Recap/Highlights – Part 2by Bill Chavez, PUG TreasurerApril 17, 2012

NASTT’s 2012 No-Dig Show

Paper A-5-03: Lesson Learned about External Corrosion that leads to a 9’4”x8’4” Influent Sewer Collapse

Steve Brian, Renni Zhao, DC Water, Washington, DC

J.W. Marshall & Associates Inc. Abingdon, MD

NDT Corporation, Worcester, MA

Concrete Deterioration 3-in interior and 7-in outer portion. 9’ x 8’concrete sewer serving Counties Virginia & MarylandA pipe investigation program developed:

Visual InspectionSoil chemistry testStray current evaluationNondestructive sonic/ultrasonic testingGround penetrating radar testing

Objectives of the programWhat are the major causes of failureWhat are the causes of external pipe corrosionWhat external causes contributed to the failure

Paper A-5-03: Lesson Learned about External Corrosion that leads to a 9’4”x8’4” Influent Sewer Collapse

Steve Brian, Renni Zhao, DC Water, Washington, DC

J.W. Marshall & Associates Inc. Abingdon, MD

NDT Corporation, Worcester, MA

Soil chemistry testing: soil pH, redox potential, soil box resistivity, sulfate ion concentration, chloride ion concentration External Non-destructive test:

Sonic/ultrasonic used, 1 ft interval. Pulse-echo testing, stress waves detected by sensorsProvides concrete compressive strength, thickness, location of delamination and cracking.

Ground Penetration Radar (GPR)Pulsed electromagnetic signal to detect changes in material electrical properties, thickness of concrete/rebarUse 900 & 1600 MHz GPR antennas

Paper A-5-03: Lesson Learned about External Corrosion that leads to a 9’4”x8’4” Influent Sewer Collapse

Steve Brian, Renni Zhao, DC Water, Washington, DC

J.W. Marshall & Associates Inc. Abingdon, MD

NDT Corporation, Worcester, MA

Conventional visual inspection might be misleading since surfaceprofile seems smooth and not out of the ordinary

Cracking where high overburden and H2S attack occurred. Micro cracking increase exposed surface.

Sonic/ultrasonic can measure pipe thickness & evaluate integrityincluding hidden cracks & delaminations. Complement inspection

NASSCO PACP code system better on smaller pipes. Larger pipes need to consider evaluating interior and exterior of pipe

DCWATER rehabilitates pipes with exposed rebar and/or concrete cracking. However, criteria for inspection and rehabilitation should include entire pipe wall rather than only interior surface

New inspection protocol for large diameter sewer inspection has been developed.

At the end, 1,000 ft of the influent sewer was relined

Exhibit Hall: SewerVue – In-pipe GPR

SewerVue,

4650A Dawson St., Burnaby, BC, Canada

1-888-973-9378

www.sewervue.com

Underground pipe inspectionRemotely operated surveyor robot merges CCTV data with Ground Penetrating Radar measurementsIdentifies: pipe wall thickness, composition defects, rebar cover, locate cracks, voids and cavities outside non-ferrous pipesGPR equipped with two high frequency antennaeEquipment can be adjusted pipe diameters 18 – 30-in

Paper B-4-01: Lateral Rehabilitation Options and their Cost-Benefit Comparison

James Shelton, PE, Malcolm Pirnie, The Water Division of Arcadis, Wilmington, DE

David Hofer, PE, New Castle County Dept of Special Services, New Castle, DE

New Castle County, DESystem contains 1,800 miles of sewer mains serving 112,000 customers. Built during 40’s, 50’s, 60’s of terracota pipe & brick MHs. Problems of the System: broken/collapsing pipes & MHs, chronic root intrution/blockages, and leaking pipe joints & MHsMajor problem: rainfall derived Inflow & Infiltration, undersized interceptor/PSMajor increase in: leakage, basement backups, customer

complaints/clean up costs, MH overflowDelaware Dept Natural Resources & Environmental Conservation Secretary Order: 50% reduction of RD I&I

Brandywine Sewer Rehabilitation Program:Laterals must be rehabilitated to achieve aggressive I&I goalsMalcolm Pirnie based on 6 years experience trialing & installingvarious technology developed Lateral Technology Cost-Benefit Tool

Paper B-4-01: Lateral Rehabilitation Options and their Cost-Benefit Comparison

James Shelton, PE, Malcolm Pirnie, The Water Division of Arcadis, Wilmington, DE

David Hofer, PE, New Castle County Dept of Special Services, New Castle, DE

Assessment Cost-Benefit ConceptBenefit Weightings:

Structural Improvement 15%, tap improvements & lateral improvementsLeakage Reduction 75%, Improvements: annular space/tap, riser, transition, ROW to houseOperability Improvement 10%, cleanouts and O&M value

Each technology is graded on its ability to deliver benefits under each of these nine categories:

Paper B-4-01: Lateral Rehabilitation Options and their Cost-Benefit Comparison

James Shelton, PE, Malcolm Pirnie, The Water Division of Arcadis, Wilmington, DE

David Hofer, PE, New Castle County Dept of Special Services, New Castle, DE

Service Life Cycle – period of time until weakest component of a technology fails. Opinion-based specific to each engineer and utility

Costs for each technology – sum of costs required to fully install each item (include removing roots in laterals, etc.)Life cycle cost is divided by total value of a technology to determine Cost-Benefit number whose value is given in dollars per benefit point

Paper B-4-01: Lateral Rehabilitation Options and their Cost-Benefit Comparison

James Shelton, PE, Malcolm Pirnie, The Water Division of Arcadis, Wilmington, DE

David Hofer, PE, New Castle County Dept of Special Services, New Castle, DE

The power of this tool: what-if and sensitivity analyses regarding benefit values, life cycle periods, cost changes when evaluatingtechnologies for rehabilitation

Exhibit Hall: SEWPER COAT

Kerneos Aluminate Technologies

1316 Priority Ln Chesapeake, VA 23324

1-877-KERNEOS

www.sewpercoat.com

Corrosion resistant liningCorrosion-resistant protection against H2SProvides High-strength >6K psi within 24 hoursInhibits bacterial activity, minimizing production of Sulfuric Acid100% pure calcium aluminate in cement and aggregateDesigned to be spray applied with:

dry-gunite or low-pressure – use SewperCoat 2000 HS regularwet shotcrete equipment – use SewperCoat PG

Installation thickness 1/2-inch in manhole; 1-inch more critical structures

Paper A-5-04: Advances in Water Pipeline Condition Assessment

Cliff Jones and Dave Lewis, Wachs Water Services

1-800-525-5821

Empirical study of 750,000 assets over 10 year period. Each mile of distribution main has 18 valves and 8 hydrants on average. Results of observations:

40% of all water valves are unusable (cannot be located in 10 min)Attempt to close increase number of valves before a line can be isolatedResulting in additional delay, disruption and cost12% Hydrants are inoperable/inadequate flow11% valves are paved over9% distribution valves in wrong positionTransmission valves found shut 9% of the timeStudy indicates statistics are fairly consistent across nation

Paper A-5-04: Advances in Water Pipeline Condition Assessment

Cliff Jones and Dave Lewis, Wachs Water Services

1-800-525-5821

Why 40% of valves unusable are a concern? Per AWWA & EPA, 27 to 58 main breaks per year, per 100 miles. Large diameter break – average cost $500K. It includes flooding, loss of water, repair of pipeline, wasted chemicals, pumping cost, customer complaint, traffic disruption, bad publicity, etc.These costs increase the longer the main break continuesAverage margin of error on the location of valves is 27 ft – 27 ft radius crew needs to search

Paper A-5-04: Advances in Water Pipeline Condition Assessment

Cliff Jones and Dave Lewis, Wachs Water Services

1-800-525-5821

How utilities can address situation? Create typical matrix analysis of pipeline risk factors: Criticality & Condition rating Paper suggests asset mgmt approach should include understanding condition of control points (valves) & impact of improve system could have on consequence of failureObtain real world field data on condition of assets, see modified 10 step process for asset mgmt:

Paper A-5-04: Advances in Water Pipeline Condition Assessment

Cliff Jones and Dave Lewis, Wachs Water Services

1-800-525-5821

Authors contend that better results can be obtained by: Undertaking an inventory of assetsAssessing condition of assetsAssessing criticality/consequence of failureDetermine appropriate maintenance policy/practicesAsset mgmt program become more relevant & manageable

Case study – City of Baltimore: City had 64,000 valves and 21,000 hydrantsValves: 5,000 wrong position, 3,200 paved over, 3,000 broken, 606 frozen, 603 misaligned, 4,500 could not be located immediately Wachs Water Service working with City was able to increase

usability from 43% up to over 90% by: raising paved over valves,repairing damaged box structures or valves, and locating “lost”valves.

THANK YOU!

All papers can be purchased from the NASTT website at www.nastt.org