3 Auxiliary Sources .................................................................................................... 11-2 11.5.1.4 Wastewater Treatment Plants, Pump Stations and Water Reduction Facilities ................................................................................................... 11-2 11.5.1.5 Water Treatment Plants ...................................................................................... 11-3 11.5.1.6 Plating and Chemical Companies ..................................................................... 11-3 11.5.1.7 Other Locations ....................................................................................................... 11-3 11.6 Plumbing Code ................................................................................................................................... 11-3
Section 12 Pipe Aerial Crossings 12-1
12.1 General Considerations .................................................................................................................. 12-1 12.2 Design Considerations .................................................................................................................... 12-1
Section 13 Pipe Stream Crossings 13-1
13.1 Design Considerations .................................................................................................................... 13-1 13.2 Material and Appurtenances ........................................................................................................ 13-2 13.3 Erosion Control .................................................................................................................................. 13-2
List of Figures Figure 2-1 Sewer Line Location – Guidance Schematic ................................................................................... 2-3 Figure 5-1 Horizontal Directional Drilling Pullback ......................................................................................... 5-6 Figure 7-1 Cul-De-Sac Dead Ends ............................................................................................................................. 7-4 Figure 10-1 Water Flow Demand per Fixture Value – Low Range ........................................................... 10-3 Figure 10-2 Water Flow Demand per Fixture Value – High Range ........................................................... 10-3
List of Tables Table 1 1 Minimum Design Life ................................................................................................................................. 1-1 Table 2-1 Gravity Sewer Cover .................................................................................................................................. 2-6 Table 2-2 Minimum and Maximum Slopes for Gravity Sanitary Sewer .................................................... 2-7 Table 2-3 Minimum Sewer Servitude Widths ...................................................................................................... 2-8 Table 3-1 Diameter of Manholes ............................................................................................................................... 3-3 Table 5-1 Casing Sizes .............................................................................................................................................. 5-2 Table 5-2 Pipe Bursting Design ................................................................................................................................. 5-8 Table 5-3 CIPP Method Limitations ....................................................................................................................... 5-10 Table 6-1 Lift Station Size Classification ................................................................................................................ 6-8
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Table 6-2 Lift Station Control Elements ................................................................................................................. 6-9 Table 6-3 Lift Station HMI Signals and Alarms ................................................................................................... 6-9 Table 6-4 Lift Station RTU Outputs ........................................................................................................................ 6-11 Table 8-1 Fire Hydrant Spacing ................................................................................................................................. 8-3 Table 9-1 Line Valve Spacing ...................................................................................................................................... 9-1 Table 10-1 Recommended Fixture Value ............................................................................................................ 10-2 Table 10-2 Pressure Adjustment Factors ............................................................................................................ 10-4 Table 10-3 Recommended Use of Various Water Meters General Category ........................................ 10-5 Table 10-4 Required Minimum Straight Unobstructed Pipe Length for Water Meter ..................... 10-7
Appendices Appendix A – Consultant Rating Form
Appendix B – Plan Review Checklist
Appendix C – References
Appendix D – Design Phases
1-1
Section 1
Introduction
1.1 Purpose of the Design Standards The purpose of this manual is to provide guidelines and minimum design criteria for the design of
water and wastewater systems for the City of Shreveport (the City) as part of:
Consent Decree Program Projects
Capital Improvement or Bond Projects
Private Development Projects
In the case of Private Development Projects it is assumed that the infrastructure constructed will be
transferred and donated to the City for operation and maintenance. The manual also applies to
existing systems being expanded, modified, upgraded and rehabilitated, as well as construction of new
facilities. These standards are based on commonly practiced engineering principles, pertinent
textbooks and literature. While these standards establish the minimum design requirements, it is not
intended to substitute for any professional engineering judgment by the Design Engineer who will
assume ultimate responsibility for selection, reference and appropriate application of this manual.
Any exceptions to these standards or variation from these standards shall be submitted in writing
with detailed justification, and calculations to the City’s Engineering and Environmental Services
(EES) Department, and where applicable the Louisiana Department of Health and Hospitals. All units
of measurement used in this manual are United States standard units unless otherwise noted.
1.2 Note to Design Engineer The Design Engineer shall familiarize themselves with the contents of this manual, including the
appendices. These appendices include the City’s Consultant Rating Form (Appendix A), an updated
plan review checklist (Appendix B), additional references (Appendix C), and an overview of design
phases (Appendix D). The Design Engineer shall update their Master/Guide specifications and/or
pertient City specifications to suit the needs of each individual project. The Design Engineer shall
abide by these requirements in completing design.
Minimum design life required by the City, for different types of installations are stated below in Table
1-1.
Table 1-1 Minimum Design Life
Type of Installation Minimum Design Life (years)
Pipes 50 years
Mechanical Equipment 20 years
Electrical Equipment* 20 years
Variable Frequency Drives 15 years
Structural Installations 50 years
*- Excluding Variable Frequency Drives.
Section 1 Introduction
1-2
1.3 Master Planning Documents The City’s Wastewater System Master Plan will include a computerized hydraulic model (Infoworks CS
by Innovyze). This model will be able to provide design flows for each of the City’s Sanitary Sewer
Service Area for both Wet weather and Dry Weather conditions. These flows will be the basis for
sewer design as described below in Section 2.1, Wastewater Design Flows. In the areas where the
flows are not included in the model, the sewer design shall be based on population estimates as
described in Section 2.1.
The Shreveport-Caddo Master Plan 2030 provides additional information on proposed land use and
future facilities to serve the City of Shreveport. An additional planning document that should be
consulted is the Caddo Parish Water Master Plan dated 2012. This document examines the potential
expansion of both Water and sewer into areas of Caddo Parish adjacent to the City of Shreveport.
1.4 Standard Specifications and Details The City of Shreveport has a set of standard specifications and details for Water and Wastewater
Projects. These specifications provide the level of expectation of quality for the construction of water
and wastewater projects. However, the standard specifications and details may not apply to all
projects, and therefore the Design Engineer is advised to review these standard documents, and
update their specifications and/or details as it applies to the project. The Design Engineer can request
the latest version of these documents from the City’s EES Department.
1.5 Design Standard References The Design Engineer shall prepare design documents that conform to the Consent Decree Program (if
applicable) and the adopted version of all applicable local, state, and federal regulations. The Design
Engineer shall verify the applicable codes and standards and their editions shall be verified at the time
of design. These Standards and references include but are not limited to:
ACI 318, Building Code Requirements for Structural Concrete
ACI 530, Building Code Requirements for Concrete Masonry Structures
Air Moving and Conditioning Association (AMCA)
AISC 341Seismic Provisions for Structural Steel Buildings, Including Supplement No. 1
AISC Manual of Steel Construction
AISC Specifications for Structural Joints Using ASTM A 325 or A 490 Bolts
AISI Specifications for the Design of Light-gauge, Cold-formed Steel Structural Members
Aluminum Association Specifications for Aluminum Structures
American Concrete Institute (ACI) 350, Code Requirements for Environmental Engineering
Concrete Structures
American Institute for Steel Construction (AISC), Steel Construction Manual
American National Standards Institute (ANSI) /Hydraulic Institute Standards
Section 1 Introduction
1-3
American Society for Testing and Materials (ASTM)
American Society of Civil Engineers (ASCE) and Water Pollution Control Federation, ASCE
Manual and Report on Engineering Practice No. 60 - Gravity Sanitary Sewer Design and
Construction
American Society of Heating Refrigerating and Air Conditioning Engineers (ASHRAE)
American Society of Mechanical Engineers (ASME)
American Water Works Association (AWWA) Standards
American Welding Society Structural Welding Code AWS D1.1
Americans with Disabilities Act (ADA)
ANSI/AWWA D110, Wire- and Strand-Wound, Circular, Pre-stressed Concrete Water Tanks
ASCE 7, Minimum Design Loads for Buildings and Other Structures
ASCE and Water Pollution Control Federation, ASCE Manual and Report on Engineering Practice
No. 76 – Design of Municipal Wastewater Treatment Plants
Associated Air Balance Council (AABC)
Brick Industry Association
City of Shreveport, Standard Specifications for Public Works Construction
City of Shreveport, Standard Details
City of Shreveport, Stormwater Guidelines
City of Shreveport, Unified Development Code
Code of Ordinances, City of Shreveport, Louisiana
Design of Wastewater and Storm water Pumping Stations, Manual of Practice FD-4, Water
Environment Federation (WEF)
ICC/ANSI 117.1 - Useable Buildings and Facilities
IEEE 519 Recommended Practices for Harmonic Control in Electrical Power Systems
IEEE Standard 142 for Recommended Practices for Grounding
Institute of Electrical and Electronics Engineers (IEEE)
International Building Code (IBC)
International Energy Conservation Code
International Fire Code (IFC)
Section 1 Introduction
1-4
International Fuel Gas Code (IFGC)
International Mechanical Code (IMC)
International Society of Automation (ISA)
Louisiana Department of Environmental Quality (LADEQ)
Louisiana Department of Health and Hospitals, Office of Public Health (OPH)
Louisiana Office of State Fire Marshal’s codes
Louisiana Standards For Waterworks and Construction
Louisiana State Plumbing Code
National Association of Architectural Metal Manufacturers: Metal Bar Grating Manual and
Heavy Duty Metal Bar Grating Manual
National Electrical Manufacturers Association (NEMA)
NFPA 1 Fire Code
NFPA 101 Life Safety Code
NFPA 70, National Electrical Code
NFPA 820 Standard for Fire Protection in Wastewater Treatment and Collection Facilities
Occupational Safety and Health Act (OSHA)
Pumping Station Design, Latest Edition by Robert L. Sanks
Railroad Standards and Permit Conditions
Sheet Metal and Air Conditioning Contractors National Association (SMACNA)
State of Louisiana Department of Transportation (DOT), Standard Specifications for Roads and
Bridges (latest edition)
Steel Joist Institute Standard Specifications
Ten States Standards, Recommended Standards for Wastewater Facilities, Great Lakes - Upper
Mississippi River Board of State and Provincial Public Health and Environmental Engineers
Uni-Bell Plastic Pipe Association, Handbook of PVC Pipe, Design and Construction
United States Environmental Protection Agency (EPA)
WEF, MOP No. 8, Design of Wastewater Treatment Facilities
Additional references can be found in Appendix C.
2-1
Section 2
Gravity Sewers
The following design standards are provided as guidelines only. The Design Engineer is responsible
for the design of gravity sewers (includes submains, trunk mains and interceptors), and evaluating all
requirements on a case by case basis. See Section 1.1 regarding exceptions.
2.1 Wastewater Design Flow All sanitary sewers shall be designed to carry the estimated wet weather design peak flow from the
area that ultimately contributes to the sanitary sewer. The City will provide design flow information,
if available, to the Design Engineer based on the hydraulic model. It shall be the Design Engineer’s
responsibility to review this data, and based on detailed survey information and field review of the
project collection system, note any potential inconsistencies in the provided flow data and present
them to the City. The Design Engineer is responsible for submitting written requests to the City for
confirmation of the selected alternative and recommendations based on the hydraulic model. In the
areas where the flows are not included in the hydraulic model, the sewer design shall be based on
population estimates as described below.
2.1.1 Design Flow 2.1.1.1 Per Capita Flows
New sewer system shall be designed on the basis of population estimates for the project area and the
average daily per capita flow. The estimated population shall be multiplied by the estimated per capita
wastewater contribution to obtain the average daily flow estimations. The average per capita
wastewater flow plus groundwater infiltration in Louisiana is 150 gpcd (Guidance for Evaluating
Infiltration and Inflow for State Revolving Fund Projects). Different figures for per capita wastewater
flow may be used if supported by flow measurement and census data.
Commercial, industrial and institutional flows may vary significantly depending on the industry type,
size, and operational techniques, among other factors. Such flows shall be estimated based on historic
water usage records, flow measurements or design standards acceptable to the City. These flows shall
be included as necessary for estimating the per capita flow from the project.
2.1.1.2 Peak Design Flow
When designing sanitary sewers, the average daily flow shall be peaked using the ratio of peak hourly
flow to design average flow. If field data, data from models or studies is not readily available, the Peak
Flow factor (PF) can be obtained using the following relationship:
( )
(
)
Where P = the population in thousands
Peak Design Flow (PDF) shall be obtained by multiplying the sum of average daily
flows generated from residential and commercial areas by their respective PF.
Section 2 Gravity Sewers
2-2
( )
( )
Peak flow includes both peak daily flow and rainfall-dependent infiltration/inflow and
groundwater infiltration.
2.2 Gravity Sewer Design Calculations The Designer shall use Manning’s Equation for hydraulic design, and sizing of gravity sewers. A
roughness coefficient “n” value of 0.013 should be used. This value compensates for offset joints, poor
alignment, grade settlement, sediment deposition, and the effect of slime and grease build-up in
sanitary sewers.
Manning’s Equation:
(
)
Where:
Q is the discharge (cubic feet per second, cfs)
A is the cross sectional area of flow (square feet, ft²);
n is the roughness coefficient, assume n to be 0.013 for all pipe materials;
R is the hydraulic radius, which is the area of flow over the wetted perimeter (ft.);
S is the slope (feet/feet).
And:
(
)
Where:
V is the velocity, feet per second.
2.3 Gravity Sewer Location 2.3.1 General All sanitary sewers shall be placed in public street rights-of-ways or within servitudes.
2.3.2 Location in New Subdivisions Public sewer lines shall be located in public right-of-ways or in a dedicated servitude that is at least
20 feet wide. See Table 2-3 in this section for more details. Any exceptions to this shall be submitted to
the City for approval.
Section 2 Gravity Sewers
2-3
Prior to paving of streets or sidewalks, sewer mains and services shall be in place, or the developer
shall provide necessary casing for such utilities. Backlot or sidelot servitudes will not be allowed. See
Figure 2-1 (below) for a guidance schematic.
Figure 2-1 Sewer Line Location – Guidance Schematic
Notes:
1) This drawing is normally for streets oriented East-West. Flip drawing 90 degrees counter-clockwise for streets oriented North-South.
2) Water and sewer lines shall be located in public Right-Of-Ways. 3) Minimize servitude overlap on private property lines. 4) Dedicated servitudes on private property allowed only if there are limitations in using the
public Right-Of-Way. Design Engineer shall submit written justification for City review. 5) Gravity sewer shall be located normally on South (for East-West streets) or on the East (for
North-South streets) from the centerline of the paved street. 6) Do not locate sewer/water service lines beneath private walkways or driveways. 7) Maintain five (5’) feet separation (minimum) from existing/proposed utilities, poles, and
other structures. 8) Locate gravity sewers and water mains at the center of the servitude. 9) Water mains shall be located on the opposide side of the street from gravity sewers.
Section 2 Gravity Sewers
2-4
2.3.3 Location in Existing Streets When sanitary sewers are to be installed in an existing street, factors such as curbs, gutters, sidewalks,
traffic conditions, traffic lane condition, pavement conditions, future street improvement plans, and
existing utilities shall be considered. As outlined in the City’s Ordinance (78-102), no existing
pavement shall be cut without the approval of the City Engineer. When sanitary sewers are extended
for developments, they shall be extended to the furthest property line to facilitate future expansion.
2.3.4 Public Lines in Commercial Developments The Design Engineer shall locate all sewers within City right-of-ways.
2.4 Gravity Sewer Pipe Separation Requirements 2.4.1 Stormwater Drainage Ditch Crossings Whenever applicable, sanitary sewers crossing over drainage ditch(es) shall be pressure tested from
manhole to manhole to confirm 100 percent water tightness. Minimum pipeline cover under drainage
ditches shall be five (5) feet. In instances where the specified cover is not achievable, a concrete
encasement shall be used. The Design Engineer shall also meet the requirements stated in Section 13
of this manual.
2.4.2 Protection of Water Supplies There shall be no physical connections between a public or private water supply system and a sanitary
sewer or its appurtenances, that would permit the passage of any wastewater into the potable water
supply. The Design Engineer shall design sanitary sewers to be installed at least 10 feet horizontally,
measured edge-to-edge, from any existing or proposed water line. In cases where it is not practical to
maintain a 10-foot separation, the City may allow deviation (upon review) on a case-by-case basis if
supported by data from the Design Engineer. Such deviations may allow installation of the sewer
closer to a water main, provided that the following conditions exist:
Water main is in a separate trench or on an undisturbed earth shelf located to one side of the
sewer
Water main is at an elevation such that the bottom of the main is at least 18 inches above the
top of the sewer
Sanitary sewers crossing water mains shall be designed to provide a minimum vertical separation
distance of 18 inches between the outside of the water main and the outside of the sewer. This shall be
the case where the water main is either above or below the sewer. The crossing shall be designed so
that the sewer joints will be equidistant and as far as possible from the water main joints. All water
mains crossing sanitary sewers shall be encased in concrete. Normally, water mains shall be located
above sanitary sewers. When it is impossible to obtain proper horizontal and vertical separation as
stipulated above, both the water main and the sewer shall be restrained with slip-on joint or
mechanical joint pipe complying with the public water supply design standards, and shall be pressure
tested to 150 psi to verify water tightness before backfilling.
2.4.3 Sanitary Sewers in Proximity with Storm Sewers The Design Engineer shall provide a minimum horizontal separation greater than or equal to 3 feet
(outside-to-outside) for new parallel sewer construction near storm sewers.
Section 2 Gravity Sewers
2-5
The Design Engineer shall provide a minimum vertical separation greater than or equal to 12 inches
for new sewer crossings over storm sewers. When horizontal separation is less than 3 feet, the
minimum sanitary sewer pipe material specification shall be AWWA C900 or AWWA C905 (DR 18)
PVC pipe or pressure class 150 Ductile Iron Pipe (DIP)with Protecto 401 coating from manhole to
manhole. When vertical separation is less than one foot, a neoprene pad shall be placed between the
two pipes. Any exceptions to this standard shall be submitted for City approval.
Storm sewers shall not be connected to sanitary sewers. Storm sewers that are known or are found to
be connected to sanitary sewers, during construction activities, field activities, or surveying, shall be
disconnected and capped.
2.5 Gravity Sewer Pipe Size and Material All sewers shall be designed to prevent damage from superimposed live and dead loads. Proper
allowance for loads on the sewer shall be made for soil and potential groundwater conditions, as well
as the width and depth of the trench. Refer to ASTM D2321 or C12 when appropriate. Owing to ease of
maintenance, minimum size for gravity sewers is set at 8 inches diameter. Gravity sewers above 48
inches in diameter are considered special design; the design engineer shall consider relevant
geotechnical information, trench type, and soil corrosivity in completing design for gravity sewers
above 48 inches in diameter. Furnish in the Design Criteria report to the City, relevant design
calculations, and justifications for gravity sewers of size 48 inches and above.
Pipe material shall not change from manhole to manhole. In addition, gravity sewer pipe material shall
conform to the City’s Standrad Specification Section 209.
Polyvinyl Chloride Pipe (PVC) is preferred for gravity sewers up to 48 inches in diameter.
Sizes 8 inches to 15 inches shall be PVC (ASTM D3034, DR 35 minimum) solid wall pipe. Sizes
18 inches and above shall be PVC (ASTM F679, PS 46 minimum) solid wall pipe.
Certa-Flo gravity sewer piping may be considered for restrained PVC pipe applications up to
12 inches in diameter.
Where pipe depth is greater than 20 feet, DR 26 (minimum) solid wall pipe shall be provided.
Closed Profile Wall PVC Piping is preferred for gravity sewers over 48 inches in diameter.
However, the Design Engineer shall perform all relevant calculations (as stated above) to
justify the use of closed profile wall PVC piping.
Closed profile wall PVC piping shall meet the requirements of ASTM F1803, and shall be rated
for a minimum pipe stiffness of 46 psi.
Ductile Iron Pipe (DIP) is permitted only in instances where it is not practical to use PVC or closed
profile wall PVC piping or it is mandated by an utility owner (ex: petrochemical pipe crossings).
Design Engineer shall submit a detailed written justification for selecting DIP over PVC and closed
profile wall PVC piping.
Section 2 Gravity Sewers
2-6
Ductile iron pipes, when used, shall be of the pressure class listed below.
Pipe Sizes (inches) Min. Pressure Class (psi)
8-12 350
14-20 250
24 200
30-64 150
Smaller DIP shall be considered for shallow bury, road crossings, and creek crossings
(encasement may be required). The Design Engineer shall use the recommendations for
encasement found in Section 7 and Section 13 as applicable.
See construction requirements for encasement in the applicable sections of the City’s Standard
Specification Sections for Roadways, Excavation and Backfill, and applicable Standard Plans.
Where special conditions warrant, additional details may be shown on the project plans, or
the Special Provisions may include such special requirements.
High Density Polyethylene Pipe (HDPE) and fusible PVC
HDPE and fusible PVC pipe shall only be used for trenchless design and construction. HDPE
piping shall be per the City’s Standard Specifications with heat fusion welded joints. Any
exceptions to this shall be submitted in writing for the City’s review and approval.
For piping above 64 inches in diameter, the Design Engineer shall consult the City Engineer
regarding their preference for pipe materials. Deflection at joints shall be limited to 50% of
the manufacturer’s recommendations.
2.6 Gravity Sewer Cover Table 2-1 lists the minimum cover requirements for gravity sewers. An unimproved area occurs when
there is just natural ground with no permanent pavement or curb and gutter. An improved area
occurs where there is permanent paving with base, curb and gutter and other ground construction.
The depth of cover is determined from the top of pipe to the finished ground surface. The Design
Engineer must consider the depth requirement to service adjacent properties to the sewer. The
Design Engineer shall also consider possible buoyancy of the sewers due to high groundwater
conditions and prevent possible flotation of the pipe.
In cases where the Design Engineer is unable to maintain minimum cover, these locations shall be
designed to handle the possible loads that the sewer may be subjected to. Also, the Design Engineer
shall contact the owner of the Highway or Railroad for additional requirements.
Table 2-1 Gravity Sewer Cover
Size of Sewer Minimum Depth In Feet
Unimproved1 Improved Highway/Railroad
≤18 inches 6 5 6
>20 inches 7 6 6
1 – Design Engineer to consider future improvements and grades in consultation with the City Engineer when designing gravity sewers in unimproved
areas.
Section 2 Gravity Sewers
2-7
2.7 Minimum Slope and Pipe Velocities The Design Engineer shall design all sanitary collector and trunk sewers to provide a minimum
velocity of 2 feet per second (fps) when flowing full (for pipes 42-inches in diameter and less), or a
minimum velocity of 3 fps when flowing full (for pipes greater than 42-inches in diameter), and a
maximum velocity of 10 fps when flowing full, as calculated using Manning’s equation.
Table 2-2 presents the minimum and maximum slopes that shall be used as design criteria. Velocity
shall be calculated at the design flow.
Table 2-2 Minimum and Maximum Slopes for Gravity Sanitary Sewer
Sewer Pipe Diameter
Inches
Minimum Slope
%
Maximum Slope
%
8 0.4 8.34
10 0.28 6.20
12 0.22 4.86
14 0.17 4.0
15 0.15 3.61
16 0.14 3.31
18 0.12 2.83
21 0.10 2.30
24 0.08 1.93
27 0.067 1.65
30 0.058 1.43
36 0.046 1.12
42 0.037 0.91
If the Design Engineer prefers to use minimum slopes less than those indicated, it shall be submitted
to the City in writing with justification. Such cases may be approved by the City on a case-by-case
basis.
Similarly, velocities greater than 10 fps will be considered on a case-by-case basis, with proper
consideration to pipe material, abrasive characteristics of the wastewater, turbulence, thrust at
changes of direction, and protection against pipe and bedding displacement.
2.8 Sewer Extensions The Design Engineer shall calculate or obtain from the City (if available) the design flow rates for
sewer extensions. The service areas for sewer extensions shall be clearly identified and coordinated
with the Wastewater Master Plan to see if additional areas for the sewer extension will be required.
2.9 Sewer Service Connections The Design Engineer shall design laterals to be replaced up to the property line or permanent
servitude line with minimum 4-inch PVC (SDR 35) service laterals, and a minimum slope of one
percent.
Section 2 Gravity Sewers
2-8
A new PVC cleanout on or within the property line, with a tee/wye shall be provided per Louisiana
State Plumbing Codes. Service laterals connected to DIP shall use ductile iron wyes with Protecto 401
Ceramic Epoxy lining.
All existing sewer service locations shall be replaced, and new service connections shall be designed to
service both present and future connection requirements. The Design Engineer shall review the
requirements for service connections as stated in the City Standard Specification 2000 and Standard
Plan 2200-10.
2.10 Sewer Servitudes for Construction and Maintenance The Design Engineer shall place all new or rehabilitated sewers within existing City right-of-ways or
servitudes. If it is determined (and approved by the City) that the project will be performed outside of
existing right-of-way or existing servitudes, then it will be necessary to obtain a new servitude.
The Design Engineer shall request a surveyor to prepare a legal description for the required servitude.
This request shall include, but not be limited to, the following information:
Type of Servitude: Permanent or temporary/construction
Purpose of Servitude: Water and/or wastewater servitude
Project Schedule: Planned advertisement and construction date
Location Map: A map showing location of servitude with coordinates and dimensions.
Verification that a minimum of 25 feet of vertical clearance above the servitude is available to
permit the operation of backhoes and trackhoes. Any exception to this shall be approved by the
City.
When placed in servitudes owned by other entities (ex: Department of Transportation and
Development or Kansas City Souther Rail Road), design shall be in conformance with the
entity’s requirements.
Table 2-3 (below) lists the recommended minimum width requirements for sewer servitudes.
Table 2-3 Minimum Sewer Servitude Widths
Size of Sewer
Inches
Depth of Sewer
Feet
Servitude Width
Feet
8-12 ≤ 8
>8
20
25
15-24 ≤ 8
>8
25
35
30-66 ≤ 8
>8
40
50
72 and larger ≤ 8
>8
60
70
Section 2 Gravity Sewers
2-9
2.11 Trenching and Bedding Requirements See Construction requirements for trench excavation, bedding and backfill in the applicable sections of
the Specification Section 1002 Excavation and Backfill and as shown in Standard Plan 2000-1. Where
special conditions warrant, additional details may be shown on the project plans.
2.11.1 Trenching The width of the trench shall be ample to allow the pipe to be laid and jointed properly and to allow
the bedding and haunching to be placed and compacted to adequately support the pipe. The trench
sides shall be kept as nearly vertical as possible. When wider trenches are specified, appropriate
bedding class and pipe strength shall be used.
2.11.2 Bedding Bedding shall be designed in accordance with:
Rigid Pipe: Bedding equal to Classes A, B, or C, or crushed stone as described in ASTM C12
Flexible Pipe: Material equal to Classes I, II, or III, as described in ASTM D2321
Section 2 Gravity Sewers
2-10
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3-1
Section 3
Wastewater Manholes
3.1 Manhole Location Manholes shall be installed at the following locations:
Changes of grade or slope.
Changes of pipe size.
Changes of horizontal or vertical alignment.
Changes in pipe material.
Pipe intersections except with service connections less than 6-inches in diameter.
Change in flow direction.
The end of each public sewer line.
The terminus of dead-end sewers.
Discharge of private pump station force main.
Manholes shall not be placed in any of the following locations:
Inaccessible areas.
In the flow line of an existing creek or drainage area.
In sidewalks, crosswalks, or pedestrian ramps.
In driveways.
In gutters or curb lines.
In freeway ramps or lanes.
Between railroad tracks (manholes within a railroad right-of-way shall be located a minimum of
15 feet from track bed and in accordance with the requirements of the railroad.
Within 15 feet of any structure, including subterranean or overhead structures.
Furthermore, when locating manholes in the street or paving, the Engineer shall locate them such that
they are outside of the wheel-path as much as possible.
3.1.1 Manhole Spacing Manhole spacing shall be a maximum center to center distance of 400 feet for collection system piping
up to 15-inches in diameter. For sewers 18-inches to 30-inches, the maximum center to center
Section 3 Wastewater Manholes
3-2
distance shall be 500 feet. Requirements of the Ten State Standards (TSS) shall apply for other sewer
sizes.
3.2 Manhole Type The following are the types of manholes installed in the City’s wastewater collection system.
3.2.1 Standard Manholes These manholes are placed at standard locations for manholes. Design all new manholes as pre-cast
manholes or cast-in-place manholes. Design all manholes with sufficient inside dimensions to perform
inspection and cleaning operations. During the preliminary design phase, the Design Engineer shall
determine the appropriate size and orientation of each manhole.
The minimum manhole diameter is 48-inches. Manholes greater than 72-inches in diameter shall be
considered special design, and approved by the City.
3.2.1.1 Pre-Cast Manholes
The Design Engineer shall review Standard Plan 2200-1 and Standard Specification Sections 209 and
2200 for requirements such as depth of pipe, type of pipe material, wall thickness and other design
factors. For any variation in design from these documents, it shall be necessary to show detail(s)
including the invert on the construction drawings and to provide structural calculations, as needed,
for approval by the City.
3.2.1.2 Cast-In-Pace Manholes
The Design Engineer shall review and use Standard Plan 2200-2 unless found unsuitable for the
project, in which case it shall be necessary to show the detail on the construction drawings and to
provide structural calculations, as needed, for approval by the City.
3.2.2 Drop Manholes These manholes are used where the incoming pipe or pipes are 2 feet or higher than the manhole
invert. Drop manholes should be constructed with an outside drop connection. Use Standard Plan
2200-7 for standard details acceptable to the City. Inside drop manholes are generally not preferred.
However, they may be considered on an as-needed basis. The Design Engineer shall submit written
justification for choosing an inside drop manhole for City’s review and approval. Minimum inside
diameter for inside drop manholes shall be 5 feet. The Design Engineer shall produce associated plans
and specifications when using inside drop manholes.
3.2.3 Vented Manholes These manholes are used in flood prone areas, and in 100 year flood plains. Manholes with external
vents shall have locked, and sealed manhole lid with the vent inlet located 2 feet above the base flood
elevation. Use Standard Plan 2200-5 for more details on vented manhole.
3.2.4 Discharge Manholes This type of manhole shall be used in situations where a force main terminates in a manhole. A flow
channel shall be provided at the base of the manhole to receive flow from force main. See Standard
Plan 2200-3 for a typical detail pertaining to discharge manholes.
Section 3 Wastewater Manholes
3-3
3.2.5 New Connections to Existing Manholes New gravity sewer connections to existing manholes shall be per the requirements stated in the City’s
Standard Specifications Sections 209 and 2200, and general engineering standards. However, direct
service line connections to existing manholes shall be limited to: one 4 inch service line per manhole.
Service line connections shall terminate at the manhole with a drop piping (see Section 3.2.2 of this
manual) to channel the flow, and the solids to the manhole invert.
3.3 Manhole Diameter Table 3-1 shows the diameter of manholes based on connecting sewer diameters:
Table 3-1 Diameter of Manholes
Diameter of Sewer, Inches Manhole Diameter, Feet1
≤15 4
>15 ≤ 27 5
>27 ≤ 36 6
>36 Special Design/As approved by City
1 – Inside diameter measured at the proposed flow line.
3.4 Manhole Flow Channel Manhole flow channels shall be made to conform as closely as possible in shape, and slope to that of
the connecting sewers. The channel walls shall be formed or shaped to the full height of the crown of
the outlet sewer in such a manner so as to not obstruct maintenance, inspection or flow in the sewers.
When curved manhole flow channels are specified including branch inlets, slopes shall be increased as
required to maintain acceptable velocities. A minimum drop of 0.1 foot shall be provided across new
manholes. In locations where pipes of differing sizes enter and exit manholes, the pipes shall be
installed such that their 0.8 pipe diameter points are at the same elevation. The channels shall be
constructed as illustrated in Standard Plans 2200-1 or 2200-2.
3.5 Manhole Castings Manhole frames and covers shall be non-rocking and shall conform to the City’s Standard Specification
Sections 209 and 2200 and the requirements of ASTM A48, Class 30. Unless otherwise indicated,
manhole frames shall be heavy-duty cast-iron type; 30-inches in diameter with a 24-inch opening.
Manhole cover inserts shall be 23 ¾-inch diameter consisting of the lettering "CITY OF SHREVEPORT"
and "SEWER". Locked and sealed manhole lids shall be used in flood hazard areas as defined by FEMA
or the City Engineer, and areas where water ponds or could pond, including traffic areas.
3.6 Manhole Access All sewer manholes outside the paved right-of-way shall have adequate vehicular access for sewer
maintenance vehicles. The manholes located within paved right-of-ways shall be located such that
adequate traffic control can be established so that maintenance functions can be performed without
incident. Design Engineer shall take into account the clearances required by the City’s maintenance
personnel, their equipment, and their vehicles.
Section 3 Wastewater Manholes
3-4
3.7 Manhole Coatings Manhole coatings shall conform to the City’s Standard Specification Sections 209. The manhole shall
be lined on the interior with a minimum 14 mils of coal tar epoxy coating. Vented manholes and
discharge manholes shall be lined on the inside with 100% solid flexibilized epoxy protective coating
with an 80-125 mil thickness. Special coatings and coatings for rehabilitated manholes shall be per the
City’s Standard Specification Section 2220.
3.8 Manhole Height Requirements under Various Conditions including Flood Plains 3.8.1 Height of Manhole Sidewall Manhole sidewall shall be of sufficient height such that a maximum of one adjustment ring will be
sufficient to bring the manhole frame and cover to the required elevation.
3.8.2 Traffic and Street Locations The manhole rim elevations shall be at grade level for all traffic and street locations.
3.8.3 Finished Landscape Locations The manhole rim elevations shall be located at the top of the mulch in finished landscape locations.
3.8.4 Non-Finished Landscape Locations The manhole rim elevations shall be located 3 inches above grade in non-finished landscaped areas.
3.8.5 Non-Traffic Areas In non-traffic areas, the manhole rim elevation shall be limited to 2 feet above the finished grade. As
manholes in non-traffic areas may not be readily visible due to overgrowth of vegetation, bollards
(painted yellow) shall be located around them to prevent damage from maintenance vehicles. Bollards
shall be located such that it doesn’t restrict access to the manhole for routine maintenance personnel
or equipment.
3.8.6 Flood Plains In flood plains, vented manholes with external vents shall have locked and sealed manhole lid with the
vent inlet located 2 feet above the base flood (100 year) elevation. Use Standard Plan 2200-5 for more
details on vented manholes.
4-1
Section 4
Wastewater Force Mains
4.1 Design Period The design period is the length of time the capacity of the Wastewater Force Mains are anticipated to
be adequate to service its tributary area. For the City of Shreveport, the design period for Force Mains
shall be 100 years.
4.2 Wastewater Design Flows The City may have access to wastewater model(s) which predicts wastewater flow from each sanitary
sewer area. In such cases, the City will provide the design flows for the force mains. When such
information is not available, design flow shall be estimated based on population estimates and type of
development. Such estimates shall be based on assumptions described in Section 2 of this manual.
4.3 Design Calculations 4.3.1 Wastewater Force Mains The Design Engineer shall select a suitable pipe material for the application based on past experience,
common engineering design practices, and the City’s Standard Specification Sections 209 and 2100. As
stated elsewhere in this manual, preference shall be given to PVC pipe. Pipe design calculations,
geotechnical information, material and dimension ratio/pressure class selection, pertinent written
justifications and relevant supporting documents shall be included in the Design Criteria report.
4.3.1.1 Hydraulic Design of Force Mains.
The Designer shall follow the guidelines listed below:
The design of a sewer force main must be coordinated with the design of the wastewater
pumping station. In the Design Criteria report provide the range of design flows for the
planning period, the proposed design of the pumping station, system curves, hydraulic
profile(s), surge analysis, proposed force main layout, restraint calculations and the force main
as a unified system.
Develop the proposed alignment in plan and depict the changes in force main elevations in
profile.
The number of air valve installations should be minimized. This can be achieved by reducing the
number of high points and slope breaks, and by using a profile that rises continuously from the
pumping station towards the destination/transition manhole.
Forcemains shall not be connected to other existing forcemains or sewer mains unless
approved in writing by the City.
Section 4 Wastewater Force
4-2
Using the system curves, develop the Hydraulic Grade Line (HGL) profiles.
The Hazen-Williams (HW) formula shall be used for hydraulic design and sizing of force mains:
Where,
Hf = Headloss (due to friction) in feet.
Q = Flow through pipe in gpm
C = pipe roughness coefficient
L = Pipe length in feet
d = pipe inside diameter in inches.
The roughness coefficient ‘C’ varies with velocity, pipe material, size, and age. As prescribed in the TSS,
the Design Engineer shall use a ‘C’ value of 100 for unlined Iron piping, and a maximum ‘C’ value of
120 for: Polyvinyl Chloride (PVC), Polyethylene (PE), and lined Ductile Iron (DI) piping. Exceptions to
these ‘C’ values shall be submitted to the City in writing for review and approval. Suitable value shall
be selected based on the abovementioned factors.
Minor losses from bends, valves, expansions, contractions, pipe entrance, pipe discharge, and other
fittings shall be accounted for as a function of velocity head. Minor losses can be determined by the
following formula:
Where:
hm = minor loss in feet
K = coefficient for minor loss item
V = velocity in ft./sec
g = gravity constant, 32 ft./sec2
K factors can be obtained from standard hydraulic reference manuals.
System curves shall be developed for the force main, which shows the total energy losses associated
with the following conditions:
1. Maximum static head and low C factor
2. Maximum static head and high C factor
3. Minimum static head and high C factor
4. Minimum Static head and low C factor
Section 4 Wastewater Force
4-3
Develop HGL profiles for the range of pumping rates (minimum, average and maximum rates) planned
for the pumping station.
For calculating friction losses in an existing force main, existing flow and pressure data, if available for
the force main and pump station can be used to determine the HW friction factor. The Design Engineer
shall also consider the future operating conditions of such existing pumping and piping systems
during design, to check that the design serves the future requirements as well.
Base the static head on the difference in vertical elevations between the wet well low operating level
and the point of force main discharge or the highest point on the force main, when this point is the
highest point in the entire pumping system.
In general, a minimum velocity of two (2) feet per second (fps) is required to maintain solids in
suspension. Velocities ranging from three (3) to three and one half (3.5) fps would be required
to re-suspend solids that have settled in the force main. Since most of the City’s pump stations
will operate intermittently or on reduced speeds, design force mains to maintain a 3 fps
velocity.
The maximum velocity in a force main shall be limited to six (6) fps. High velocities generate
high head losses, and increase the potential for severe water hammer pressures. Flow velocity
can vary in a force main, depending on the number of pumps operating in a pumping station.
Base the maximum force main velocity on the peak pumping rate anticipated during the peak
wastewater influent condition.
Where Variable Frequency Drives are used, the Design Engineer shall select a pipe size that
accommodates a range of velocities.
The Design Engineer shall submit written justification for City’s review and approval, if they
choose to use minimum and maximum velocities outside of the prescribed ranges.
The minimum size for a force main is 4-inches (diameter).
Where feasible, it may be desirable to minimize the length of the force main so as to minimize
the cost of construction and operation. Proper consideration shall be given to situations such as
utility crossings/stream crossings to avoid, and environmental impacts among others.
Limit joint deflections to 50% of the manufacturer’s recommendations.
Vertical alignment
- Uphill pumping is preferred in a force main, where the force main discharge point is at a
higher elevation than the rest of the system, so as to keep the force main under pressure.
- If an intermediate high point in the force main lies above the downstream point of the
discharge, a partial vacuum condition can be created at the high point when the force main
drains after pumps shut off, and when the HGL profile drops below the high point. When
possible, high points in the piping system shall be avoided. Where high points are
unavoidable, air release and air/vacuum valves shall be installed.
- Downhill pumping, vertical profiles which are conducive to siphoning at high points and
gravity drain/air locking in downhill pumping conditions will require special analysis to
Section 4 Wastewater Force
4-4
verify proper hydraulic performance. These types of force main profiles are also conducive
to severe water hammer pressures caused by rapid velocity change in the force main
resulting from pump start up or shut down. It is therefore recommended that force main
profiles which can generate downhill flow be avoided. If downward pumping condition
cannot be avoided, then proper hydraulic performance of the force main should be verified
based on sound engineering and design principles. Consider the following, when downhill
pumping is required.
o A downward sloping force main section following a high point may not flow full
during initial line start up because the flow carrying capacity would exceed the line
filling rate. The elevation of the high point, in this case, will give the highest static head
that the pump must overcome during initial start-up.
o A downward sloping force main section may not flow under pressure at some
pumping rates during normal operation of the pumping station and when pumps shut
down. Consider if (and how) pressurized pipe flow should be achieved and
maintained.
o The extent and effects of partial vacuum condition/siphon action on force main’s
hydraulic performance.
o Trapping of air/sewer gases at the high point and the downward sloping section, and
the effects on pumping head and removal of the air/gas from the force main.
o Potential water hammer pressure due to pump shutdown or power failure.
o Evaluate the severity of water hammer pressures in the force main under the worst
case scenario, assuming power failure at the pumping station coincides with firm
pumping capacity. Upon power failure at the pumping station, severe down surge (low
pressure) can propagate throughout the entire force main, followed by upsurge (high
pressure). Examine the potential for water column separation in the force main.
Methods of water hammer pressure control and relief should be incorporated, if
necessary.
Consider the operating pressure and the surge pressure in designing restraints for the force
main.
Submit drawings, details and final hydraulic calculations to support the force main design.
4.3.1.2 Hydraulic Transients
Hydraulic transients are the time-varying phenomena that follow when the equilibrium of steady flow
in a system is disturbed by a change of flow that occurs over a relatively short time period.
Surge Control for Raw Sewage Force main: The strategies for controlling surge in raw sewage
force main/ sewage pumping stations are limited as compared to the pumping of clean water,
because some of the valves (globe and butterfly, for example are unsuitable), the reliability of
other valves (such as vacuum and air release) depends on frequent and vigilant maintenance,
and air chambers are far more maintenance-dependent for sewage than for water. However,
adequate control strategies remain and any proposed solution should be checked thoroughly.
Section 4 Wastewater Force
4-5
Transients are important in hydraulic systems because they can cause rupture of pipe and
pump casings, pipe collapse, vibration, excessive pipe displacements, pipe fitting and support
deformation /failure, vapor cavity formation, cavitation and column separation. Computer
modeling is effective, but it could be expensive and time consuming. The Design Engineer shall
submit to the City, for review, all calculations pertaining to transient analysis. The following
guidelines can be used to decide if a complete transient analysis is required:
- Do Not Analyze
o Pumping station with flow rate less than 100 gal/min. Discharge velocities for such
systems is usually low and therefore transient pressures are also low.
o Pipelines with velocity less than 3ft/sec.
o Distribution networks or piping networks, as pressure in these systems are usually
dissipated at the junctions.
o Pumping systems with a static differential pressure between suction and discharge of
less than 30 ft. However, it is possible that a very low static head coupled with a
relatively high dynamic head could result in a column separation problem
- Do Analyze
o Pumping systems with a total dynamic head above 50ft if the flow rate exceeds 500
gal/min.
o For pipe diameters above 8 inches, when piping length is in excess of 1000 feet.
o Pumping systems designed for high lift that include a check valve. Flow reversal in
such systems could result in the check valve shutting (slamming) instantaneously,
resulting in high surge pressures.
o Valves on the system that are not equipped with limit switches, and are capable of
being opened or closed instantaneously.
o A system in which column separation can occur include:
Systems with high points.
A force main with air-vacuum valves.
A pipeline with a long (over 300ft.), and steep gradient followed by a long,
relatively flat gradient.
The Design Engineer is hereby recommended to consult the ‘Checklist’ as stated in
‘Fundamentals of Hydraulic Transients’ chapter of the latest edition of ‘Pumping Station Design’
by Robert L. Sanks.
Surge may occur when there is a slowdown, followed by a reversal of flow in less than Critical
Period (tc). The critical period (tc) is the roundtrip time of travel of the pressure wave from and
back to the point of flow change, and is given by the following equation:
Section 4 Wastewater Force
4-6
tc = 2L/a,
Where:
L = length of force main between point of flow change and point of reflection, (ft.)
a = velocity of pressure wave, (ft./sec).
The velocity of a water hammer pressure wave depends primarily on the physical properties
of the fluid and the force main pipe material. It can be calculated using the following equation:
√
( ) (
)
Where:
K = Bulk modulus of elasticity of the liquid in psi (300,000 psi for water)
ρ = Density of the liquid in lbs./cu.ft.
E= Modulus of elasticity of the pipe in psi
D = Internal pipe diameter in inches
t= pipe wall thickness in inches
c= (1.25 - µ) for piping free to move longitudinally
c = (1-µ2) for restrained piping
c = 1 for piping with expansion joints
Where, µ = Poisson’s ratio
4.3.1.3 Required Analysis for Hydrogen Sulfide (H2S) Generation and Release
Perform a hydrogen sulfide analysis for the proposed design to determine the potential for
hydrogen sulfide gas generation. EPA’s design manual ‘Odor and Corrosion Control in Sanitary
Sewerage Systems and Treatment Plans’ is recommended for use as a reference.
Design the system piping layout to minimize the total piping lengths and pipe sizes within the
constraints of the hydraulic design criteria, so as to minimize sewage detention time in the
system. Downhill pumping conditions with a high point above the transition manholes will
potentially cause the release and accumulation of hydrogen sulfide gas at the high points. Avoid
high points in the design, if possible.
The discharge of sewage from a force main into a gravity sewer can potentially generate odor and the
release of hydrogen sulfide at the transition manhole and in the downstream gravity sewer.
Turbulence in the transition manhole should be minimized. When selecting/designing gravity sewer
pipe material downstream of transition manholes, consider the corrosive effects of hydrogen sulfide.
Section 4 Wastewater Force
4-7
4.4 Location Force mains shall be located a minimum of 36 inches below grade. When traversing servitudes owned
by other agencies, the Design Engineer shall meet the minimum cover requirements set forth by such
agencies. Backlot or sidelot servitudes will not be allowed.
Wastewater Force Mains shall be located in the following locations:
Public right-of-way
Permanent access servitude with overlapping public utility servitudes
Dedicated servitude adjacent to and contiguous with the right-of-way (upon City approval)
Separate dedicated servitudes (upon City approval)
Replacement mains should be located three feet parallel to the existing mains.
4.5 Thrust Restraint Systems Force mains are subject to hydraulic thrust forces at locations where there are changes in direction or
diameter, tees, or termination at a plug or a valve. Thrust is generated by internal hydrostatic pressure
and dynamic forces. Dynamic forces are usually not significant in pipelines unless velocity head is
large in comparison with hydrostatic pressure. In high velocity pipelines, however, dynamic thrust
may be sizeable.
Forcemain joints and its fittings shall be restrained using restrained joints. Restrained joint design is
specific to the pipe material and manufacturer. The design method should consider safe bearing load
of undisturbed soil, soil cohesion, angle of internal friction, and soil unit weight. Restrained lengths
requirements for all fittings used shall be tabulated in the plans. Valves shall be considered dead ends
and restrained accordingly. A safety factor of 1.5 shall be used when calculating the restraining length.
The following technical references shall be used for calculating thrust restraint system as required:
Thrust Restraint Design for Ductile Iron Pipe, Latest Edition
AWWA M23: PVC Pipe Design and Installation, Latest Edition
Design Engineer shall submit pertinent calculations and justification (including cost savings, if any) for
an alternate thrust balancing method chosen (ex: thrust blocks), for the City’s review and approval.
4.6 Force Main Servitudes Both Construction and Maintenance Force Main servitudes will observe the same requirements for Gravity sewer. The Design Engineer
shall refer to Section 2.10 of this manual for additional information for servitudes.
Section 4 Wastewater Force
4-8
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5-1
Section 5
Trenchless Technologies
5.1 General Owing to the age, and condition of the existing pipeline infrastructure, and to meet future demands,
there will be a need to replace and rehabilitate the City’s sewers. Many of these sewers are located
in/near streets and public roadways or under streams. The method currently used most often for
pipe laying is the open-trench method. Open trench construction methods have several shortcomings
such as:
Health and safety concerns of workers.
Surface disturbance.
Disruption to vehicular/pedestrian traffic.
Reduction in paving life.
Potential damage to structures due to deep excavations.
Exposure of potentially contaminated soils.
Dewatering to provide stable excavation and bedding.
The use of trenchless technologies eliminates many of these potential problems. The need to replace
deteriorating underground utility infrastructure, and to expand utility services increases the need for
utility conduits to intersect roadways or cross streams. Trenchless technologies are cost-effective
alternates that provide for the installation of conduits beneath roadways or under streams with
minimal trenching (excavation). These technologies also have the potential of reducing environmental
impacts, and have the added benefit of minimizing the handling, treatment and/or disposal of
contaminated soil.
Trenchless techniques can be divided into two categories based on the project: techniques available
for pipelines renewal, and techniques for new pipelines construction. The technique most suited for
pipelines renewal projects is Cured in Place Pipe (CIPP). Techniques most suited for new pipeline
construction are: pipe boring and jacking, horizontal directional drilling and pipe bursting, among
others.
The Design Engineer shall select a trenchless option best suited for the application, by taking into
account soil conditions, costs, tolerance, land requirement (overall footprint for the operation)
amongst other factors. Certain trenchless techniques are discussed in detail in the following sections.
5.2 Boring and Jacking 5.2.1 Boring Boring is a trenchless technology typically used for installing pipes across railways, and roads. It is
widely used where rail road/paving damage, and or traffic disruption need to be avoided. Casing pipe
Section 5 Trenchless Technologies
5-2
that can be installed by boring ranges from 4 inches to 72 inches in diameter. In this method a drill
with a cutting head is used to bore holes. Typically, the cutting head is attached to an auger located
inside a casing. The boring machine generates torque, which is transmitted to the cutting head
through a flighted auger.
The boring operation requires a driving pit and a receiving pit. Typical pit sizes are 38 feet in length,
10 to 12 feet in width, with the bottom of the pit located 2 feet 8 inches below the center line of the
bore. The boring equipment including auger boring machine, augers, and cutting head is located in the
driving pit. Spoils are removed from the bore hole, at the backside of the casing in the driving pit, by
the movement of helical wound auger flights. The vertical alignment of the auger boring operation can
be monitored using a water level. Upon completion of the bore, the carrier pipe is installed within the
casing. Table 5-1 shows the Design Engineer the minimum casing sizes based on the carrier pipe size.
Table 5-1 Casing Sizes
Carrier Pipe
Diameter, inches
Minimum Casing
Diameter, inches
Casing nominal
Thickness, inches
6 12 0.344
8 16 0.375
10 20 0.406
12 24 0.469
14 30 0.500
16 30 0.500
18 30 0.500
20 36 0.562
24 36 0.562
30 42 0.625
36 48 0.688
42 60 0.875
5.2.2 Pipe Jacking Pipe jacking is a trenchless method for installing a prefabricated pipe through the ground from a drive
pit to a reception pit. Pipe jacking involves, advancing the pipe using jacks located in the drive pit.
The jacking force is transmitted through the pipe to the face of the excavation. Once the excavation is
accomplished, the spoils are transported out of the jacking pipe and shaft either manually or
mechanically.
Pipe jacking is well suited to situations where a pipeline has to conform to rigid line and level criteria.
The most common application of this technique is for installing gravity sewers, especially where the
depths are cost prohibitive when installed by open cut methods.
In order to install a pipeline using this technique, thrust (driving) and reception pits are constructed,
usually at manhole positions. The dimension and construction of a thrust pit may vary according to
the specific requirements of the drive, with economics being a key factor. Mechanized excavation may
require larger pits than hand excavated drives, although pipe jacking can be carried out from small
shafts to meet special site circumstances. A thrust wall is usually constructed to provide a reaction
against which to jack. In poor ground, piling or other special arrangements may have to be employed
to increase the reaction capability of the thrust wall. Where there is insufficient depth to construct a
Section 5 Trenchless Technologies
5-3
normal thrust wall, for example through embankments, the jacking reaction has to be resisted by
means of a structural framework constructed above ground level having adequate restraint provided
by means of piles, ground anchors or other such methods for transferring horizontal loads. The
number of jacks used may vary because of the pipe size, the strength of the jacking pipes, the length to
be installed and the anticipated frictional resistance. A reception pit of sufficient size for removal of
the jacking shield is normally required at the completed end of each drive. The initial alignment of the
pipe jack is obtained by accurately positioning guide rails within the thrust pit on which the pipes and
jacks are laid. To maintain accuracy of alignment during pipe jacking, it is necessary to use a steerable
shield. This shield must be frequently checked for line, and level from a fixed reference. For short or
simple pipe jacks, these checks can be carried out using traditional surveying equipment. Rapid
excavation and remote control techniques require sophisticated electronic guidance systems using a
combination of lasers and screen based computer techniques.
5.3 Horizontal Directional Drilling Horizontal Directional Drilling (HDD) utilizes steerable soil drilling systems to install trenchless
pipelines from 2 inches to 36 inches in diameter. Typically, the new pipeline is constructed of HDPE
or fusible PVC, but other materials have also been utilized. In most cases, HDD is a two-stage process.
In the first stage, a pilot hole of 1 to 5 inches in diameter is drilled along the proposed pipe centerline.
This pilot hole sets the path for the following operations. In the next stage (called back reaming), a
reamer is pulled through the path set by the pilot hole (in the opposite direction) to sufficiently
enlarge the bore. The back reaming stage may require multiple passes with sequentially larger
reamers to achieve a borehole (typically no more than 150% of the final pipe OD) Once the borehole is
established, the pipeline is pulled back through the borehole using the steel drill string from the exit
side towards the drill rig. This requires that the entire length of pipe for the crossing is fused or
jointed so that the pullback is accomplished without stopping. Where space is limited, the number of
stops for intermediate fusing needs to be limited to one or two times to reduce the possibility of the
pipe “freezing” in the borehole.
The pilot hole is drilled with a surface-launched rig with an inclined carriage. An entry angle of 8 to 18
degrees with the ground is typically required in order to develop the depth needed to avoid an
obstacle (such as another utility) or to provide the minimum cover under the roadway or water body
being crossed. An exit angle of 8 to 12 degrees is preferred to reduce the bending forces and supports
needed to protect the pipe during pullback. The preferred minimum radius in feet for steel pipe,
including the drill string, is 100 feet per inch diameter of the pipe. For plastic pipe, the minimum
radius is 25-40 feet per inch diameter of the pipe. For smaller diameter pipelines, the steel drill string
size will control the minimum radius. The size of the drill rig and the drill string will increase with the
length and size of the crossing and the drilling torque and pullback tensile forces that will be required.
5.3.1 HDD for Gravity Sewers The Design Engineer should consider HDD for gravity sewers only when the pipe slope is greater than
one percent, and there is a drop of greater than 1 foot at the downstream manhole. Pipe for directional
drilling shall be HDPE (AWWA C906) with heat fusion welded joints meeting the City’s Standard
Specification’s (Section 209) requirements or fusible PVC with a minimum DR 18 (AWWA C900) or a
minimum DR25 (AWWA C905).
Section 5 Trenchless Technologies
5-4
5.3.2 HDD for Force mains The Design Engineer shall follow the HDD requirements contained in ASTM standards, AWWA
Standards, and the manufacturer’s recommendations.
Fusible PVC will be allowed for HDD installations in nominal diameters up to 24 inches. Maximum
lengths should not exceed manufacturer’s recommendation. HDD Installations in diameters larger
than 24 inches must use HDPE as the pipe material. HDD Installations will be limited to a maximum
length that does not exceed the manufacturer’s recommendations.
Pipe used in HDD shall be capable of withstanding:
The maximum internal pressure.
The maximum external loading configuration acting independently.
The maximum pulling forces during HDD installation.
The Design Engineer shall consider dead loads, concentrated live loads, construction loads (including
tensile stress and capstan forces during pullback), and distributed loads acting on the pipe. The
minimum required safety factor is 2.0. Safety factors between 1.5 and 2.0 may be considered on a
case-by-case basis and requires approval by the City.
The Design Engineer is to consult with both an experienced HDD contractor and an engineer
experienced in HDD. The Design Engineer shall adhere to the following requirements:
Select the crossing route to keep it to the shortest reasonable distance.
Find routes and sites where the pipe can be laid out, fused and pulled in in one continuous
length.
Avoid compound curves.
Maintain a minimum cover of 15 feet over the installed pipeline at canals, bayous, creeks, and so
forth to minimize the potential for lost drilling fluids.
Avoid entry and exit pit elevation differences in excess of 25 feet.
Locate all buried structures and utilities within 25 feet area of the drill path.
Avoid design where the drill rig is directly below aboveground structures such as power lines.
Identify and layout site space to accommodate the required drill equipment, including the
drilling mud plant, and pipe size and length. (Site space varies depending on the crossing
distance, pipe diameter and soil type.)
5.3.3 Engineering Calculations The Design Engineer is referred to ASTM Standard F1962 ‘Standard Guide for the Use of Maxi-
Horizontal Directional Drilling for Placement of Polyethylene Pipe or Conduit Under Obstacles,
Including River Crossings’ for the production of the required calculations. Calculations shall be
provided to the City for review.
Section 5 Trenchless Technologies
5-5
5.3.3.1 Pullback Calculations
The Design Engineer shall perform pullback calculations for the selected pipe material. The
calculations shall include:
Average radius of curvature for both the pipe entry and exit points.
Horizontal distance required to achieve depth or rise to the surface at the pipe entry and exit
points.
Axial bending stress.
Bending stress.
Weight of empty pipe.
Net upward buoyant force on empty pipe surrounded by mud slurry.
Pullback force acting on pipe at Points 1, 2, 3, and 4 (see Figure 5-1).
Compare axial tensile stress with allowable tensile stress during forcemain pullback at Points 1,
2, 3, and 4 (see Figure 5-1)
External static head pressure.
Combine static head pressure with hydrokinetic pressure.
Determine the reduction factor.
Calculate the critical buckling pressure due to head of drilling fluid water.
Determine the safety factor against ring collapse during pullback.
Refer to Figure 5-1 and the following assumptions when performing the pullback calculations:
- Minimum depth (H) = 15 feet
- Pipe drag on surface (this value starts at total length of pull, then decreases with time)
assume L1 = 100 feet remaining at end of pull
- Minimum distance for L3 shall be no less than 100 feet.
- Entry and exit pit shall be between 1:3 to 1:4 (rise/run)
- Assume pipe is empty during pull back.
- Hydrokinetic pressure = 10 psi
- Ovality compensation factor (for 3 percent ovality) = 0.76
Section 5 Trenchless Technologies
5-6
Figure 5-1 Horizontal Directional Drilling Pullback
5.3.3.2 Long Term Operation Calculations
The following calculations shall be performed at a minimum for the long term operation of the pipe:
Approximate arching factor.
Approximate external earth pressure. A geotechnical engineer shall determine the earth
pressure value based on the properties of soil formation. This is an estimated value for a typical
case (or preliminary calculations) and shall not apply to the actual application.
Ring deflection.
Determine long term total external hydrostatic and buoyant soil load on pipe.
Critical unconstrained buckling pressure.
Long term operational safety factor against buckling for pipe in service.
The following initial assumptions can be made in the long term operational calculations.
However, these are only to be used for preliminary calculations and shall be replaced with
actual data collected during the geotechnical evaluation:
- Unit weight of soil = 120 pcf
- Groundwater elevation = H depth, as shown on Figure 5-1
- Unit weight of water = 62.4 pcf
- Internal angle of friction = 30 degrees
- Angle of wall friction = internal angle of friction divided by 2
- Earth pressure coefficient = 0.5
Section 5 Trenchless Technologies
5-7
5.3.3.3 Geotechnical
The Engineer shall conduct a comprehensive geotechnical investigation to identify the following:
Type of soil.
Where rocks exist, if any.
Existence of gravely soils, loose deposits, discontinuities, and hardpan.
Soil strength, and stability characteristics.
Existence of ground water.
For crossings greater than 1,000 feet in length, borings shall be taken at 500-foot maximum
intervals. For short crossings(1,000 feet and less), three borings shall be performed, specifically
one boring near the entry pit, one boring near the exit pit, and one in the approximate middle of
the HDD path. Borings shall be made at a minimum distance of 20 feet, and a maximum of 50
feet horizontally from the bore path and shall be taken to at least 20 feet below the design depth
(H).
5.3.3.4 Land Requirements
The Design Engineer shall estimate the rig side land requirements to conduct the HDD, assuming that
the contractor will use the following equipment at a minimum: rig unit, control cab power unit, drill
pipe, water pump, slurry mixing tank, cuttings separation equipment, slurry pump, bentonite storage,
power generators, spares storage, site office (if needed), entry point slurry containment, and a
cuttings settlement pit.
The Design Engineer shall estimate the pipe side land requirements to conduct the HDD, assuming
that the contractor will use the following equipment at a minimum: cuttings settlement pit, exit point
slurry containment pit, pipe rollers, pipe product (with enough room to fuse the pipe together and
leave it on the rollers), drill pipe, and spares storage.
5.4 Pipe Bursting 5.4.1 General Pipe bursting is a technique for breaking an existing pipe with a bursting head and simultaneously
pulling a new pre-manufactured flexible pipe into the host pipe. The remains of the existing host pipe
are broken into pieces, and forced into the surrounding ground. The rear of a proper sized bursting
head is attached to the new pipe, and the front end is attached to a winch cable or a pulling rod which
is then hooked to a tool that will help keep it in-line as it progresses through the existing line. As the
bursting head assembly moves forward it is simultaneously winched or pulled forward. This action
bursts the existing pipe, and pushes the pieces of old pipe into the surrounding soil no further than the
outside edge of the bursting head as the new pipe is pulled into place. When the bursting head has
reached its destination, the stake down unit and winch cable are removed and the tool is placed into
reverse. The reverse action of the tool helps to back it out of the new line all the way to the launch pit.
The bursting head is then cut off, and removed to complete the installation of the new pipe.
Section 5 Trenchless Technologies
5-8
5.4.2 Pipe Bursting Design The Design Engineer should adhere to the maximum depths and lengths as shown in Table 5-2 for
pipe bursting.
Table 5-2 Pipe Bursting Design
Pipe Busting Maximum Depth and Length
Pipe Diameter, inches Maximum Depth,
Feet
Maximum Length,
Feet
Maximum Upsize
Pipe Diameter
≤ 12 12 350* 18
>12 ≤ 18 18 450* 24
* For gravity sewer lines, the maximum length shall be the length between two consecutive manholes. Design Engineer shall verify feasibility of pipe
bursting.
Pipe bursting is generally not allowed in the following cases:
Sewers deeper than 18 feet.
Pipes larger than 24 inches.
Upsizing more than two pipe diameters or 1.5 times the diameter of the host pipe.
Lengths greater than 450 feet.
When pipe sags more than 20 %.
When pipe sags extend more than 8 feet.
When pipe is located under railroads, buildings, or structures.
When pipe is located in a rock trench.
Pipes encased in concrete.
Piping with significant number of valves.
Piping that include steel joint bands.
The Design Engineer shall perform soil investigation activities such as soil borings, standard
penetration tests, unconfined compression tests, moisture content tests, and groundwater readings to
determine the feasibility of pipe bursting. Compressible clay soil is ideal for pipe bursting. Special
attention shall be paid to pipe diameter when the replacement pipe is HDPE.
Most brittle pipe materials such as clay, non-reinforced concrete, PVC, cast iron, and asbestos-cement
pipe make good candidates for pipe bursting. Steel, and ductile iron pipes are not good candidates for
pipe bursting due to their strength and ductility. Inter- seam process shall not be allowed.
Owing to their continuity, flexibility and versatility, HDPE is preferred for pipe bursting and it is
preferred over other pipe materials. Pipe joints are to be fused and cooled prior to bursting. Other
piping material can also be used for pipe bursting when space is limited.
Section 5 Trenchless Technologies
5-9
Minimum cover of the new pipe shall be:
10 times the burst displacement.
3 times the new pipe diameter.
4 feet below the ground surface.
3 feet clear from the nearest utility.
The Design Engineer shall consider the surrounding utilities that can affect the location, and size of the
pit(s) for pipe bursting. Any utilities that may interfere or may be damaged by the burst shall be
located, and exposed prior to the burst. Pipe bursting lubricants shall always be used to reduce
friction and relaxation shortening. The minimum relaxation period shall be 24 hours. As sewer depth,
pipe size, degree of pipe up-sizing and burst lengths increase, the relaxation period shall increase.
Open cut replacement shall be considered when a line to be pipe bursted has 4 laterals every 200 feet.
5.4.3 Crushed Liner Process A variation on the pipe bursting process is the crushed liner process. In this method, the pipe bursting
head has a cutting head integrated with a pneumatic hammer which supports the destruction and
crushing of the old pipe. The exhaust air of the hammer is use to convey the crushed pipe pieces from
the region of the cutting head into the conveying screws. This material is then moved through the
pipe into the launch pit for disposal.
5.5 Cured in Place Pipe 5.5.1 General The cured-in-place pipe (CIPP) lining process is used for rehabilitating existing sewer pipes without
having to replace the pipes.
CIPP uses a felt liner that is impregnated (typically under a vacuum) with thermoset resin which is
expanded with air or water under pressure to form tightly against an existing pipeline. The liner can
be cured with hot water, steam/hot air, ultraviolet lights (UV) or ambient conditions (time). CIPP has
the inherent advantage of conforming to almost any shape of pipe, making them suitable for relining
non-circular cross-sections, and resolving pipe defects.
CIPP creates a close-fit “pipe-within-a-pipe” which has quantifiable structural strength, and can be
designed to suit various loading conditions. The ring-stiffness of the liner is enhanced by the restraint
provided by the host pipe and the surrounding ground. ASTM F1216 can be used as a guideline for
design of the wall thickness of gravity flow, circular CIPP installations. Other more recent publications
can also be utilized for proper design of the liner. Other design methods including WRC manuals of
practice can be used for non-circular designs and pressure pipe applications. The assumptions
selected for the design should only be chosen by an engineer experienced in the proper design of CIPP.
Liner’s structural design should enable it to withstand all of the live and dead loads. Professional
judgement is also recommended to avoid an over-designed system which can result in waste of money
or cause installation problems. Table 5-3 lists the size and length limitations for both methods.
Section 5 Trenchless Technologies
5-10
Table 5-3 CIPP Method Limitations
Item Acceptable Parameter
Typical Application Wastewater Main, Gravity or Force main
Host Material PVC, Clay, DI
Liner Pipe Size – Inverted 8 inches to 108 inches
Liner Pipe Size – Winched 8 inches to 100 inches
Liner Material ASTM D5813, Specify Class I,II or III Thermoset Resin/ Fiber
Composite
Max Installation Inverted 3000 feet
Max Installation Winched 1500 feet
5.5.2 CIPP Guidelines CIPP should be considered when:
There is only moderate or less active infiltration into the pipe.
Where pipe joint offsets are 1 inch or less for small diameter pipes.
Where there is minimal structural deformation from longitudinal and circumferential cracking.
Where root intrusion can be removed through interior cutting.
Where sags in pipelines are less than 25 percent of pipe diameter. Sags should be repaired if
they have significant impact on the flow, sewer capacity or debris is getting trapped frequently
in the sag.
Where all protruding service laterals have been properly repaired.
Where point repairs exhibit minimum settlement, flow restriction, offset or structural
deformations.
Where there is severely exposed surface aggregate.
CIPP should not be considered when:
If major infiltration/inflow is observed in the pipe that can’t be sealed with a chemical grout or
other means.
When pipes have holes with visible voids in the soil surrounding the pipe.
When structural damage has occurred such that a camera cannot pass through the defective
pipe section.
Where excessive cleaning is needed which may result in collapse of the pipe.
Multiple point repairs are required before installation, and 25% or more of the existing pipeline
must be replaced.
Section 5 Trenchless Technologies
5-11
5.5.2.1 Lateral Repairs
Additional considerations are required for the existing service connections or laterals to meet the
goals of each project with regards to infiltration reduction, lateral blockages, intruding taps, defective
taps, root intrusion and other similar issues. The laterals may need to be replaced or relined with
CIPP to meet the goals of the project and customer needs.
Section 5 Trenchless Technologies
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6-1
Section 6
Wastewater Lift Station Design
The primary objective of this section is to provide dependable wastewater pumping facilities, and to
provide reliability in conformance with EPA Class I reliability standards for mechanical and electrical
components and alarms.
6.1 Wastewater Design Flows Projected wastewater inflow to a lift station shall be calculated using the procedure outlined in
Chapter 2 of this manual and the City of Shreveport’s Master Planning Document. As stated in Section
2.1, it shall be the Design Engineer’s responsibility to verify any data provided by the City based on
detailed survey information and field review of the project collection system, note any potential
inconsistencies in the provided flow data and present them to the City. In instances where
hydraulic/hydrology models are not available to the City, the design engineer shall provide the
following information:
Total acreage in the lift station watershed.
Total population and acreage of existing developments to be served by the lift station.
Total population and acreage of proposed developments to be served by the lift station.
Average day and peak hourly inflow to the lift station.
Minimum force main size shall be 4 inches in diameter. Lift stations are permitted only for areas or
basins with 200 households or more. Gravity sewers shall be used for areas not meeting the
aforementioned criteria.
6.2 Number of Lift Station Pumps A minimum of two pumps shall be installed in each lift station, with one pump serving as a standby
unit. For duplex pump stations, each pump shall be capable of pumping the peak hourly flows with
one pump out of service. For larger pump stations, the ability to pump the peak hourly flow rate shall
be provided with the largest pump out of service.
6.3 Wetwell Design The wetwell design, including wetwell geometry, shall adhere to the latest version of the Hydraulic
Institutes Standards, and Ten State Standards. The sizing of the wetwell is dependent on whether the
pump drives are variable speed or constant speed.
6.3.1 Wetwell Volume for Variable Speed Pumping Where variable speed pumps are used, the pump station firm pump capacity is used for wetwell
design. The maximum pumping capacity with one out of service is the pump station’s firm capacity.
The Design Engineer shall take into account the minimum submergence recommended by the
Section 6 Wastewater Lift Station Design
6-2
manufacturer in selecting the ALL PUMPS OFF elevation. The Design Engineer shall also consult the
City’s Water and Sewerage personnel during design to establish wetwell operation set points.
6.3.2 Wetwell Volume for Constant Speed Pumping For constant speed pumps, the PUMP OFF elevation shall be determined using the following equation:
Pump Off Elev = Ve/Aw
Where Ve is the effective pumping volume in cubic feet, and Aw is the wet well cross sectional area in
square feet. The effective pumping volume may be estimated as follows:
Ve = Q*tmin/7.481*4
Where Q is the design wet weather flow rate in gallons per minute, Ve is the effective pumping volume
in cubic feet, and tmin is the minimum time interval in minutes allowed in one pumping cycle.
Minimum cycle time (tmin) is calculated as follows:
tmin = 60min/No of cycles per hr
The time within one pumping cycle shall be limited in order to prevent motor insulation failure due to
overheating. When a motor starts, the inrush current may be significantly higher than normal
operating current, resulting in significant heat generation. Hence frequent motor starts do not give the
motor adequate time to “cool down” between starts. The Design Engineer shall also refer to NEMA
standards.
Pump cycle times shall generally be in accordance with the manufacturer’s recommendation, or
limited to a minimum cycle time of 15 minutes (at design flow), or pursuant to the Ten State
Standards, in the absence of a manufacturer’s recommendation. For cycle times less than 15 minutes
at design flow, the Design Engineer shall obtain written verification from the pump and motor
manufacturer that cycle time is acceptable. Pump cycle times shall not exceed manufacturer
recommendations and NEMA standards.
Wetwell storage volume shall be such that detention time is less than 30 minutes at dry weather flow,
per the Ten State Standards, to minimize septic conditions and odor generation. For low flow
conditions, controls shall cycle the pumps at a minimum of once every 30 minutes.
6.3.3 Wet Well Appurtenances The Design Engineer shall determine if bar screens and basket screens are required for the pump
station. Mechanical bar screens shall not be used. Screens shall be in accordance with Chapters 40 and
60 of the TSS.
6.4 Lift Station Design Calculations and Procedures Lift station design calculations shall commence by establishing inflow to the lift station as outlined in
Section 6.1 of this Chapter, followed by hydraulic analysis of the pumping system. A suitable pump
shall be selected based on the application, and it shall be verified against the forcemain sizing, fittings
used, solids content of the fluid, and head requirements.
Section 6 Wastewater Lift Station Design
6-3
6.4.1 Pumps Selection Pumping selection includes choosing the type of pump for the application (for example, non-clog
pumps for raw sewage, recessed impeller pumps for gritty flows etc.), sizing the pump based on
calculated flowrates and head losses, developing a range of system curves, followed by verifying the
pump curve against the system curves. Where practical or required, pump selection shall include non-
overloading motors. For pumps operated on variable frequency drives, the reduced speed curves shall
also be verified against the system curve. Special attention should be given to the pump selection
when the pump station is discharging into a force main which serves other pump stations.
6.4.1.1 Pumps
The most efficient pump for the anticipated flows, during all phases of expansion shall be selected.
The pump configuration shall be parallel unless otherwise approved by the City. Pump stations shall
include a minimum of two pumps, each capable of handling the peak wet weather flow. For
installations with more than two pumps, the pump station must be capable of handling the peak wet
weather flows with the largest pump (based on capacity) out of service.
As pump station flows vary over time, the design engineer shall design the pump station to handle
such flows from initial startup to ultimate build-out. The pumps shall be designed to operate
efficiently at average flows while providing enough capacity to handle anticipated wet weather peak
flows.
6.4.1.2 System Head Curve
The Design Engineer shall prepare a set of pump curves to simultaneously represent the System Head
operation under a wide range of situations using the Hazen Williams formula.
Where,
Hf = Headloss (due to friction) in feet.
Q = Flow through pipe in gpm.
C = pipe roughness coefficient.
L = Pipe length in feet.
d = pipe inside diameter in inches.
The Design Engineer shall analyze pump performance at the following conditions:
Hazen William’s ‘C’ value selection shall be in accordance with Section 4.3.1.1 of this manual. Owing to
varying static head conditions and forcemain losses, the Design Engineer shall generate four system
curves to address the following conditions:
1. Low Static Head, Low ‘C’ value. 2. Low Static Head, High ‘C’ Value 3. High Static Head, Low ‘C’ Value 4. High Static Head, High ‘C’ Value
Section 6 Wastewater Lift Station Design
6-4
System curves at these conditions, in conjunction with the pump curve(s) will define the operating
range for the pump(s). In addition, the Design Engineer shall also develop the Net Positive Suction
Head Available (NPSHA) curve.
The Design Engineer shall provide a hydraulic profile of the entire pump station/forcemain system,
and this profile shall show the hydraulic grade-line from the pump station to the discharge location(s).
Where the forcemain contains intermediate high points, the Design Engineer shall analyze if this point
becomes the controlling discharge elevation under certain flow conditions. The Design Engineer shall
provide detailed calculations to the City for information and review.
6.4.1.3 Pump Curves
Once the system curve is developed, several types of pumps can be analyzed to ascertain which pump
curves best fit the system curves. Most manufacturers provide pump curves with the total dynamic
head (TDH), efficiency, Net Positive Suction Head Required (NPSHR), and power input plotted against
the flow rate. Pump curves shall be defined by: design point, reduced speed design point (where
applicable), shut-off head, and run out point. These pump manufacturer curves can be plotted against
the system curve to verify the pump’s operating region. Pumps with steeper curves shall be selected
over pumps with relatively flat curves. Additionally, the most efficient pump shall be considered.
In cases where multiple pumps are required to produce the necessary flow at the required head,
parallel pumping curves shall be generated and verified against the system curves. This exercise must
be performed for new designs as well as modifications to existing lift stations. The pump selection
comprising pump type, manufacturer, model number, size, impeller size, flow in gpm, TDH, efficiency,
Net Positive Suction Head (NPSH), Horse Power (HP), Revolutions Per Minute (RPM) and pump head
curves plotted with the system head curves and calculations for each pump must be submitted to the
City for review. The total cycle times for Average Daily Flow (ADF) and Peak Hourly Flow (PHF)
(number of minutes “on” and “off”) shall also accompany the submittal.
If Variable Frequency Drives (VFDs) are used, the engineer shall prepare reduced frequency curves.
Curves shall be provided for the following percentages of full speed: 100, 90, 80, 70, and 60. It is
recommended that pumps not be operated on VFDs below 40 percent of its rated speed to prevent
recirculation and churning. The minimum flow rate at which the pump is capable of continuously
pumping wastewater should also be identified.
6.4.2 Force Main The Design Engineer shall refer to Section 4.3.1 Wastewater Force Mains for guidelines and other
design considerations.
6.5 Submersible Sewage Pump Station A submersible sewage pump station includes a wet well, submersible pump(s), valves and an
electronic pump control system. The wet well for submersible pump should follow the procedures
outlined in Section 6.3. Regardless of the capacity of the wet well, the wet well configuration and
placement and spacing of the pumps shall comply with the Hydraulic Institute guidelines to prevent
turbulence and vortexing at the pump inlet.
Section 6 Wastewater Lift Station Design
6-5
6.5.1 Construction Submersible pumps and motors shall be designed specifically for raw wastewater use, including
totally submerged operation during a portion of each pumping cycle and shall meet the requirements
of the National Electrical Code (NEC) for such units. An effective method to detect shaft seal failure or
potential seal failure should be provided. Small pre-fabricated submersible pump stations are
available with pumps, and motors pre-configured into a single well. Where possible such pre-
fabricated pump stations shall be used.
All fixtures and fasteners, including guide rails and brackets shall be constructed of Type 316 stainless
steel. Aluminum access hatch(es) with safety grating must be provided above the pumps in the top of
the wet well, and for the valve and flowmeter vaults, and shall have adequate clearance to safely and
easily remove the pumps.
6.5.2 Wet Well Coatings The interiors of the lift station wet well shall be coated or lined using an appropriate coating or lining
material to the required thickness as detailed in the City’s Standard Specifications and shall be
completely resistant to hydrogen sulfide and sulfuric acid. Coating or lining materials shall be subject
to the approval of the City.
6.5.3 Removal of Submersible Pump These pumps shall be capable of being removed or replaced without the need for: personnel to enter
the wet well, dewatering of the wet well, or disrupting any piping in the wet well, so as to maintain
continuity of operation of the other units. The access hatches shall also be adequately sized to meet
these requirements.
6.5.4 Electrical Equipment Electrical systems and components such as control and alarm circuits must be designed to provide
strain relief, and to permit disconnection from outside the wet well. Terminals and connectors must
be protected from corrosion by location outside the wet well or through use of watertight seals. Three
phase power shall be used where available.
The Control Panels shall be enclosed in Type 316 Stainless Steel NEMA 4X enclosures and shall include
adequate space for mounting of the controls and instrumentation as required. The motor control
center should be located in a clean dry area, be readily accessible and be protected by a conduit seal or
other appropriate measures meeting the requirements of the National Fire Protection Association
(NFPA) Code 820 for Wastewater Facilities, to prevent the gases prevalent in the wet well from
entering the control center. The seal shall be located in a manner such that the motor may be
removed and electrically disconnected without disturbing the seal. When such equipment is exposed
to weather, it shall meet the requirements of weatherproof equipment (NEMA 3R or 4). Electrical
design shall include lightning and surge protection.
The main breaker shall be a NEMA 4X enclosure, and shall include a minimum of sixteen (16) breaker
spaces, sized in accordance with the lift station capacity, and other electric connections to be installed
on site. Individual connections shall be powered by separate breakers (ex: lights, and radio shall be
powered by two separate dedicated breakers). The main breaker shall meet the requirements of the
NEC.
Section 6 Wastewater Lift Station Design
6-6
Pump motor power cords shall be designed for flexibility and serviceability under conditions of extra
hard usage and shall meet the requirements of the NEC standards for flexible cords in wastewater
pump stations. Ground fault interruption protection will be used to de-energize the circuit in the event
of any failure in the electrical integrity of the cable. Consider base flood elevations when locating
electrical equipment. Special consideration should be given to the power cord insulation to verify it
can with stand the wet well gases, including odor control chemicals/equipment.
Power cord terminal fittings shall be corrosion-resistant, and constructed in a manner to prevent the
entry of moisture into the cable, shall be provided with strain relief appurtenances and should be
designed to facilitate field connections. Design for lift stations without buildings shall include covers
for electrical, telemetry and control units. Covers shall be rated for outdoor service and shall include
sunshields to facilitate easy reading of Light Emitting Diode (LED) displays. Equipment placed
outdoors shall be rated for such service and shall be sized for ambient temperatures and cooling
requirements.
6.5.5 Valve Vaults Separate valve vaults may not be required for packaged lift stations that include their own valve
enclosures, the Design Engineer shall check manufacturer requirements during design to confirm
location of valves. For all other lift stations, required valves should be located in a separate valve
chamber, valves shall not be located inside the wetwell. Provisions shall be made to remove or drain
accumulated water from the valve chamber. The valve chamber may be dewatered to the wet well
through a drain line with a gas and water tight valve.
Valve vaults shall be sized to accommodate the force main pipe size, and associated valves and fittings.
A minimum 2 feet clearance between inside walls of the vault and all valves/fitting shall be provided.
6.6 Dry Pit Pump Station The Wet Pit of this type of station is the wetwell. The wetwell contains the level control and suction
piping for the pumps. The dry-pit including the superstructure shall be completely separated from the
wet well. Common wall must be gas tight. Each pump must have individual suction pipe to the wet
well. Isolation valves should be located both between the pump and the wet well and downstream of
the discharge check valve. At a minimum, pumps and its appurtenances shall be designed to withstand
pumping conditions (ex: grit, solids, rags), service conditions (ex: presence of H2S gases, highly
corrosive sewers). Pump shall also be equipped, at a minimum, with suitable coatings, moisture
detectors, temperature detectors, appropriate seals, and wear rings (where required).
6.7 Valves for Pump Stations The configuration of valves is dependent upon the lift station’s design capacity. Suitable isolation
valves shall be placed on the pump suction and discharge lines where appropriate. Check valves shall
be placed on the discharge line of each pump. The isolation valves shall be full port eccentric plug
valves with elastomeric-coated plug and lever operators. Eccentric plug shaft shall be installed
horizontally, with plug stored in the top position when valve is OPEN, to minimize potential for grit
accumulation in valve seat or shaft bearing. Valves shall be laid such that the plug is on the “top” of the
body when fully opened. Only full-body flanged check valves shall be used. Cushioned swing-type
check valves with an outside lever and spring or weight unit shall be provided, so operators can see
which valves are OPEN. Flow velocities through check valves shall not exceed 10 fps. Check valves
shall be mounted at elevations that permit servicing from the floor without scaffolds or ladders. All
Section 6 Wastewater Lift Station Design
6-7
valves shall be shown on the drawings, and shall be of the same size as the pipe in which the valve is
situated, unless otherwise noted. Valves shall be capable of withstanding test pressures (usually 1.5
times the working pressure) and the pressure generated by a water hammer.
Electric operators shall be provided for valves 20 inches and larger. The operators shall include local
OPEN/CLOSE controls that can be secured to prevent unauthorized operation of the valve.
6.8 Air Release Valves Air relief, air-vacuum release, or combination air release and vacuum valves shall be of a type and
brand manufactured for wastewater service, and shall be provided at critical locations in the pump
station and force main. The valves shall serve to prevent air being captured inside the piping system,
or prevent collapse of the piping system due to vacuum conditions. Each valve shall be sized with the
adequate orifice size suitable for the volume of air to be admitted or released. Each valve shall be
provided with an isolation valve. An insulated coupling, ball valve, and pipe union shall be provided on
each assembly to allow maintenance and removal of the air valve. The air-release valve discharge
piping in pump stations shall be piped to the station’s wet well.
6.9 Emergency Bypass Connection The Design Engineer shall design the lift station piping to permit an emergency bypass connection to
allow pumping of the lift station wet well in case of total pump station failure. The connection shall
include a quick connect coupling for connection to the emergency bypass pump. Bypass connection
shall be designed with an isolation valve. Locate bypass connection so as to provide ample space for
access by bypass trucks/trailers.
6.10 Flowmeter Magmeter shall be located in the superstructure of dry pit pump stations, or in a dedicated concrete
vault in case of wet pit pump stations. The magmeter display shall be located in the superstructure for
dry pit pump stations. Displays placed in the open shall be housed in an assembly that includes a
sunshield. The Design Engineer shall locate the magmeter such that all manufacturer recommended
upstream and downstream clearance requirements are met, while maintaining sufficient clearance for
maintenance operations. All magmeter installations shall include digital display/readout to indicate
flows in gallons per minute (gpm), signal from the magmeter shall be transmitted to the SCADA as
indicated elsewhere in this document. Magmeters are to be located such that they are not installed on
downcomer pipes.
6.11 Pressure Gauges All new pump stations shall include a suction (where possible) and discharge pressure gauge suitable
for wastewater service. Pressure transducers (also known as pressure transmitters) shall be used in
pump stations where it is required to transmit pressure readings to the City’s SCADA system.
6.12 Hoisting and Lifting Equipment For pump weighing 1.5 tons and above, include in design, a means for the removal of pumps and other
heavy equipment located at the pump station in coordination with the City’s Wastewater and
Sewerage personnel. Lifting equipment shall be sized to remove the heaviest equipment with a 2x
safety factor. Lifting distance (height) shall account for complete removal and loading of the
Section 6 Wastewater Lift Station Design
6-8
equipment on a truck bed. Lifting mechanism shall be completely motorized and shall be in
accordance with the City’s Standard Specification Section 2800.
6.13 Odor Control When designing odor control system for the lift station, the Design Engineer shall obtain all relevant
data from the City (if available), previous studies (if available) or by field measurement. In general,
odor control systems are to be designed to lower the Hydrogen Sulfide (H2S) concentration to meet
Department of Health and Hospitals’ (DHH)permit requirements. Various techniques and
methodologies are available to achieve odor control as listed in the EPA’s design manual – ‘Odor and
Corrosion Control in Sanitary Sewerage Systems and Treatment Plants’. All relevant calculations shall
be documented in the Design Criteria Report.
For lift stations that will be operated infrequently, incorporate a compressed air system (with
diffusers), in consultation with the City, to effect odor control. The air pump flowrate, in cubic feet per
minute (CFM) shall be sized based on the volume of the sewer in the wetwell to be mixed. The Design
Engineer shall use a mixing air flow rate of 20 CFM/1000 Cu.Ft to 30 CFM/1000 Cu.Ft as
recommended by the Ten States Standards. The pressure rating for the air pump shall include head
losses in the piping/tubing, losses due to fittings, valves, air filters etc., and the water level in the
wetwell. The diffuser for such systems shall be located at appropriate locations to minimize air
entrainment into the pumps. The air pump assembly, including its filters, silencers etc. shall be housed
in a suitable enclosure.
For all other lift stations, the Design Engineer shall recommend a suitable odor control technology or
methodology based on controlling parameters for each lift station, commonly accepted engineering
practices, past experiences, and City preferences.
6.14 Pump Station Emergency Operations 6.14.1 General The design engineer must evaluate the need for backup power at a wastewater lift station for each
specific location. The aim of emergency operation is to prevent the discharge of raw or partially
treated sewage to any waters and to protect public health by preventing backup of sewage and
potential discharge to basements, streets and other public and private property. The Design Engineer
shall discuss the need for, and type of emergency pumping equipment with the City’s Water and
Sewerage personnel during design.
6.15 Lift Station Controls Lift Station controls shall be based on the pump size (Hp) as listed in Table 6-1. This classification
system is not universal and its usage is limited to this manual, and other pertinent documents (ex: lift
station specifications). The Design Engineer shall consult the City, and incorporate the City’s control
system protocol when updating /editing specifications for lift stations and control systems.
Table 6-1 Lift Station Size Classification
Individual Pump Size (Hp) Lift Station Classification
< 15 Hp Small
≥15 Hp < 25 Hp Medium
≥25 Hp Large
Section 6 Wastewater Lift Station Design
6-9
Various control elements for the lift stations are detailed in Table 6-2.
Table 6-2 Lift Station Control Elements
Lift Station Controls Small Lift Station Medium Lift Station Large Lift Station
VFD SC IN Y
Float Ball Controls Y Y N
Float Ball Backup System SC IN Y
Human Machine Interface (HMI) SC IN Y
Programmable Logic Control (PLC) SC IN Y
Soft Starts Y Y N
SC – Special Cases only. Provide written justification for City review; IN – If Needed. Based on Design Engineer’s
evaluation and recommendations; Y – Yes; N - No
6.15.1 HMI Signals and Alarms Signals and alarms at each lift station vary based on the lift station size. See Table 6-3 for HMI signal
and alarm parameters. Alarms shall be transmitted to the operations staff by means of the radio
telemetry system. Consult City during design to finalize outputs to the SCADA system.
Table 6-3 Lift Station HMI Signals and Alarms
HMI Signals And Alarms Small Lift Station Medium Lift Station Large Lift Station
Operation Mode (primary/ backup) SC IN Y
Level And Alarm Set Points SC IN Y
Pump Current (amps) SC IN Y
Pump Speed (Hz) SC IN Y
Pump Run Time (Hours) Y Y Y
Hand/Off/ Auto operation Y Y Y
Pump Over Temperature Y Y Y
Pump Moisture Sensor Y Y Y
Pump Overload Y Y Y
Seal Water System (If applicable) Y Y Y
Wet Well Level SC IN Y
Alarm History SC IN Y
High Wetwell Level Y Y Y
Low Wetwell Level Y Y Y
Flowmeter Reading SC IN Y
Pressure Transmitter Reading (psi) SC IN Y
Primary Power Fail Y Y Y
Sump Pump Status IN IN IN
High Sump Alarm IN IN IN
Intrusion Alarm (where applicable) Y Y Y
SC – Special Cases only. Provide written justification for City review; IN – If Needed. Based on Design Engineer’s
evaluation and recommendations; Y – Yes; N - No
6.15.2 Telemetry System 6.15.2.1 General
Include Remote terminal units (RTUs) for each lift station in the system. The City prefers that RTU and
associated SCADA equipment are from a single manufacturer or vendor.
Section 6 Wastewater Lift Station Design
6-10
6.15.2.2 Hardware
The master, and the RTUs will be the same hardware with I/O selected per device. The unit shall be
field expandable for the addition of alarm, status, control and analog inputs and/or outputs. All
firmware shall be non-volatile (memory) with automatic restart after power failure. An on board
watchdog timer shall be included.
Basic input/output capabilities of the unit shall include ten (10) digital inputs, ten (10) digital outputs,
four (4) analog input and two (2) analog outputs. Digital input shall be optically isolated and meet
IEEE 2.5KV surge suppression. Digital outputs shall be Relay Form A250 VAC, 6 Amp load; 125 VAC;
20 VDC, 5 Amp load @ 30 VDC. Interface of digital output to field devices shall be through isolated
relay contacts. Contacts shall be rated for 3 amperes at 240 VAC.
The RTU shall consist of the following:
1. NEMA 4X Stainless Steel Enclosure
2. Control Power Circuit Breaker
3. Controller with 3 communication ports
4. RADIO as recommended by SCADA Consultant
5. Power supply with battery backup for 8 hours
6. TVSS on Incoming service
7. Lightning Protection for antenna
6.15.2.3 Diagnostics
Include internally mounted Light Emitting Diode (LEDs) for indication of power on, CPU run, carrier
detect, receive data, request-to-send and transmit data.
6.15.2.4 Requirements of Power
The RTU will be powered by a 12-volt power supply. A sealed 7 Amp/Hr gell cell 12-volt battery and
charger will be supplied to power the entire RTU during emergency power outage conditions.
6.15.2.5 Communications
The SCADA System shall be capable of supporting Ethernet connectivity and TCP/IP communication
protocols.
6.15.2.6 Radio System
The telemetry signals shall be transmitted/received over a radio system operating in a half-
duplex mode on a single VHF Frequency Modulation (FM) radio frequency.
The radio telemetry system shall include an antenna for each site as required to achieve the
overall communications requirements of the system. Antennas shall be directional or omni-
directional as required and suitable for outdoor environments. They shall be of all aluminum
construction and rated to withstand as least 100 MPH winds with ½ inch radial ice.
Section 6 Wastewater Lift Station Design
6-11
Adequate lengths of RG213A/U coaxial cable shall be provided for connection of the antenna to
the radio transceiver at each site. Splicing of cable shall not be allowed. The transmission line
shall be terminated only in connectors rated for the required service. A lightning arrestor shall
be placed between the transceiver and coaxial cable.
Unless specifically stated, the antennas shall be attached to a separate pole. Particular attention
shall be given to the correct installation of the antennas to give adequate protection from
nearby lightning strikes by providing a low resistance DC path to ground. Instructions for
installing these antennas shall be given to the contractor to facilitate reliable operation.
Design shall include mounting masts or poles as required to support the antennas at the
elevations and orientations required. Masts and poles shall be suitable for outdoor
environmental conditions, provide adequate support and protection for transmission lines and
shall be complete with all necessary mounting accessories.
Consult the City’s Water and Sewerage personnel regarding preferred radio systems.
Minimum acceptable technical and physical specifications of the directional antenna shall be as
follows:
Type: 3 element Yagi, with a forward gain of at least 10 dB
Front to back ratio: 20 dB
Lightning Protection: Direct ground
Feed point method: Weatherproof gamma match for coaxial feed line
6.15.2.7 RTU Outputs to SCADA
Lift station RTU Outputs to the City’s SCADA system shall also be based on the lift station size. See
Table 6-4 (below) for RTU outputs. Consult City during design to finalize outputs to the SCADA system.
Table 6-4 Lift Station RTU Outputs
RTU Outputs Small Lift Station Medium Lift Station Large Lift Station
Wet Well Level (Analog) SC IN Y
Pump Current (analog) SC IN Y
Pump Speed (analog) SC IN Y
Flowrate (analog) SC IN Y
Discharge Pressure (psi) SC IN Y
Power failure (digital) Y Y IN
Pump running (digital) SC IN Y
Pump run time (hours) SC IN Y
Pump Over Temperature (digital) SC IN Y
Moisture Sensor (digital) SC IN Y
Motor Overload (digital) SC IN Y
VFD fault SC IN Y
Pump in ‘Auto’ (digital) SC IN Y
Wet well transmitter failure (digital) SC IN Y
High level alarm (digital) Y Y Y
High sump alarm (digital) IN IN IN
Section 6 Wastewater Lift Station Design
6-12
RTU Outputs Small Lift Station Medium Lift Station Large Lift Station
Float position- High wetwell level SC IN Y
Float positions - Low wetwell level SC IN Y
Operations on float ball backup (digital) SC IN Y
Communication status (digital) Y Y Y
Intrusion alarm status (digital) Y Y Y
SC – Special Cases only. Provide written justification for City review; IN – If Needed. Based on Design Engineer’s
evaluation and recommendations; Y – Yes; N - No
6.16 Lift Station Siting and Access Lift stations shall be located in public right-of-way or in a dedicated servitude on property owned by
the City or property donated to the City, such that they are easily accessible by the City maintenance
vehicles and supply trucks; and as far as possible from residential areas. Locate lift stations at a
minimum of 150 feet away from any existing or proposed residential dwelling.
Lift stations shall be served by a permanent access road that is located in the public right-of-way. For
lift stations with onsite chemical storage for odor control, access roads shall be designed to provide
sufficient turning radius for chemical supply trucks. The finished access road shall be constructed with
at least 3 inches of asphaltic concrete with a crushed aggregate base, or 8 inches of concrete with a
crushed stone base, or crushed rock as approved by the City. Base material and compaction
requirements for the access road shall be based on geotechnical information for the site. The access
road must be located above the 25-year flood elevation.
The site shall be located a minimum of 2 feet above the 100-year flood elevation, and shall be designed
with site grading devised to prevent storm/rain water ponding or erosion. Areas immediately
adjacent to the lift station shall be graded such that storm water doesn’t run across the lift station or
deposit runoff or debris on the lift station. Design all electrical and instrumentation control panels to
be mounted a minimum of 3 feet above the 100-year flood elevation.
A potable water line with a freeze proof hose bib shall be provided within the lift station premises. The
water line shall be designed with a suitable backflow prevention device, and shall be located a
minimum of 25 feet away from the outer wall of wetwell.
The lift station site shall be secured by a fence with gate(s) suited to the locality (ex: decorative
fence/wall for a lift station located in a City park), therefore type of fence and gates shall be decided in
consultation with the City.
7-1
Section 7
Water Distribution Mains
7.1 Potable Water Design Flows The City’s water system should be able to supply water at all times, at rates that oscillate over a wide
range during different hours of the day, and times of year. Per capita usage can fluctuate considerably
depending on the type of population served (Industrial/Domestic/Commercial). The most important
flows pertaining to the design of a potable water system are as follows.
7.1.1 Annual Average Daily Flow The annual average daily Flow (AADF) is the total quantity of flow delivered each day to the water
distribution system in a year divided by the number of days in a year, usually 365 days.
7.1.2 Peak Daily Flow The peak daily flow (PDF) is the maximum quantity of water that can be used in any day of the year. It
is also referred to as maximum daily flow. Raw water transmission and water treatment facilities are
typically sized to meet the peak daily demand.
7.1.3 Peak Hourly Flow The peak hourly flow (PHF) is the quantity of flow delivered during the highest water use hour.
7.1.4 Water Main Sizing Water mains and extensions shall be sized to accommodate the sum of peak daily demand (typically
between 1.5 to 1.8 times AADF) and fire flow demand or peak hour demands (typically between 2.0 to
3.0 times AADF), whichever is larger.
7.2 Fire Flow Fire flow (FF) is the amount of water available in the system for combating a fire at designated
locations throughout the community. The minimum fire flow rate, pressure and duration shall be
estimated based on the information from Fire Marshall’s office or the Insurance Services Office (ISO)
guidelines.
7.2.1 Peak Flow The peak flow (PF) is the ultimate flow that can be delivered into the system instantaneously. It shall
be the sum of peak daily flow plus the fire flow rate (PF = PDF + FF) or the PHF, whichever is greater.
7.3 Transmission Mains and Distribution Mains Transmission lines are conduits that carry large volumes of water from one point to another without
intermediate service connections. Distribution mains are smaller pipelines that deliver treated
potable water to the customers.
Section 7 Water Distribution Mains
7-2
For the purposes of this manual, all water mains in the City‘s system that are 16 inches and larger in
diameter are categorized as transmission mains. All water mains 14-inches and smaller in diameter
are classified as distribution mains.
Service connections on transmission mains are prohibited unless approved by the City. Approved taps
on transmission mains shall be a minimum of 2 inches in diameter.
7.4 Water System Pressure The normal working pressure within the distribution system should be approximately 75 psi and not
less than 35 psi. A minimum residual pressure of 20 psi shall be maintained at ground level at all
points in the distribution system. Higher pressures may be required at commercial, industrial, or
high-density residential areas.
7.5 Water System Design Calculations The Design Engineer must clearly state in the Design Criteria report, all design flows and pressure
conditions. The design calculations submitted to the City shall include:
The population used in the design
Annual Average daily flow (AADF)
Peak daily flow (PDF)
Peak hourly flow (PHF)
Peaking factors
Fire flow
Pipe size
Velocity, and
Minimum residual pressure
The City may provide a connection pressure at a set point along the existing system near the proposed
development. All hydraulic calculations shall be based on the connection pressure provided by the
City. When such information is not readily available, the Design Engineer shall rely on field data or
shall back calculate this information based on available information and accepted engineering
standards. Such data sources or assumptions shall be clearly stated in the design calculations. Head
losses through meters and backflow devices shall also be included in the calculations.
When available, the City may provide modeling support to review the design (in terms of flows and
pressures). Model computations, if performed by the Design Engineer, shall clearly be presented in a
tabular format showing system pressure, demand nodes and other pertinent information on plot(s)
that are legible. All important nodes shall be annotated to identify water demand. Both peak hour and
peak daily plus fire flow scenarios must be presented.
Section 7 Water Distribution Mains
7-3
7.6 Water Main and Extension Location See Figure 2-1 in Section 2 for a guidance schematic.
7.6.1 Residential (service) Water Line Locate water lines for residential services minimum of five (5) feet away from existing or proposed
utilities, mailboxes, and other permanent structures. Service lines shall be straight connections from
water mains and shall not be encased in concrete. Service lines shall not be located beneath private
driveways or walkways. Water meters shall be located at the property line, in the utility servitude,
close to the right-of-way to allow for easy access. Water meters shall not be located beneath or
enclosed in fences, walls or decorative structures.
7.6.2 Normal Water Main Location Water mains shall be located on the North (streets oriented East-West) or West (streets oriented
North-South) side of the street. Water mains shall be located in the public right-of-way, at the center of
a 20 feet wide (minimum) water servitude. Minimize servitude overlap on private property.
Dedicated servitudes on private property shall be considered only when there are limitations in
locating the water main in the public right-of-way, submit written documentation for City review and
approval. Limit water main deflection to 50% of the manufacturer’s recommendations. Water lines
shall be extended to the furthest property line to accommodate future expansion and development.
7.7 Water Main Separation Requirements 7.7.1 Horizontal Separation from Sanitary Sewer Mains Water mains shall be laid horizontally, a minimum of 10 feet, from any point of existing or proposed
sewer. The minimum distance shall be measured edge to edge. Water mains and sanitary sewer shall
not be installed in the same trench.
Where water mains and sewers follow the same roadway, they shall be installed on opposite sides of
the roadway.
7.7.2 Vertical Separation A minimum of 18-inch vertical clear separation between water mains and sanitary sewers is required.
This distance should be measured from the outside diameters of the pipes. At all crossings, the water
main shall be encased in concrete. When local conditions prevent a minimum vertical clearance
between crossing pipes then sewer line shall be constructed of ductile iron pipe conforming to ASTM
A536 or ANSI/AWWA C151/A21.51. for a minimum distance of ten (10) feet in each direction from
the crossing with the sewer pipe joints arranged as far as possible from the water main joints. The
Design Engineer shall also obtain a variance permit from the DHH.
7.7.3 Separation from Storm Drains and Other Utilities Water mains shall maintain a minimum of six (6) feet horizontal separation from storm drains and
culvert and other utility lines. The water main shall maintain a minimum of two (2) feet vertical
separation from storm drains, culverts, and other utility lines. Water mains crossing less than two (2)
feet (upon DHH approval) below a storm drain or culvert shall require additional protection such as
the use of ductile iron pipe and pipe casing.
Section 7 Water Distribution Mains
7-4
7.7.4 Separation from Sewer Manholes No water pipe shall pass through or come in contact with any part of a sewer manhole. Water mains
shall be located at least 10 feet from sewer manholes.
7.8 Water Main Diameters Only, 8, 10, 12, 16, 20, 24, 36, 42 and 48-inch diameter water mains shall be permitted. Pipe materials
for water mains and extensions shall be PVC or DIP depending on the location, use, size and approval
by the City. The Engineer shall submit in written justification, for the City’s review and approval, to
use other piping material. Such pipe material shall be sized to match the internal diameter of the
required PVC or DIP pipe.
7.9 Water Main Looping and Deadends To provide increased service reliability and to reduce head loss, dead ends shall be minimized by
making appropriate tie-ins whenever practical. Water mains shall be looped, if possible, to avoid dead
ends. In cul-de-sacs the water main shall be curved along the cul-de-sac/right-of-way, and the dead
end shall be located at the end of the curve.
All mains with dead ends shall be equipped with a fire hydrant 10 feet away from dead end (see Figure
7-1 below). Dead end lines for future expansion will require a master development plan to verify and
support sizing of the water main.
Figure 7-1 Cul-De-Sac Dead Ends
Notes:
1) This drawing is normally for streets oriented East-West. Flip drawing 90 degrees counter-clockwise for streets oriented North-South.
Section 7 Water Distribution Mains
7-5
2) Water mains shall be located in public Right-Of-Ways. 3) Locate a fire hydrant 10 feet away from the dead end.
7.10 Potable Water Valves A sufficient number of valves shall be provided on water distribution and transmission mains to
minimize inconvenience and sanitary hazards during repairs. Valves shall be located at not more than
500 feet intervals in commercial, industrial, and business areas, and at not more than 800 feet
intervals in all other areas. Appropriate valving shall also be provided at all areas where water mains
intersect in order to provide effective isolation of water lines for repair, maintenance, or future
extension.
Valves shall not be installed in pavement unless specifically approved by the City. Valves shall also be
installed at all fire hydrant locations for ease of locating. Refer to Section 9 of this document for more
details.
7.11 Water Main Cover Use a minimum cover of five (5) feet over the top of the pipe for all water mains.
7.12 Surface Water Crossings for Water Mains Surface water crossings are to be avoided if possible. Consult City regarding surface water crossings
before final plans are prepared.
7.12.1 Above Grade All above grade water crossing pipelines must be adequately supported on an acceptable
foundation/support. Piping shall be ductile iron. Plans must be signed and sealed by an engineer
registered in the state of Louisiana. The installation must be protected from damage and must be
accessible for repair or replacement. Valves shall be placed at both ends of the water crossing at the
normal main depth, so that section of main can be isolated. A combination air release/vacuum valve
and crossing guards shall be provided. All above grade ductile iron piping shall be painted. Aerial pipe
crossings are further discussed in Section 12 of this manual.
7.12.2 Below Grade A minimum of five (5) feet shall be maintained from the top of water main to the design bottom
elevation of the open canal/ditch for below ground piping.
Sub-aqueous pipe crossings shall be horizontal directionally drilled using HDPE or fused PVC
pipe. In cases where the crossing is greater than 1,000 feet, a steel casing will be provided. For
water courses greater than fifteen feet in width, the water main shall be designed with flexible,
restrained or welded watertight joints.
Valves shall be provided at both ends of water crossings so that the section can be isolated for
testing or repair. The valves shall be easily accessible, and not subject to flooding. Additional
details pertaining to stream crossings can be found in Section 13 of this manual.
Section 7 Water Distribution Mains
7-6
7.13 Roadway Crossings for Water Mains All water mains crossing major City roadways shall be bore and jacked or horizontally drilled. Open
trench installation is feasible at low traffic locations, the City shall be consulted prior to selecting the
method of crossing.
7.14 Air Release Valves and Blow offs for Water Mains 7.14.1 Air Valves Air valves shall be installed at high points along the water main to purge air from the line continuously
and to prevent vacuum formation during water main draining. The crown of the air valve vent shall be
located a minimum 6 inches above the base flood elevation. Further information regarding these
valves can be found in Section 9.2 of this manual.
7.14.2 Blow offs Blow off assemblies (or flush valves) shall be installed at low points of the water main to allow
periodic flushing of the mains. Where possible, fire hydrants shall be utilized in place of blow offs.
Blow off assemblies shall be located as close as possible to drainage ditches to prevent erosion and
ponding of water along roadways or streets. Automatic flush valves shall be used where requested by
the City.
7.15 Disinfection Requirements New, cleaned, and repaired water mains shall be disinfected as outlined in the City’s Standard
Specifications.
7.16 Existing Water Mains All existing mains shall be relocated, and installed as new mains if the existing mains are in the right-
of-way that fall under pavement.
Split casings can be utilized for existing mains that fall under new pavement that are perpendicular to
the main.
All main relocations shall be implemented with none or minimal interruption of service. Construction
that requires interruption of service shall be planned and scheduled at low peak demand hours or as
found acceptable by the City.
7.17 Thrust Restraints Refer to Section 4.5 of this manual.
7.18 Water Main Servitudes for Construction and Maintenance The Water and Sewerage Department requires safe and rapid access to all City water mains at all
times to repair main breaks, install taps, and perform preventive maintenance. For this reason, the
City‘s water mains shall be constructed within the street right-of-ways.Backlot or sidelot servitudes
will not be allowed.
Section 7 Water Distribution Mains
7-7
7.18.1 Servitude All water pipelines shall be constructed in public rights-of-way, wherever feasible or in public water
main servitudes, when conditions dictate. If it is determined that infrastructure improvements must
be performed outside of existing right-of-way or existing servitudes, then it is necessary to obtain the
City’s approval for a new servitude, and the process must be started as soon as an approved pipeline
alignment has been decided upon in order to avoid delay in construction plan approval.
7.19 Service Connections 7.19.1 Service Connection Materials and Sizes Copper tubing shall be used for all water service lines three quarters of an inch (3/4") through two
inches (2”) in diameter. Material requirements for water service lines larger than two inches (2”) in
diameter shall be approved PVC or ductile iron pipe. Buried service connection pipe shall be designed
for a minimum pressure class of 250.
The service connection shall be as per the City’s Standard Specification Sections 209 and 3200.
7.20 Fire Code All systems requiring fire protection shall be designed such that fire flows and facilities are in
accordance with the requirements of Chapter 30 – Fire Prevention and Protection, Article III, Fire
Prevention Standards of the City of Shreveport Code of Ordinances.
7.21 Plumbing Code Water service and plumbing shall conform to the Chapter 22 – Buildings and Building Regulations of
the City of Shreveport Code of Ordinances and Louisiana State Plumbing Code(Part XIV (Plumbing) of
the State Sanitary Code).
Section 7 Water Distribution Mains
7-8
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8-1
Section 8
Fire Hydrants
8.1 General Location and Design Requirements Locate fire hydrants to facilitate quick access and use by the Fire Department. The Design Engineer
shall use engineering judgment, and common sense to locate the fire hydrant(s) such that it is in a
visible, and predictable location based on the type of development, with unobstructed accessibility to
meet the Fire Department’s needs . Minor variances in the locations or spacing of individual hydrants
may be approved, provided the functional intent of these design standards is achieved. The Design
Engineer should:
Provide fire hydrants at each street intersection and at intermediate points between
intersections as recommended by the fire chief.
Locate fire hydrants where they are readily visible by fire engines traveling along the street or
approaching on intersecting streets. Never obscure or obstruct hydrants behind fences, gates,
walls or landscaping.
Specify fire hydrant top colors in accordance with National Fire Protection Association’s
(NFPA) guidelines, as stated in NFPA 291.
Provide fire hydrants at street intersections and at the main entrance into a subdivision,
apartment complex or commercial development. Additional hydrants must be provided at a
spacing based on maximum spacing between hydrants. Spacing is measured along the route of
travel of a fire engine.
Provide fire hydrants at all dead ends in the water distribution system.
Locate fire hydrants such that, they are not placed within 3 feet of an above ground
obstruction and maintain 18 inches of clearance between the ground and the lowest hydrant
outlet cap. Hydrants shall be located within water servitudes providing at least 6 feet of
clearance on all sides of the hydrant, including protective bollards as directed.
Consider drainage arrangements/requirements during design of fire hydrants.
Size fire hydrants capable of a minimum flow of 600 gpm.
Specify a minimum of three, equally spaced, blue colored reflective strips, in the street or
paving adjacent to the fire hydrant for easy location at night.
Include a 6 inch operating valve (minimum).
Design/call out fire hydrants in accordance to City of Shreveport’s Standard Specifications.
Section 8 Fire Hydrants
8-2
8.2 Residential Subdivision Hydrant Location Standards Fire hydrant locations will be reviewed and approved as part of the subdivision approval process. The
Design Engineer should follow the General Location and Design Requirements as stated in Section 8.1
and:
Shall locate a fire hydrant at the intersection of each public and/or private street entrance into
the subdivision unless an existing fire hydrant meets spacing requirements.
Space additional fire hydrants 500 feet apart along all public and/or private streets within the
subdivision and along all perimeter streets.
For cul-de-sacs:
- Space fire hydrants 500 feet apart. As stated previously, a fire hydrant shall be located 10
feet away from dead ends.
8.3 Commercial and Multi-Family Hydrant Location Standards Fire hydrant locations will be reviewed and approved as part of the site plan/building permit approval
process. Provide a site plan showing all existing and proposed fire hydrant locations, all designated
fire lanes, and all Fire Department Connections (FDC’s) for building standpipe or sprinkler systems.
Whenever possible the Design Engineer shall locate hydrants with a setback of at least 40 feet from
the building.
Follow the General Location and Design Requirements as stated in Section 8.1 and:
First, determine whether new fire hydrants are required. New hydrants are not needed if existing
hydrants are close enough to provide the required coverage:
Within 500 feet of the most remote building corner or the most remote hazard on site,
measured as the hose lays along designated fire lanes or other clear access routes (within 500
feet of the most remote corner of fire sprinkled buildings)
Within 200 feet of all FDC’s for sprinkler and standpipe systems.
If existing fire hydrants do not provide the required coverage, new hydrants must be added as follows:
Locate a fire hydrant at the main entrance (driveway) into the development and at other
entrances identified as fire apparatus access roads (fire lanes).
Additional hydrants shall be spaced approximately 500 feet apart along all public roads and
along all designated fire lanes.
8.4 Private Fire Hydrants Private hydrants are those hydrants located on private property and/or connected to any water line
not owned and maintained by the City. In addition to compliance with NFPA 291, private fire hydrants
shall have their bonnets painted reflective white to identify them as privately owned and maintained.
The property owner is responsible for maintaining all private fire lines and fire hydrants in working
order at all times.
Section 8 Fire Hydrants
8-3
8.5 Maximum Fire Hydrant Spacing Table 8-1, lists the maximum spacing for fire hydrants for different land uses. Spacing distance shall be
measured along the centerline of the street or route, which the fire truck will most likely travel.
Table 8-1 Fire Hydrant Spacing
LAND USE SPACING REQUIREMENTS FIRE HYDRANT MAXIMUM SPACING (feet)
Single Family Residential 500
Two Story Townhouses and Apartments 300
Commercial and Industrial (including
Shopping Centers) 300
Off-site main extensions adjacent to undeveloped property
1000 or as required by the City of Shreveport
Cul-de-Sacs 500, to include hydrant within 10 feet of pipe end
8.6 Fire Hydrant Relocations Every attempt shall be made in the design phase of the projects to locate driveways outside of existing
fire hydrant locations. In the event that a hydrant must be relocated, the existing service line and valve
should be cut and removed from the existing water main and a new section of pipe installed with a
restrained flexible coupling. A new fire hydrant service line shall be installed perpendicular to the new
hydrant location.
In circumstances where the relocation of the existing hydrant would be 5 feet or less in either side-to-
side direction, the City will allow a 90 degree bend to be placed on the existing hydrant service line
and the hydrant to be relocated.
Section 8 Fire Hydrants
8-4
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9-1
Section 9
Line Valves, Air Relief Valves and Blow-off Chambers
9.1 Line Valves Appropriate line valves shall be properly located within the distribution mains. Such valves include
gate valves, butterfly valves, air control/vacuum breaker valves, and check valves. Valves 24 inches in
diameter and larger shall be installed in a dedicated water tight manhole or vault. The following
guidelines will assist the Design Engineer in the placement of isolation valves.
Valves shall be provided at locations that will not unduly impact the customer or reduce fire
protection and be easy to locate.
A minimum of two valves shall be provided at tee fittings, except fire hydrant tees, which
require a valve on the hydrant branch only. Additional valves may be required and shall be
approved by the City.
A minimum of three valves shall be provided at cross fittings.
Valves shall not be installed at street gutters, roadside ditch slopes or ditch flow lines.
Valves shall be located on all hydrant leads from the water main.
Valves shall be located upstream and adjacent to all existing and proposed fire hydrants.
The number of dead end lines shall be minimized by looping mains. All dead end mains shall
include a fire hydrant, located 10 feet away from the dead end.
The maximum line valve spacing on distribution mains is given in Table 9-1
Table 9-1 Line Valve Spacing
Land Use Maximum Valve Spacing in Fee
Residential Areas 800 feet
Business, Commercial and Industrial Areas 500 feet
In case of sparsely populated residential or commercial areas, valve spacing shall not exceed one mile.
9.1.1 Isolation Valves The following three (3) types of isolation valves shall be considered for water mains:
Vertical Gate Valve
Horizontal Gate Valve
Butterfly Valve
While most valves can be direct buried, there may be instances when it may be preferable to
install valves inside valve vaults. The Design Engineer shall design valve vaults for such
Section 9 Line Valves, Air Relief Valves and Blow-off Chambers
9-2
instances, taking into consideration the workspace requirements of the City’s field operations
team for maintenance, dis-assembly, etc. The valve vault lids shall be removable.
9.1.2 Pressure Reducing Valves High incoming water pressure from water mains shall be reduced with pressure reducing valves
(PRV) when transitioning to lower pressure zones. When the maximum static pressures in a new
system exceeds 100 psi, pressure reducing devices shall be provided. Use only Lead free PRVs. PRVs
can be installed in series or parallel configuration. For residential and commercial purposes, PRVs
shall be installed downstream of water meters. The following parameters shall be used for the
selection of PRVs:
To avoid cavitation, the maximum differential pressure across the PRV should not exceed 50
percent.
The maximum velocity through the PRV should not exceed 15 fps, and the minimum velocity
shall not be less than 1.5 fps. These velocities are based on full pipe size. The design velocities
for regulation should range from 6 to 15 fps.
9.2 Air Valves A pressurized pipeline is never without air, and in certain cases the air volume can be substantial. The
sources of air in a pressurized pipeline are initial startup of pipelines when the pipe line is empty,
presence of dispersed air in water, and through operations of certain mechanical equipment, example
air entrainment on the pump suction lines. It is also crucial that air be permitted into the lines during
dewatering operations to prevent a line collapse due to formation of a vacuum. Air valves can both
release and permit air into the line thereby ensuring smooth pumping operations and preventing
water hammers or a line collapse. In general, combination air valves are preferred for water mains.
However, other valve types listed in Section 9.2.2 may be suitable in certain instances. The Design
Engineer shall select the appropriate valve after evaluating the hydraulics of the watermain. The
Design Engineer shall provide the City all relevant justification when valves other than combination
air valves are used.
9.2.1 Requirements Air release valves/(combination) air valves are required at high points, or significant changes in
grade, and about every 2500 feet horizontal runs.
9.2.2 Types Three basic types of air valves in accordance with AWWA C512:
Air Release Valves: Designed to collect and release air that accumulates in the valve. An air
release valve can be used to vent air that is accumulated at high points of a pipe line when the
piping is under pressure.
Air/Vacuum Valves: Designed to allow air to escape while the pipeline is being filled or admit
air when the pipeline is being drained. When the internal pressure drops below atmospheric,
the valve opens, allowing in air to prevent the pipe from collapsing. However, after the line has
been filled, the pressure in the valve keeps the valve from opening even if air accumulates in the
valve. An Air/Vacuum valve can be installed downstream of pumps and at high points to
exhaust large volumes of air during pump startup and pipeline filling.
Section 9 Line Valves, Air Relief Valves and Blow-off Chambers
9-3
Combination Air Valves: This valve is a combination of air release valve and vacuum relief valve,
and is capable of releasing small amounts of accumulated air from the pipeline while under
pressure. Usually smaller valves include the required mechanism in a single body, on larger size
a dual body style installation is common. While single body valves are relatively cheaper, dual
body installations provide operational advantages due to the possibility of keeping the
Air/Vaccum valve in operation while the air release valve is under repair or maintenance.
9.2.3 Location and Sizing The appropriate valve type shall be determined by the Design Engineer in accordance with AWWA
Manual M51. Generally, the water line shall be designed and constructed to minimize localized high
points. Automatic air valves shall not be used in situations where flooding of the manhole or chamber
may occur.
9.3 Blow-off Chambers Chambers containing blow-offs or flush valves, and other appurtenances shall allow adequate room
for maintenance. The access opening must be suitable for removing valves and appurtenances. The
chamber shall be drained to atmosphere where it will not be subjected to flooding, or to an absorption
pit located above the seasonal groundwater table. Adequate venting shall be provided.
9.3.1 Requirements Blow-offs or flush valves shall be used where sediment blow-off is required. The blow-off chamber
shall be of materials and construction similar to manholes, except the top shall be a precast eccentric
dome section. Chambers containing blow-offs or other distribution system appurtenances shall not be
connected directly to any storm drain or sanitary sewer, nor shall blow-offs be connected directly to
any sewers.
9.3.2 Locations Blow-offs shall be located in City right-of-ways and close to drainage ditches. Blow-offs shall be
located at all low points of the transmission pipeline.
9.3.3 Sizing The minimum size of blow-offs shall be 4-inches. Blow-offs for other sizes shall be as stated below:
Size of Water Main Size of Blow-off
16-inch and below 4-inch
18 to 42-inch 6-inch
48-inch and above 8-inch
Section 9 Line Valves, Air Relief Valves and Blow-off Chambers
9-4
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10-1
Section 10
Water Meters
10.1 General Requirements All water service connections shall be metered. The Design Engineer is responsible for location,
selection, and sizing of water meters in accordance with the criteria listed herein.
10.2 Definitions 10.2.1 Residential Meter Residential meters are generally used in conjunction with a domestic water service of single-family
homes. These meters typically range from ⅝-inch through 2-inch in size.
10.2.2 Non-Residential Meter Non-residential meters are generally used to serve commercial or industrial water demand. These
meters typically range from 1-inch to 10- inches in size as required by the customer’s water demand,
while meeting all applicable plumbing code.
10.2.3 Irrigation Meter An irrigation meter is commonly used in conjunction with an irrigation water service to measure the
water flowing to a property that primarily services the needs of a landscape. All irrigation meters
must have a backflow prevention device.
10.2.4 Master Meter A master meter is typically used to serve a cluster of residential or commercial developments on a
single lot.
10.2.5 Sub-Meter These are privately owned meters that can be used to encourage effective conservation and efficient
use of water by fairly allocating its cost among the ultimate users within a master metered apartment
unit, office building, or shopping center. The sub-meters are not read and billed by the City as they are
considered private meters.
10.2.6 Deduct Meter (Private Meter) A deduct meter is usually installed on a specific water process, inside of private property. Deduct
meters subtract the process flow from the metered water flow.
10.2.7 Temporary Meters (Fire Hydrant Meter) Temporary water meters are typically used by contractors when drawing water for construction from
fire hydrants. These meters are typically 3-inches in diameter with a 2.5-inch hose and require
backflow prevention devices.
Section 10 Water Meters
10-2
10.2.8 Wholesale Meter (Customer City Meter) A wholesale meter is generally used to serve a wholesale municipal customer who purchases water
for resale.
10.3 Design Data Water meters shall be designed based on the peak water demand and type of application as necessary.
All meters shall be adequately sized in order to avoid the following undesirable conditions:
Volume, pressure and maintenance problems due to under sizing
Unregistered water use in low flow conditions due to over sizing
Accordingly, all applicable water usage including domestic, irrigation, mechanical, and fire demand
shall be considered while sizing a water meter.
10.3.1 Domestic Water Demand In the absence of an actual demand profile, the following modified fixture count method can be used to
estimate peak flow demand while meeting all applicable plumbing and fire codes.
10.3.1.1 Combined Fixture Value
Recommended fixture value as shown in Table 10-1 can be used to estimate combined fixture value as
necessary.
Table 10-1 Recommended Fixture Value
Fixture Fixture value @ 60 psi
Bathtub 8
Bedpan Washers 10
Bidet 2
Dental Unit 2
Drinking Fountain(public) 2
Faucet (kitchen sink) 2.2
Faucet (lavatory) 1.5
Faucet (utility sink) 4
Shower Head (shower only) 2.5
Toilet Flush Valve 35
Toilet Tank Type 4
Urinal (flush valve) 35
Urinal (wall or stall) 16
Urinal Trough (2 ft. unit) 2
Dishwasher 2
Clothes Washer 6
Hose (50 ft. length wash down)
1/2" connection
5/8" connection
3/4" connection
5
9
12
Source: AWWA M22: Sizing Water Service Lines and Meters, Second Edition
Section 10 Water Meters
10-3
10.3.1.2 Peak Domestic Demand
Figure 10-1 and Figure 10-2 can be used to determine low and high range of peak demands using
estimated combined fixture value:
Figure 10-1 Water Flow Demand per Fixture Value – Low Range Source: AWWA M22: Sizing Water Service Lines and Meters, Second Edition
Figure 10-2 Water Flow Demand per Fixture Value – High Range Source: AWWA M22: Sizing Water Service Lines and Meters, Second Edition
Section 10 Water Meters
10-4
10.3.1.3 Pressure Adjustment
Estimated peak demand shall be adjusted based on the actual available pressure at proposed meter
location (Table 10-2). Typically a fire hydrant test is requested to determine or verify the actual water
pressure at the peak demand of the proposed meter location.
Table 10-2 Pressure Adjustment Factors
Working Pressure a Meter
Discharge (psi)
Pressure Adjustment
factor
35 0.74
40 0.80
50 0.90
60 1.00
70 1.09
80 1.17
90 1.25
100 1.34
Source: AWWA M22: Sizing Water Service Lines and Meters, Second Edition
Example: The total fixture count of a facility at assumed 60 psi is calculated to be 100. The modified
fixture count at actual 80 psi will be 100*1.17= 117.
10.3.2 Irrigation Water Demand Irrigation water demand shall be estimated considering the following items:
Area to be irrigated.
Type of irrigation system to be used (spray or rotary).
Number of hose bibs and Pressure adjustment.
10.3.3 Mechanical Demand Mechanical water demand shall typically be obtained from Mechanical Electrical and Plumbing (MEP)
engineers considering the following items:
Type of equipment to be used (cooling towers, AC or wash down systems).
Type of usage (continuous or intermittent).
10.3.4 Fire Demand Fire demand shall meet the requirements of International Building Code (IBC), International Fire Code
(IFC) and National Fire Protection Agency (NFPA) and other regulations as applicable. Most recent
version of these regulations shall be used when determining fire demand. Fire demand shall typically
be obtained from Mechanical, Electrical and Plumbing Services (MEP), Fire Marshal’s office or the ISO,
and shall consider the following items:
Type of Building or Construction (Type 1A, 1B, IIA, IIB, IV, IIIA, IIIB, VA, VB).
Type of Occupancy (Residential or Non-Residential).
Type of Sprinkler System (Wet Pipe, Dry Pipe, Pre-Action and Deluge System), if any
Section 10 Water Meters
10-5
Types of Fire Pump (if any).
10.4 Meter Classification 10.4.1 Positive Displacement (PD) Meter Positive displacement meters shall typically be used for low flow rates (<160 gpm) with a wide range
of flow fluctuations.
10.4.2 Non-Displacement Meter If large capacity is of primary importance, and the flows are usually above 10 or 15 percent of the
maximum rating and low flow accuracy is secondary, a Non-Displacement meter can be considered.
10.4.3 Compound Meter Compound meters consist of integrally connected positive displacement and non-displacement meters
and are used to measure both low and high flows. Low flows are measured through positive
displacement, while high flows are measured by the non-displacement meter. If close accuracy at low
flows is important but large capacity is also needed, a compound meter can used.
10.4.4 General Use Recommendations General recommended uses of various types of meters are summarized in the Table 10-3.
Table 10-3 Recommended Use of Various Water Meters General Category
General Category Sub-Category Typical Use
Positive Displacement (PD)
(Low Flow Application)
Nutating Disc Oscillating Piston
- Single Family Residential - Apartment Building with Less than 100 Units - Small Businesses - Schools and Other Public Buildings without Large Irrigation
Non- Displacement
(High Flow Application where
Accuracy is secondary)
Velocity Turbine Multijet Magnetic (Mag) Ultrasonic Propeller Proportional
- Large Hotels - Factories - Public Irrigation - Large Office Buildings - Pump Discharge - Hospitals
Differential Pressure Fixed Opening: Variable Differential Orifice Venturi Variable Opening: Fixed Differential Rotameter
- Pump Discharge - Wholesale Water Purchasers - Research Applications - Subsystem Metering
Mass Flow
Level Measurement
Weir
Parshall Flume
Compound Standard Compound Fire Service - Schools with Irrigation - Laundries - Large Apartment Buildings - Fire Lines & Hospitals
Source: AWWA M22: Sizing Water Service Lines and Meters, Second Edition
Section 10 Water Meters
10-6
10.5 Meter Service Based on the estimated flow rate and type of service, the Design Engineer shall determine the need for
single or multiple services while considering the following criteria:
10.5.1 Domestic Service Meters A domestic service single meter shall be used primarily to measure domestic flows. Typical sizes of
small domestic meters are 5/8” , ¾”, 1”, 1-1/2” and 2”. A Domestic meter can also be used to
measure irrigation supplies and/or residential fire demand with approved fire sprinkler systems.
Domestic service meters are usually Nutating disc PD meters.
10.5.2 Large Domestic Service Meters Typical sizes of large domestic meters are 3”, 4”, 6”, 8” and 10”. These meters can be Nutating disc PD,
turbine or compound meters.
10.5.3 Fire Service Detector Check Device Detector Checks (DC) are typically installed on closed fire lines to measure fire flow to approved
automatic fire sprinklers. Minimum size of DC shall be 4”. Where necessary 6”, 8” and 10” DCs can be
used. Usually a 5/8”- 1” Nutating Disc PD meter is also installed in the bypass line. The bypass line
installed on a dedicated fire line shall not be used for domestic consumption.
10.5.4 Irrigation Service Meter Irrigation service meters are used to measure water used for irrigation or landscaping. Typical single
irrigation meter sizes are 1”, 1 ½”, 2”, 3”, 4” and 6”. All irrigation service lines shall also include a
backflow prevention device.
10.5.5 Combined Water and Fire Services Meters A single or combination of meter(s) can be used to measure combined water, fire and/or irrigation
flows as required.
10.5.5.1 Small Combined Water and Fire Service Meter(s)
Typical size of meter to measure small combined water, and internal fire sprinkler flow is 1”-2”. A
Multijet turbine meter shall be used to measure residential/domestic service with fire demand.
10.5.5.2 Large Combined Water and Fire Service Meter(s)
Typical size of fire meters used on combined service shall be 4” (min.), 6”, 8” and 10”. Typical size of
domestic meter on combined service is 1”, 1-1/2”, 2”, 3”, 4”, and 6”.
10.6 Location and Installation Water meters shall typically be located at the property line (preferably at the center of the sidewalk)
in the public right-of-way or in a servitude dedicated to the City.
10.6.1 Accessibility All meters must be placed in a location where they can be read and accessed by the City’s meter
reading personnel. The meter must be accessible at all times and the surrounding area must be kept
clear of vegetation and other obstructions.
Section 10 Water Meters
10-7
10.6.2 Minimum Length of Unobstructed Pipe The meter shall be located in a straight, clean pipe of uniform, circular cross section, without any
fittings or obstructions. A minimum length of ten (10) diameters of straight, rigid pipe must be fitted
on the intake side of the meter, and a minimum of five (5) diameters of straight rigid pipe on the
discharge of the meter to minimize flow disturbance. Where this requirement cannot be met, it may be
acceptable (upon approval from the City) for the meter to be installed with a minimum of five (5)
diameters of straight, rigid pipe upstream of the meter, and a minimum of two (2) diameters of
straight, rigid pipe immediately downstream. However, this will only be considered in those
circumstances where the meter manufacturer warrants that the meter will operate to the required
accuracy under the revised conditions. Minimum length of straight, uninterrupted pipe is summarized
in Table 10-4.
Table 10-4 Required Minimum Straight Unobstructed Pipe Length for Water Meter
Meter Size (in)
Min. Straight Unobstructed Length
Intake or Up Stream (U/S) Side (ft.) Discharge or Down Stream(D/S) Side (ft.)
5/8 0.52 0.26
¾ 0.63 0.31
1 0.083 0.42
1-1/2 1.25 0.63
2 1.67 0.83
3 2.5 1.25
4 3.33 1.67
6 5 2.5
8 6.67 3.33
10 8.33 4.17
12 10 5
>12 As Calculated As Calculated
10.6.3 Miscellaneous Items The meter shall be installed so that there is a full pipe of water on both the intake and discharge sides
of the meter at all flow rates. The meter shall not be installed in a section of pipe with potential for air
pockets or that does not run full of water. If it is likely that air will become entrapped near the meter,
an air valve shall be installed. Filtering equipment shall be installed on the intake side of the meter.
Where the meter has to be fitted to plastic or polyethylene pipelines, it must be supported by a
concrete thrust block or fabricated steel bracing to maintain stability.
10.7 Meter Box and Vault 10.7.1 General No meter shall be installed deeper than 4.5 feet below ground level. Where a meter is installed
underground, sufficient space must be provided to facilitate easy access for maintenance and reading
at all times.
Section 10 Water Meters
10-8
10.7.2 Meter Box All 2” or smaller meters located down to 1.5’ below ground will require a suitable meter box to house
the meter. All meter boxes are to be constructed of plastic with cast iron or Advance Metering
Infrastructure (AMI)-compatible Radio Frequency (RF) lids as approved by the City.
10.7.3 Meter Vault All 3” or larger domestic, fire, irrigation or combined meters will require a meter vault. For meters
located between 1.5 feet and 4.5 feet below ground, an access pit or meter vault will be required.
10.8 Special Design Considerations 10.8.1 Deduct Meter 10.8.1.1 General
Deduct meters can be considered for facilities where the water either evaporates or is consumed in a
specific process including, but not limited to, cooling towers, bottling plants or similar applications as
approved by the City.
10.8.1.2 Typical Configurations
The following are the most common configurations currently approved for use by the City. Other
configurations may be submitted,for review on an individual basis.
Wastewater Meter: Wastewater meter to measure total discharge into the wastewater
collection system. If the customer has more than one wastewater lateral, a meter will be
required for each lateral.
Deduct Water Meter: Deduct water meter(s) can be used to measure water which does not
return to the wastewater collection system. Volume measured on the deduct meter is
subtracted from the total water volume for the calculation of wastewater charges. Deduct
meters are typically located at both the supply side, and the return side of the process as
approved by the City. An example would include water to be consumed in a manufacturing
process.
10.8.2 Wholesale Meter 10.8.2.1 General
Wholesale customer meters are coordinated through the City. Wholesale customer meters are
typically designed and constructed by the party requesting the service from the City. The City reads
and maintains wholesale meters.
10.8.2.2 Typical Configurations
A wholesale customer meter assembly typically consists of a primary and a secondary flow meter. The
Primary flow meter shall be sized based on the estimated flow to the customer. Venturi tubes or
similar meters, as approved by the City, shall be used as primary flow meter. The Design Engineer
shall also size a secondary flow meter to measure any flows through the bypass line.
11-1
Section 11
Cross Connection Protection
A cross connection is a direct or indirect connection of a non-potable water line with a potable water
supply line. Cross connections can significantly deteriorate the quality of potable water, and could
render it a health hazard. The degree of hazard posed by cross connections depends upon the type of
potential contaminant and the likelihood for backflow to occur.
HIGH HAZARD is a cross connection involving any substance that if introduced into the public water
supply could cause death, illness, spread disease or has a high probability of causing such effects.
LOW HAZARD is a cross connection involving any pollutant that is not generally a health hazard, but
would pose a hazard if introduced into the potable water supply, constitute a nuisance or be
aesthetically objectionable.
11.1 Required Pipeline Separation The required pipeline separation shall be as given in Section 7.7.
11.2 Backflow Prevention Devices Backflow is an undesirable reversal of flow of liquid from a non-potable system to the potable water
distribution main piping system. The causes of backflow are backpressure, back-siphonage, or a
combination of the two. The backflow devices used to prevent backflow from a potential cross
connection include:
Air gaps
Atmospheric vacuum breakers
Pressure vacuum breakers
Double check valve assemblies
Reduced pressure zone backflow prevention assemblies
Barometric loop
In all cases, the Design Engineer shall be responsible for selecting the appropriate backflow
prevention devices for a specific location. In parallel installations, backflow devices should be the
same type (provide the same level of protection), and should have the same size and flow capacity.
11.3 Backflow Prevention for Commercial, Industrial, and Multi Family Residences All commercial, industrial, and multi-family residential projects shall install a reduced pressure
principle backflow preventer assembly or a double check valve assembly. The device shall be installed
above ground in an enclosure (below ground installation in valve vaults will not be permitted), the
Section 11 Cross Connection Protection
11-2
piping and device shall be insulated to provide freeze protection. Design Engineer shall add the
backflow prevention device(s’) size information and coordinates. Projects with fire sprinklers and
standpipe systems, and projects with on-site fire protection systems will be required to install a
reduced pressure type backflow preventer with a leak detector assembly.
11.4 Backflow Prevention for Irrigation System A reduced pressure principle backflow preventer shall be required on all irrigation systems that have
chemical substances or additives. In cases where an irrigation system does not have chemical
substances or additives, a double check valve backflow (DCVA) prevention assembly shall be required.
11.5 Locations for Backflow Prevention Devices 11.5.1 Locations Cross connection can occur at several locations within commercial buildings, hospitals, farms, houses
and apartment complexes. Backflow prevention devices are required at all cross connections. Follow
plumbing code requirements for toilets, urinals, hose connections, air conditioning units, heat
exchangers and other water cooled equipment. The ensuing subsections present examples of locations
for backflow prevention devices.
11.5.1.1 Fire Sprinkler Systems
Fire sprinkler systems can be a source of potable water contamination. During a fire emergency, non-
potable water can be drawn into the City’s potable water system because of the pressure and volume
demands. Fire sprinkler systems with no chemicals added shall be isolated from the potable water
supply by double check valve assemblies. Fire sprinkler systems which contain additives or are cross
connected with other piping systems shall be isolated from the potable water supply by reduced
pressure zone backflow prevention assemblies.
11.5.1.2 Irrigation / Lawn Sprinkler Systems
Irrigation systems are a high hazard since in nearly all instances chemicals are applied. Backflow
preventer such as reduced pressure zone backflow prevention assemblies or approved vacuum
breaker shall be located on all sprinkler systems.
11.5.1.3 Auxiliary Sources
There shall be no connection between the distribution system and any pipe, pumps, hydrants, or tanks
whereby unsafe water or other contaminats may be discharged or drawn into the public potable water
system.
11.5.1.4 Wastewater Treatment Plants, Pump Stations and Water Reduction Facilities
Common cross connections in plants of this type are usually found between the potable water system
and:
Water operated sewage sump ejectors; high hazard.
Chlorinators using potable water when disinfecting wastewater; high hazard.
Sewer lines for purpose of disposing of filter or softener backwash water or water from cooling
systems; high hazard.
Reduced Pressure Backflow Prevention Devices should be used in these locations.
Section 11 Cross Connection Protection
11-3
11.5.1.5 Water Treatment Plants
Common cross connection hazards in plants of this kind are found between the potable water system
and:
Raw water pumps for priming, cleaning, flushing or unclogging purposes.
Any chemical feed applications using potable water system.
Filter backwash systems.
Chemical Feed Day Tank Fill Stations.
Reduced Pressure Backflow Prevention Devices should be used in these locations.
11.5.1.6 Plating and Chemical Companies
The cross connection hazards found in plants of this type include cross connections between the
public water supply and:
Plating facilities involving the use of highly toxic cyanides, heavy metals in solution, acids and
caustic solutions.
Plating solution filtering equipment with pumps and circulating lines.
Tanks, vats or other vessels used in painting, descaling, anodizing, cleaning, stripping, oxidizing,
etc. for the preparation or finishing of products.
Steam generating facilities and lines which may be contaminated with boiler additive chemicals.
Water cooled equipment which may be connected to a sewer such as compressors, heat
exchangers, and air conditioning equipment.
Reduced Pressure Backflow Prevention Devices should be used in these locations.
11.5.1.7 Other Locations
Other similar areas include hospitals, convalescent and nursing homes, funeral homes and mortuaries,
schools and universities, medical laboratories, car wash facilities, laundries, potable water tanks,
swimming pools, green houses, and tank trucks and sprayers. In circumstances where the Design
Engineer encounters these areas, the Design Engineer shall determine specific locations for backflow
prevention devices.
11.6 Plumbing Code In all circumstances, the installation of backflow prevention devices shall conform Chapter 22 –
Buildings and Building Regulations of the City of Shreveport Code of Ordinances, requirements of the
City’s Permitting Office standards, and Louisiana State Plumbing Code (Part XIV (Plumbing) of the
State Sanitary Code).
Section 11 Cross Connection Protection
11-4
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12-1
Section 12
Pipe Aerial Crossings
12.1 General Considerations With the approval of the City, the Design Engineer shall either use piers or supports/carriage for pipe
aerial crossings. If permitted, an existing bridge structures may be used to cross streams and ditches.
Before designing the crossing, the Design Engineer shall contact the owner of the bridge structure and
obtain written approval to determine if its use is permissible.
The design elevation of the proposed aerial crossing line shall be maximum of:
The elevation of the lowest chord of the nearest adjacent bridge or
Shall be above the 100-year Floodplain Elevation
12.2 Design Considerations The Design engineer shall incorporate the following design considerations:
Pipes used for aerial crossings that span the length of elevated pier crossings shall be flanged
ductile iron pipe, Pressure Class 350 conforming to AWWA C115, C150 & C151.
All pipes over piers spaced greater than normal pipe lengths of 18 feet or 20 feet shall be
multiple length pipes with flanged joints and gaskets suitable to convey the fluid at ambient
conditions.
The pipes shall be designed per AWWA C150 to limit stresses.
Pipe deflection (at center of span) when flowing full shall not exceed 0.15 percent of the pipe
length.
Expansion joints and pipe rollers shall be provided as required.
Adequate provisions must be made for thrust restraints at points of transition from a buried
pipe to an exposed pipe and vice versa.
Wastewater mains shall be fully restrained across the aerial section.
The impact of increased load due to the proposed crossing shall be calculated before finalizing
the aerial crossing option.
Adequate access shall be provided to both ends of the crossing.
The provisions for corrosion control shall be incorporated, including coating systems.
Freeze potential shall be considered for low flow aerial crossings.
Section 12 Pipe Aerial Crossings
12-2
Install isolation valves or other flow regulating devices as required. The flow regulating devices
shall be located on each bank or at a safe distance from each bank. There shall be no discharge
into the stream or the water body.
Install supports for all joints in pipes utilized for aerial crossings to prevent overturning and
differential settlement. Expansion joints or couplings shall be used, as required, at locations
where the aerial pipe connects to buried piping.
Air relief provisions (with freeze protection) shall be considered at the high points.
Supports, piers or abutments shall be designed to withstand the hydrodynamic effect of the
stream flow pressure on the pipes and its supports.
All exposed pipes shall be epoxy coated (externally).
All flanges, nuts, bolts shall conform to AWWA standards.
The nuts and bolts shall be stainless steel or as directed by the City.
The Design Engineer shall submit detailed calculations for loading bearing, anchor design, and other
engineering calculations to the City for review.
13-1
Section 13
Pipe Stream Crossings
13.1 Design Considerations The Design Engineer shall consider the following in selecting stream crossing locations:
Avoid locations with severe channel instability problems.
In locations with meandering channel bends, the crossing should be placed halfway between
the two adjacent bends or upstream of the meandering bend.
Avoid locations where there is an abrupt drop in the channel bed, flow depth or localized scour
holes. These locations indicate potential channel bed instability.
In locations where flow constrictions occur, the crossing should be placed upstream of flow
constriction.
Avoid placement near sediment traps and storm water control ponds. The crossing should be
located downstream of these structures.
Stream crossing shall be located such that the pipe will be protected from impacts of
construction of other utilities or structures.
As far as possible, inverted siphons are to be avoided. Gravity sewers shall be sloped to
maintain self-cleaning velocities.
Provide a minimum cover of five (5’) feet over the pipe at stream crossings.
For crossings over 15-feet (measured at low flow conditions), the following shall be
implemented:
- Isolation valves shall be provided at both ends, within half a mile for mains less than 24
inches, and within 2.5 miles for mains 24 inches and larger. The valves shall be easily
accessible and not subject to flooding under normal conditions.
- All other mains, services, taps, hydrants, or other devices located inside of the limits of the
isolation valves shall also have easily accessible isolation valves.
- Permanent taps shall be provided to install a meter check for leakages and for sample
collection. It is permissible to have combination taps for both an air relief valve and a
pressure tap provided the assembly meets the above criteria and the air relief valve can be
isolated during the testing of the crossing.
The pipeline shall be checked for the potential for buoyancy lifts, and designed with
antifloatation devices.
Section 13 Pipe Stream Crossings
13-2
13.2 Material and Appurtenances The stream crossing shall be installed in a casing pipe under the ditch or stream. The
water/wastewater main shall be restrained ductile iron pipe. If a trenchless technology is used for
stream crossing, the Design Engineer shall select the appropriate pipe material. There shall be an
access manhole on each bank of the ditch or stream. The height of manhole shall be 3-feet above the
100 yr. flood elevation.
13.3 Erosion Control The Design Engineer shall incorporate erosion control in the design. The Design Engineer shall follow
the requirements of the regulatory agency or the Owner responsible for the ditch or stream. The
design shall follow all permit requirements of the regulatory agencies. The stream crossing shall be
covered with riprap if the velocity of the flowing water is anticipated to exceed ten (10) feet per
second. In areas where there is a planned channel improvement, coordinate with the Designer of the
channel improvement to determine any additional improvements that may be required. In addition,
the Design Engineer shall design the stream crossing to have a minimum depth of five (5) feet from
the top of the pipe to the bottom of the channel or as stipulated by regulatory agency in case of
navigable waters.
Appendix A-1
Appendix A
Consulting Rating Form
CITY OF SHREVEPORT
DEPT. OF ENGINEERING AND ENVIRONMENTAL SERVICES OFFICE OF THE CITY ENGINEER CONSULTANT RATING FORM
Project Name/No: Consultant:
Type of Construction: Coordinator:
Explanation: To evaluate the Consultant, circle the number which best rates their performance from the range for each of the five criteria. Rating will be
from worst to best on a 0.0 to 6.0 scale, and will be in accordance with the detailed attached rating factors.
1. Demonstration of knowledge of acceptable Design Criteria and procedures. Considerations include but not limited to demonstrated familiarity with Design Manuals, AASHTO specifications, good design practices and design standards.
0 1 2 3 4 5 6
Remarks:
2. Ability to meet contract requirements with minimum direction. Considerations include whether or not the Consultant was a self starter and whether or not the Coordinator spent considerable time instructing the consultant and/or correcting his work.
0 1 2 3 4 5 6 Remarks:
Appendix A Consulting Rating Form
Appendix A-2
CONSULTANT RATING FORM 3. Quality of plans. Consideration on the legibility, neatness, organization, format,
accuracy of quantities, details and correctness of plans. Quality of plans primarily based on reviews made at an advanced stage of preliminary and final design.
0 1 2 3 4 5 6 7
Remarks:
4. Completion of work within the terms of contract. Considerations include whether or not the Consultant completed the plans on or before the contract completion date; and whether or not intermediate deadlines were met. Any delays due to the City's inability to provide data or reviews in a timely manner should be considered in this rating and comments provided.
0 1 2 3 4 5 6
Remarks:
5. General spirit of cooperation. Excellent - very cooperative, very willing to follow instructions, interested in project. Unsatisfactory - argumentative, reluctant to follow instructions, indifferent to projects.
0 1 2 3 4 Remarks:
Appendix A Consulting Rating Form
Appendix A-3
CONSULTANT RATING FORM
General Comments:
Rater’s Signature: Date:
Cons ultant’s Comments :
Consultant’s Signature: Date:
City Enginee r’s Comme nts :
City Engineer’s Signature: Date:
Dire c tor of Opera tional S ervic e s ’ Comments:
Director of Operational Services’ Signature: Date:
Appendix A Consulting Rating Form
Appendix A-4
CONSULTANT RATING FACTORS
1. DEMONSTRATION OF KNOWLEDGE & DESIGN CRITERIA
6 No design errors on plans 5 Minor design error 4 Few minor design errors 3 One major and/or several minor errors 2 More than one major error 1 Lack of knowledge. Large number of questions 0 Totally unacceptable
2. ABILITY TO MEET CONTRACT REQUIREMENTS W/MINIMAL DIRECTION
6 No questions w/no errors 5 Few intelligent questions w/few errors 4 Few questions 3 Few less than intelligent questions 2 No questions w/numerous errors, numerous dumb questions, needs some
prodding to look at options. 1 Continuous questions on major & minor issues 0 No understanding
3. QUALITY OF PLANS
7 No errors 6 Few minor errors/neat plans 5 Some minor errors/neat plans 4 Some minor errors/plans are not neat. A major error/neat plans 3 Numerous minor errors/average plans 2 Major errors/lacking quantities 1 Numerous errors/fairly neat plans. Few errors/unorganized or minimal plans 0 Totally unacceptable
4. COMPLETION OF WORK WITHIN TERMS OF CONTRACT
6 All submittal early 5 All submittal early or on time 4 All submittal on time; some early, some slightly late 3 Slightly behind schedule with some submittal on time 2 Always slightly behind schedule 1 Late letters frequently sent 0 Non compliance
Appendix A Consulting Rating Form
Appendix A-5
5. SPIRIT OF COOPERATION
4 Extremely/always cooperative 3 Mostly cooperative 2 Sometimes cooperative & sometimes questionable 1 Usually uncooperative or argumentative 0 Uncooperative/argumentative
Section 1 Introduction
Appendix A-6
This Page Intentionally Left Blank
Appendix B-1
Appendix B
Plan Review Checklist
PLAN REVIEW CHECKLIST
PURPOSE:
The purpose of this checklist is to expedite plan review of street, storm drainage, water, and sewer plans
requiring approval by the City Engineer, as well as help standardize plans for the City of Shreveport.
This checklist is intended to help reviewers and the consultants standardize plans and minimize the
probability of misinterpretation by field personnel during construction layout engineering and
inspection.
This checklist is intended to be a guide and reference for the submittal and review of design plans. The
items listed on the checklist are not to be intended as all-inclusive for every project. Depending on the
scope of the project, sheet requirements may or may not include all of the sheets as listed below, or may
include additional sheets not listed in this checklist.
INSTRUCTIONS:
1. The checklist is separated into the following sections to correspond to the general requirements of
the plan submittal.
A. Overall Drawing Requirements
B. General Sheets
C. Layout Sheets
D. Right-of-Way Sheet
E. Plan and Profile Sheet(s)
F. Standard and Special Detail Sheet(s)
G. Erosion Control Layout Sheet
2. Fill in the Project Name, City of Shreveport Project Number (if known), and submittal date, on the
first page of the checklist.
3. Complete each section of the checklist by checking each appropriate item as shown on the submitted
plans.
4. Where items or sections do not apply, insert a “N/A” (non-applicable) in the allotted space provided.
5. Submit completed checklist with plan submittal package.
Appendix B Plan Review Checklist
Appendix B-2
PLAN REVIEW CHECKLIST
PROJECT NAME:
DATE:
PROJECT NUMBER:
DESIGNER:
OVERALL DRAWING REQUIREMENTS
1. ______ Plan Sheet Size is 22" x 34"
2. ______ Plans are drawn to a Horizontal Scale of 1"=20', and a vertical scale of 1"=4'. (Larger scales can
be used for increased clarity or conciseness of the plans with prior permission of the City
Engineer. Smaller scales can be used in the profile for sewer mains).
3. ______ Each Sheet shall contain a sheet number, the total number of sheets in the plans, and the proper
project number.
4. ______ A revision block will be included on each sheet. Revised sheets submitted shall have identifying
notations and dates for each revision.
5. ______ All lettering shall be ≥0.125"
6. ______ The design engineer information including name and address is shown on each plan sheet.
7. ______ The final plans and specifications shall be signed, dated and sealed by the responsible
engineer(s). Responsible engineer shall be a registered Professional Engineer, licensed to
practice in the State of Louisiana.
8. ______ The final set of plans shall be submitted on full size, 20 lb. weight archive-able paper.
Specifications shall be printed on 8 ½" X 11" paper. All final sets (plans and specifications) shall
be clipped and bound.
9. ______ Once approved, the final set of plans and specifications shall also be submitted electronically to
the city. All reference files will be bound into one overall drawing file. The naming format for
the drawing files shall be “Project Number, Page #, _, Total Page# (i.e. 01C0011_20, project
number is 01C001, the page # is 1, and the total page # is 20). Final plans shall be submitted
either in Microstation or AutoCad. Final plans (signed, dated and stamped) shall also be
submitted in ‘pdf’ format. Final specifications shall be submitted in both ‘Microsoft Word’ and
‘pdf’ formats.
Appendix B Plan Review Checklist
Appendix B-3
GENERAL SHEETS
General sheets shall include the Title Sheet, Index Sheet, General Notes, Legends and Abbreviation, Hydraulic
Profiles, and Pipe, Valve and Equipment Schedules. Project work involving upgrades to existing treatment
plants or new treatment plans shall include Process Flow Diagrams. Minimum requirements for each of these
sheets are listed below.
TITLE SHEET
The title sheet shall list the following information.
1. ______ All plans shall include this text at the top: “CITY OF SHREVEPORT, LOUISIANA. DEPARTMENT OF
ENGINEERING AND ENVIRONMENTAL SERVICES. OFFICE OF THE CITY ENGINEER.”
Immediately below this text, the name of the project or title, city, and parish shall be listed .
2. ______ Project number
3. ______ Location Map showing project location in relation to streets, railroads, and physical features.
The location map shall have a north arrow and appropriate scale. The location map shall show
the beginning and end stationing of the project.
4. ______ Vicinity Map showing project location in relation to City of Shreveport map. The vicinity map
shall have a north arrow and appropriate scale.
5. ______ For City of Shreveport projects, the Mayor, Director of Operational Services, or the Director of the
responsible department, and City of Shreveport City Council Members listed by district, shall be
shown on the title sheet.
6. ______ The name of the City’s Water and Sewer Director.
7. ______ Funding information for City of Shreveport projects.
8. ______ Approval block for signature by the City Engineer, and date.
9. ______ Approval block for signature by the Assistant City Engineer, and date.
INDEX SHEET
Index sheet(s) shall be included for all projects.
GENERAL NOTES
General notes shall include the following at a minimum:
1. ______ A note stating the following, in bold letters and framed in a box: “CONTRACTOR TO CALL LA.
ONE CALL OR THE UTILITY COMPANY”
2. ______ A note listing the agencies and their phone numbers in case of an emergency.
3. ______ A note stating that the Contractor shall be responsible for protection of existing utilities in the
area of work.
4. ______ A note stating that Health and Safety at the jobsite, during construction, shall be the Contractor’s
responsibility.
Appendix B Plan Review Checklist
Appendix B-4
5. ______ A note identifying the permits that the Contractor will need to obtain prior to beginning work.
6. ______ A note pertaining to relevant coordinates, datum used in surveys, and adjustment factors (if
used).
7. ______ A note stating the following: “REDLINE DRAWINGS SHALL BE PRESENTED TO THE CITY’S
REPRESENTATIVE PRIOR TO PAY REQUEST APPROVAL AND FINAL COMPLETION.”
8. ______ If required, a note stating that the City’s standard specifications will be used for the project.
9. ______ If required, a note regarding demolition activities, directing the Contractor to contact the City
regarding preferences in salvaging demolished items.
10. ______ If required, a note pertaining to disposal of demolished items in compliance with prevailing
regulations.
LEGENDS & ABBREVIATIONS
All legends and abbreviations used in the plans shall be listed in these sheet(s). For smaller jobs, it may be
possible to merge this with the General Notes sheet. For complex projects, separate sheets for legends and
abbreviations may be required for each discipline.
HYDRAULIC PROFILES
Hydraulic profiles may not be required for all projects; they are required for certain treatment plant projects,
pump station and piping projects. Where required, such profiles shall be constructed for each structure,
piping junction as required. It shall be developed for current, design, and future flows.
PIPE, VALVE & EQUIPMENT SCHEDULES
These schedules may only be required for certain projects. The Design Engineer shall list these schedules for
pipes, valves and/or equipment of certain sizes. When used, the Design Engineer shall list their sizes
(diameters, dimensions), type (pipe type, pipe class/schedule, valve type, valve opening, equipment operation
type, etc.), capacity (flowrate, throughput, etc.), and electrical sizes (HP, rpm etc.).
LAYOUT SHEETS
Layout sheets shall include Site Layout sheets, and Topographic Survey sheets. Requirements for these sheets
are stated below.
SITE LAYOUT SHEETS
1. ______ North arrow and scale
2. ______ Name of subdivision and all street names and an accurate tie to at least one quarter section
corner. Unplatted tracts should also have an accurate tie to at least one quarter section corner.
3. ______ Boundary line for project area.
4. ______ Location and description of major waterways or water bodies within or adjacent to the project
area.
Appendix B Plan Review Checklist
Appendix B-5
5. ______ Name of each utility within or adjacent to the project area and the telephone number of the
contact.
6. ______ If applicable to the project, Contractor staging area, and spoils area.
7. ______ If more than one general layout sheet is required, a match line should be used to show
continuation of coverage from one sheet to the next sheet.
TOPOGRAPHIC SURVEY
For most projects survey information can be included in the layout sheets. However, for projects involving
pipelines, relevant survey information shall be shown on all applicable plan and profile sheets.
1. ______ North arrow and scale.
2. ______ A legend is shown for all symbols and hatches used.
3. ______ Vertical Datum stated, and at least two benchmarks are shown and listed. The monument number, elevation, northing and easting, and location description shall be shown.
4. ______ Existing contours shown at each foot of elevation (unless other approved).
5. ______ Street names are shown along roadway centerline.
6. ______ Limits of right-of-way is shown on the plan.
7. ______ Call-outs for all objects and features on survey.
8. ______ Existing sewer and storm drainage structures are shown and listed and stationed with rim
elevation, pipe size, pipe material, and pipe invert elevation.
9. ______ Underground stormwater, sanitary sewer, and waterlines are shown and labeled with size and
material type.
10. ______ All utility structures such as electrical vaults, power poles, guy wires, gas meters, water meters,
water vaults, telephone poles, telephone vaults, are shown and called out with station and offset.
11. ______ All overhead and underground utility lines are shown and labeled.
12. ______ Utility servitudes are shown and labeled.
13. ______ Culverts are shown, and labeled with pipe material, pipe size, flow line elevation, and station and
offset at each end. Any extension of an existing culvert is shown and labeled.
14. ______ Landscape features such as trees, shrubs, and site amenities are shown and labeled with station
and offset.
15. ______ Property Lines are shown. Property including owner, address, lot number is shown.
16. ______ The survey information is shown for 300' beyond the project limit.
17. ______ All driveway locations are shown on the plan, stationed to the center of driveway. The width and
material type of driveway is listed.
Appendix B Plan Review Checklist
Appendix B-6
18. ______ The sidewalks are shown on the plan. The type of material is called out on the plan. Any ramps
are shown.
19. ______ The survey is signed and stamped by a licensed surveyor in the State of Louisiana.
RIGHT-OF-WAY SHEETS
These sheets may be issued by themselves or attached to Design Reports and Specifications. Right-Of-Way
sheets shall include the following information:
1. ______ Parcel number.
2. ______ Lot number.
3. ______ Subdivision.
4. ______ Name of current owner.
5. ______ Servitude takings (Should be labeled as P-# for Right-of-way, D-# for drainage, T-# for
temporary construction) with dimensions.
6. ______ Right-of-way takings.
7. ______ Geographical Number.
8. ______ Plat sheets are to be 8 ½"x11".
PLAN AND PROFILE SHEETS
Plan and Profile sheets shall include Site Civil sheets, Architectural sheets, Structural sheets, Process
Mechanical sheets, Mechanical sheets, Electrical sheets and Instrumentation and Control sheets. The
requirements for these sheets may vary depending on the project scope. Not all of these sheets are discussed
in detail in this section. Overall requirements for these sheets are listed below.
SITE CIVIL PLANS
1. ______ North arrow and scale (Horizontal scale of 1"=20').
2. ______ Elevation and location of all applicable bench marks.
3. ______ Show Right-of-Way boundaries and limits and associated dimensions.
4. ______ Detailed locations of proposed structures, process units, piping, vaults, and other items.
5. ______ Existing structures such as manholes, sanitary sewer manholes that need to be adjusted are
shown on the plan. Sanitary sewer manholes need to state the flow line elevations, sewer main
size, and rim elevation.
6. ______ Show all existing and proposed utilities such as power, gas, oil, water, telephone, existing storm
sewers and existing and proposed sanitary sewers showing direction of flow and other such
items located in conformance with the best information available or by field surveys, and
identified as to size, type of utility, and where known- the type of material.
7. ______ Show all utility servitudes. Dimension and label width and ownership of servitude(s).
Appendix B Plan Review Checklist
Appendix B-7
8. _____ All existing and known proposed improvements shall be identified as to type, size, material, etc.,
as may be applicable. Existing conditions need to be screened back (presented as a lighter line
color) on the drawing.
9. ______ Proposed work needs to be obviously darker on the drawings than the existing conditions.
10. ______ Show the flow line and top of bank of existing open channels and the centerline and top of bank
of proposed open channels.
11. ______ Show pipeline stationing along the centerline.
12. ______ Show complete centerline curve data for each curve along with points, bearings, curvature, and
tangency.
13. ______ Show all railway information if applicable; their ownership, right-of-way width, angle of
intersection and location.
14. ______ Show boring locations if available.
15. ______ Limits of clearing shall be shown on the plan. All encroachments or excess right- of-way is
clearly shown on the plan.
16. ______ Profile grade line identified on plan.
17. ______ The plans will show a 10' horizontal separation between the water and sewer lines.
18. ______ Include drainage plans for applicable concrete pad drawings.
19. ______ Callout pipe size, material and service type on plans (ex: 24-PVC-SFM for 24” PVC sewer force
main)
20. ______ Callout valve sizes, valve types and fittings (ex: 42-BFV for 42 inch Butterfly Valve)
21. ______ Identify the Control Points and Bench Marks. Callout Northings, and Eastings of all manholes,
pipe fittings, valves, corners of buildings, paving, roads, etc.
SITE CIVIL PROFILES
22. ______ The profile shall have a horizontal scale of 1"=20', and a vertical scale of 1"=4', unless approved
by the City Engineer.
23. ______ Existing and proposed grade elevations are shown.
24. ______ Depth and location of existing or proposed utilities and sanitary sewers where such information
is available, or in the case where the depth is not known, approximate elevations shall be used
and noted as approximate. Each facility shall be properly identified.
25. ______ Proposed sewers shall be shown as double solid lines properly showing the height of the pipe.
26. ______ Open channel profiles with the proposed flow line, gradient, and the depth of special protection
(if required).
27. ______ The clearing distance between utilities is shown.
28. ______ The cover over the water pipe is shown.
Appendix B Plan Review Checklist
Appendix B-8
ARCHITECTURAL SHEETS (If Applicable)
1. ______ Include a General Architectural Notes sheet.
2. ______ Include a Legends & Abbreviations sheet if required.
3. ______ Include Code Plans as applicable to the project.
4. ______ Include Floor Plans as required.
5. ______ Show Building Elevation and Section sheets depicting all applicable demolition, modification and
construction activities.
6. ______ Include Standard Architectural Details sheet as required.
STRUCTURAL SHEETS (If Applicable)
1. ______ Include a General Structural Notes sheet(s).
2. ______ Include a Legends & Abbreviations sheet if required.
3. ______ Include Overall Plans and Sections if required.
4. ______ Include structural sheets for all applicable installations/equipment/structures that include:
a. ______ Pertinent dimensions.
b. ______ Type of concrete to be used.
c. ______ Type of metal to be used.
d. ______ Rebar size, location, numbers, spacing and clearances.
5. ______ Include a Standard Structural Details sheet.
PROCESS MECHANICAL SHEETS (If Applicable)
1. ______ Include a General Process Mechanical Notes sheet(s).
2. ______ Include a Legends & Abbreviations sheet if required.
3. ______ Include an overall Process Mechanical plan if required. Plan shall include layout dimensions,
interior clearances, wall thicknesses
4. ______ Include Plans and Profiles of associated/affected Structures. In certain cases, more than one plan
or profile sheet may be required. All associated dimensions, and clearances shall be clearly called
out.
5. ______ Include Plans and Profiles of associated process equipment with dimensions, and clearances
clearly called out.
6. ______ Fittings, piping and valves shall be clearly marked. Pertinent fixtures, fittings, and supports shall
also be indicated.
Appendix B Plan Review Checklist
Appendix B-9
7. ______ Call out pipe sizes, pipe material, and type of service (ex: 4-SS-AA for 4 inch Stainless Steel
Aeration Air service line).
8. ______ Call out valve size, valve type, and fittings (ex: 12-PV for 12 inch plug valve)
9. ______ Include a standard Process Mechanical Details sheet(s).
MECHANICAL SHEETS (If Applicable)
1. ______ Include a General Mechanical Notes sheet(s). Notes shall include applicable codes and
regulations.
2. ______ Include a Legends & Abbreviations sheet if required.
3. ______ Include an overall Mechanical Plan sheet. This sheet shall include pertinent HVAC and Plumbing
sheets.
4. ______ Include separate sheet(s) for HVAC equipment. Sheet shall show locations of HVAC equipment,
clearances from other equipment, and include an HVAC equipment schedule.
5. ______ Include separate sheet(s) for Plumbing equipment, piping, fixtures, and fittings. When required,
plumbing sheets shall also include Plumbing Equipment schedule.
6. ______ Include a standard Mechanical Details Sheet.
ELECTRICAL SHEETS (If Applicable)
Depending on the nature of the project, it may be possible to combine some of these sheets.
1. ______ Include a sheet(s) for General Electrical Notes.
2. ______ Include a Legends & Abbreviations sheet if required.
3. ______ Include an Electrical Site Plan as required.
4. ______ Include an Area Classification Plan.
5. ______ Include One Line drawings for the project.
6. ______ Include a Power and Instrumentation Plan.
7. ______ Include Riser Diagrams.
8. ______ Include Electrical Plan Sheets for each affected area.
9. ______ Include a Grounding Plan.
10. ______ Include Light Fixture Plan Sheets for each affected area.
11. ______ Include Electrical Plans for each affected area or process unit.
12. ______ Include Panelboard and Fixture Schedules if required.
13. ______ Include a separate sheet(s) for standard Electrical Details.
Appendix B Plan Review Checklist
Appendix B-10
INSTRUMENTATION & CONTROL SHEETS (If Applicable)
Depending on the nature of the project, it may be possible to combine some of these sheets.
1. ______ Include a sheet(s) for General Instrumentation & Control Notes.
2. ______ Include a Legends & Abbreviations sheet if required.
3. ______ Include a Systems Architecture sheet(s) if required.
4. ______ Include a P&ID sheet(s) if required.
5. ______ Include a sheet(s) for Loop Diagrams if required.
6. ______ Include a sheet(s) for standard Instrumentation and Controls Details.
STANDARD AND SPECIAL DETAILS
1. ______ Appropriate City of Shreveport Standard Details included.
2. ______ Special Details showing dimensions, material requirements, and other information necessary for
construction.
3. ______ Additional Standard Details by the Design Engineer to cover the scope and requirements of the
project.
EROSION CONTROL/ STORMWATER POLLUTION PREVENTION PLAN LAYOUT SHEET
1. ______ North arrow and scale.
2. ______ Silt fence length and location called out.
3. ______ Project limits.
4. ______ Project clearing limits.
5. ______ Existing contours.
6. ______ Stockpile areas are indicated on plan.
7. ______ Construction entrances are indicated.
8. ______ Best Management Practices locations and details.
Appendix B Plan Review Checklist
Appendix B-11
COMMENTS AND NOTES
Appendix C-1
Appendix C
References Design of Wastewater and Storm water Pumping Stations, Water Environment Federation
Manual of Practice (FD-4), 1993
Recommended Standards for Wastewater Facilities, Great Lakes-Upper Mississippi River
Board of State and Provincial Public Health and Environmental Managers, 2004
Sewer System Infrastructure Analysis and Rehabilitation, EPA Publication (EPA/625/6-
91/030), 1991
Existing Sewer Evaluation and Rehabilitation, Water Environment Federation Manual of
Practice(FD-6), 2009 (3rd Edition)
The Guide to Short Term Flow Surveys of Sewer Systems (Water Research Centre
Engineering), 1987
The National Association of Sewer Service Companies Manual of Practice, 1995
Louisiana State Sanitary Code
City of Shreveport Water and Sewer Ordinances
City of Shreveport Fire Code
City of Shreveport Plumbing Code
City of Shreveport Standard Specifications
Shreveport Management Standards, Appendix 4.9B
Hydraulic Institute Standards
National Electrical Code
International Fire Code
Nation Fire Protection Agency
Louisiana Plumbing Code
Trenchless Technology Pipeline and Utility Design, Construction and Renewal 2005
ASTM A536 – Standard Specification for Ductile Iron Castings
ANSI A21.51 – Ductile Iron Pipe, Centrifugally Cast, for Water
AWWA Standards C51, C111, C115, C151, C512, C900, C905, C906, M22, M51
SSPWC Section 500
Appendix D-1
Appendix D
Design Phases
Key milestones of design phases are identified in this document. These milestones mark the
achievement of certain design goals which accompany delivery of pertinent documents. These
milestones are a conjunction of the City’s procedures and generally practiced standards.
Preliminary Design - 30% Completion The following activities occur during this phase of design:
The Design Engineer along with their key personnel shall conduct a kick-off meeting with the
City to review the scope of services, gather relevant data, and to understand the City’s
requirements and protocols.
The Design Engineer shall familiarize themselves with applicable codes, regulations and
requirements set forth by pertinent governing bodies. Where required, the Design Engineer
shall apply for pertinent permits, approvals and conduct environmental reviews.
The Design Engineer shall visit the site(s), and investigate existing survey and geotechnical
information, right-of-way maps, soil reports, master plans, field/lab data, record drawings and
all relevant technical reports in preparation for the design work.
During site visit(s), the Design Engineer shall verify that the current field conditions match the
record drawings.
The Design Engineer shall assist the City with Public Hearings if required. The Design Engineer
shall conduct additional Topographic Surveys, Geotechnical tests, and Special Investigations
(ex: pipeline inspections) as identified in the Scope of Services or as agreed upon during the
kick-off meeting.
The Design Engineer shall prepare all related calculations (Hydraulic, Process, Structural,
Electrical, etc)
If part of the scope, the Design Engineer shall evaluate design alternates available, along with
life-cycle cost estimates for each alternate.
The Design Engineer shall prepare preliminary plans (30% plans) based on the data gathered
and the calculations performed.
The Design Engineer shall prepare preliminary specifications for the design. A Table of Contents
(TOC), and an annotated outline of the specifications will be considered acceptable at this stage.
The Design Engineer shall submit the following documents to the City:
- A Design Criteria report as identified elsewhere in this manual. This may also be termed
‘Design Basis Memo’ or a ‘Preliminary Design Report’. This report shall include the
Appendix D Design Phases
Appendix D-2
following preliminary drawings: site layouts, Process Flow Diagrams (PFDs), Piping and
Instrumentation Diagrams (P&IDs), and Hydraulic Profiles. Preliminary Right of Way
(ROW) maps, sketch of survey lines, Geotechnical reports, all design calculations, and
results of special investigations shall also be included in this report. All design calculations
shall list the method used, assumptions made, values of constants used, and pertinent
references. If identified in the Scope of Services, this report shall also include design
alternates along with cost estimates for each alternate.
- 30% Plans that include the following preliminary plans: general sheets, standard details as
applicable to the project, site layouts, drainage and erosion control sheets, hydraulic
profiles, process mechanical sheets, PFDs, P&IDs, Instrumentation and Control (I&C) sheets,
pipe line routing concept with plan and profile views, and conceptual sheets by other
disciplines including mechanical, structural and electrical.
- A Quality Assurance/Quality Control (QA/QC) certification stating that all submittals have
been thoroughly reviewed by their QA/QC team, in accordance with their approved Quality
Management (QM) plan, for quality, accuracy, and scope. The Design Engineer shall include
copies of the QA/QC review documents and pertinent tracking sheets.
- 30% Design Specifications.
- A Class 4 (per Association for the Advancement of Cost Engineering or AACE) Opinion of
Probable Construction Cost (OPCC) estimate and an updated project schedule.
- The Design Engineer shall participate in a ‘30% Design Review’ meeting (also termed 30%
Plan-In-Hand meeting) with their Key Personnel and the City to discuss the City’s review of
the 30% design documents (30% Plans and Specifications).
Design Phase Sequence (condensed)
Design Development - 60% Design Completion Upon obtaining the final review comments from the City for 30% Design, Design Development or 60%
Design is considered to have started. The following activities are anticipated at this stage:
The Design Engineer shall update the design documents based on the City’s review comments
and design development.
Operability (with the City’s pertinent Operations team), Constructability and Value Engineering
reviews shall be conducted by the Design Engineer prior to submitting design documents.
Project Kick-Off
30% Design
Review Meeting
Design Criteria
Report
Finalize Design
Criteria
30% Design Documents,
Calculations, Class 4 cost estimate,
Updated Project Schedule
Appendix D Design Phases
Appendix D-3
All survey efforts and ROWs shall be completed during this phase.
Any remaining or newly identified design calculations shall be completed.
Generally accepted design achievement levels for this phase are:
- Process Mechanical, Civil, Architectural and Geotechnical – minimum 75% complete.
- Structural, Electrial and I&C – minimum 60% complete.
- Building Mechanical – minimum 50% complete.
The Design Engineer shall submit the following documents to the City:
- Technical Reports if identified in the Scope of Services.
- Technical Memorandum identifying updates or changes to the design based on the
Operability, Constructability and Value Engineering review.
- Pre-Final Design Calculations.
- Finalized ROW maps shall clearly show all takings and servitudes required.
- 60% Plans with finalized site layouts, grading plans; coordinated plans. Process Mechanical
sheets, Hydraulic Profiles and Civil sheets shall be close to completion. All conflicts
(underground utilities, structures, etc) shall be identified at this juncture, and addressed.
Pipe routing, shall be near complete.
- 60% Specifications, including the ‘Front End’ documents. The Design Engineer shall verify
project and bidding requirements with the City when preparing the ‘Front End’ documents.
The Design Engineer is hereby notified that the City’s Standard Specifications may not be
applicable to all projects, therefore these specifications may need to be edited/updated as
required when incorporated.
- A Quality Assurance/Quality Control (QA/QC) certification stating that all submittals have
been thoroughly reviewed by their QA/QC team, in accordance with their approved Quality
Management (QM) plan, for quality, accuracy, and scope. The Design Engineer shall include
copies of the QA/QC review documents and pertinent tracking sheets.
- A Class 3 AACE cost estimate, and an updated project schedule shall be submitted along
with the 60% Plans and Specifications (60% design documents).
- The Design Engineer shall participate in a ‘60% Design Review’ meeting (also called 60%
Plan-In-Hand meeting) with their Key Personnel and the City in attendance to discuss the
City’s review of the 60% design documents.
Appendix D Design Phases
Appendix D-4
Design Phase Sequence (condensed)
Pre-Final Design - 90% Design Completion The Pre-Final design phase starts upon the Design Engineer receiving finalized review comments
subsequent to the 60% Design Review meeting. The following criteria shall be met at this stage:
The Design Engineer shall update the design documents per the City’s 60% review comments.
Overall project realization levels for this phase are:
- Process Mechanical, Hydraulics and Geotechnical – 100% complete.
- Structural, Mechanical, Architectural, Site Civil, and I&C – over 90% complete.
- Electrical – Over 80% complete.
The Design Engineer shall submit permit applications to various governing agencies per project
requirements.
The following documents shall be submitted to the City during this phase:
- Final design calculations per the requirements set forth in this document.
- 90% design documents (90% Plans and Specifications) for the City’s review. At this stage
the design is almost complete, and therefore the design documents shall be complete with
the exception of few updates, and coordination issues with other disciplines. The
Specifications shall be coordinated with the Plans so as to provide uniformity.
- A Quality Assurance/Quality Control (QA/QC) certification stating that all submittals have
been thoroughly reviewed by their QA/QC team, in accordance with their approved Quality
Management (QM) plan, for quality, accuracy, and scope. The Design Engineer shall include
copies of the QA/QC review documents and pertinent tracking sheets.
- A 90% Review Check List (included in this manual) shall be completed and submitted along
with the 90% design documents.
- A list, including but not limited to, required submittals, spare parts, warranty terms.
- A Class 2 AACE cost estimate, and a project schedule shall be submitted along with the 90%
design documents.
30% Design
complete
Submit Technical Reports
(if required), ROW maps
60% Design
Documents, Class 3
OPCC, updated
project schedule
60% Design
Review Meeting
Appendix D Design Phases
Appendix D-5
Design Phase Sequence (condensed)
Final Design -100% Design Completion At this stage all design is complete, and all of the City’s review comments have been incorporated. The
Design Engineer shall apply for any additional permits that may be required. Prior to issuing 100%
design documents, the Design Engineer shall submit 95% design documents for the City’s review. The
95% design set shall be complete in all aspects with the exception of the final stamp and seal, and will
be used by the City to do a final cross-check.
After approval of the 95% design documents, the Design Engineer shall submit the following:
- A completed final Review Check List (attached with this manual).
- Final design documents (100% Plans and Specifications). These shall be stamped and
sealed in accordance with the requirements of Louisiana Professional Engineering and Land
Surveying (LAPELS) board. The final design documents shall be accompanied by a written
certification from the Design Engineer stating that a detailed check was performed on all
previous review comments, and were addressed.
- A list, including but not limited to, required submittals, spare parts, warranty terms.
- An updated Class 4 cost estimate (final) shall be submitted along with the final design
documents.
Design Phase Sequence (condensed)
60% Design
complete
Submit Permit
Applications
90% Design Documents,
Final Calculations, Class
2 OPCC, updated project
schedule, 90% Review
Checklist, List of
submittals, spares,
warranty terms, etc.
90% Design Review
Meeting
90% Design
complete
Submit Permit
Applications
95% Design
Documents
100% Design Documents,
Quality Review
Certification, Final Class 2
OPCC, List of submittals,
spares, warranty terms, etc.
100% Review Checklist.
Appendix D Design Phases
Appendix D-6
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