Plumbing Design Handouts

MASTER PLUMBER REVIEW

Plumbing Design and Installation

PowerHouse Review Center

PLUMBING CONCEPTS

Part 1: Fundamentals of Plumbing Design and Installation

Part 2: Process, Design Criteria and Computations

PLUMBING

the art and technique of installing pipes, fixtures, and other apparatuses in buildings for bringing in the supply of liquids, substances and/or ingredients and removing them; and such

water, liquid and other carried-wasteshazardous to health, sanitation, life and property; also the

pipes and fixtures after installationi.e., the plumbing system

PLUMBING

Plumber title of the person who is skilled in plumbing

Plumbarius who worked in the field of sanitation in

ancient Rome

Plumbum means lead, the material the ancient

Rome used in plumbing

C o m p o n e n t s

WATER DISTRIBUTION SYSTEM

FIRE PROTECTION SYSTEM

PLUMBING FIXTURES

SANITARY DRAINAGE SYSTEM

STORM DRAINAGE SYSTEM

FUEL GAS PIPING SYSTEM

PLUMBING SYSTEM

Water Supply PVC, GI, BI, PE, HDPE, Steel,

BI Black Iron

Storm/Drainage System PVC, GI/BI

Vent System PVC

Sewer/Waste System PVC, CI

Fire Protection GI, BI

Co

mp

on

en

ts &

Flo

w in

Wat

er

Syst

em

s:

SUPPLY

Water Mains,Storage Tanks

DISTRIBUTION

Pressure,PipingNetworks

USE

PlumbingFixtures

COLLECTION

Gravity,PipingNetworks

TREATMENT

Sewage Plants,NaturalPurification

SOURCE

Lakes, Rivers,Reservoirs

Treated waterreturned to theoriginal source

DISPOSAL

Sanitary andStorm Sewers

THE PLUMBING CYCLE

NATIONAL PLUMBING CODE OF THE PHILIPPINES

Book of Master Plumbers practicing their profession in the Philippines

22 Basic Principles of the Plumbing Code

7 Code of Ethics


Board Resolution No. 4, Series of 1999

History of Plumbing Practice

Basic Principles

Master Plumbers Code of Ethics

CHAPTERS:1. Administration

2. Definitions

3. General Regulations

4. Plumbing Fixtures


5. Inspections and Tests6. Water Supply and Distribution7. Excreta Drainage System8. Indirect Waste Piping, Wet-Vented Systems, and Special

Wastes9. Vents and Venting10. Traps and Interceptors11. Storm Drainage System12. House Drains and House Sewers13. Joints and Connections14. Quality of Weight Materials, Plumbing Materials and

Referenced Standards


Appendix A: Recommended Rules for Sizing the Water Supply System

Appendix B: Private Sewage Disposal Systems

Tables and Charts

OBJECTIVES OF PLUMBING IN BUILDINGS

1. To supply water to different parts of the building

2. To remove and discharge human wastes and other substances out of the building into the public sewer or septic tank

CONDITIONS FOR AN EFFECTIVE WATER SUPPLY IN BUILDINGS

1. Provide sufficient amount of water to supply each fixture

2. Prevent back flow of used water into the water supply system

WATER DISTRIBUTION IN BUILDINGS



THINGS TO CONSIDER IN THE PLANNING OF

WATER SYSTEM IN BUILDINGS

1. System must provide adequate supply of water, with adequate pressure up to the extremities of the system

2. System should be provided with sufficient valves and blow-offs to allow repair work without undue interruption of service

3. There should be no unprotected open reservoir, or cross connections with inferior water system to enter the system

4. Water system should be tight against leakage. Branches or connections should not be submerged in surface water or to any source of contamination

5. System design shall afford effective circulation of water with minimum number of dead end mains

6. System shall be guarded against contamination resulting from repair works, replacement or extension of the mains

7. When new are installed, or old mains repaired, they should be filled with strong chlorine solution of 40-60 mg/L for at least 24 hrs., and then flushed with water supplied normally from the main.

8. As much as possible water main should be laid above the elevation of concrete sanitary sewers, or crossover points, and at least 3m horizontally from such sanitary sewer when they are parallel. Otherwise, the sewer main must be

encased in concrete

CLASSIFICATION OF PUBLIC WATER DISTRIBUTION SYSTEM

1. DIRECT PRESSURE DISTRIBUTION

2. INDIRECT PRESSURE DISTRIBUTION

DIRECT PRESSURE DISTRIBUTION

Obtain its water supply through a large intake pipe, installed in the lake basin extended down the water;

Water is then drawn from the lake to a receiving well by force of gravity, passing through the filtration plant

The water inside the reservoir is pumped by a centrifugal, or piston pump into the water main with sufficient pressure to serve specific needs

INDIRECT PRESSURE DISTRIBUTION

Water drawn from a drilled distribution is done by indirect pressure using a turbine pump mounted on top of the standpipe extended down the well below the water table

HOUSEHOLD WATER SUPPLY

Water is conveyed from the main to the

household or buildings through:

1. House Service

2. Riser

3. Branches

House Service

pipe connection from the water main to any source of water supply to the building served

Riser

Vertical supply pipe which extend upward from one floor to the next.

Branches

Horizontal pipes that serve the faucets or fixtures

Water Main

Corporation Stop

Stop Box

Curb Stop

Meter Stop

House Service Pipe

Water Meter

Corporation Stop or CockCurb StopMeter Stop

Water Supply

Water Main

refers to the public water connection which are laid underground along the streets where the house service is connected

Corporation Stop

serves as a control of the water service, and a shut-off when service is disconnected

Curb Stop

installed between the curb & the sidewalk line to serve as control stop of the service between the curb and the building

Meter Stop

controlling stop of the entire water supply of the building

Water Meter

device used to measure the amount of water that passes through the water service

TYPES OF COLD WATER SYTEM

1. NORMAL PRESSURE FROM THE PUBLIC MAIN

2. OVERHEAD FEED SYSTEM

3. AIR PRESSURE DISTRIBUTION SYSTEM

Overhead Feed Distribution System

Overhead Feed System

This supplies water to plumbing fixtures by

means of gravity.

Advantages:

1. Water supply distribution is not affected by the peak load hour even if pressure at water main is low.

2. Power interruptions doesnt affect water supply

3. During break down of pumps and their repairs, water supply is not affected.

Disadvantages:

1. Water inside tank is exposed to the natural elements of weather, subject to contamination

2. Water distribution unit has many working parts that require higher maintenance cost

3. Pumping unit and the entire installation throughout the building occupies valuable spaces.

4. Requires stronger foundation and other structures to sustain heavy load of the tank and its water content

Direct Upfeed System

Used on tall buildings that could not be served by the street main

Operates in sequence according to the volume of demand:

When water demand is small, small (jockey) pump operates;

As water demand increases, the 2nd larger pump starts automatically to replace operation of the small pump

For peak demands, the largest pump operates with full capacity to supply the entire building

Only one pump operates at a time depending on the volume of water demand

Direct Upfeed System

Advantages

1. Eliminate the construction of large house water tank

2. Avoid cost of heavy structures to carry the house tank

3. Eliminate periodic cost

Air Pressured Water Distribution System

Distribution system where compressed air is used as the delivery agent

Advantages:

1. Has compact pumping system requiring limited space

2. Water chamber being air-tight makes the system as sanitary one

3. Oxygen in the CA serves as purifying agent making water more palatable

Air Pressured Water Distribution System

Advantages

4 Economical because it uses small pipe & fitting sizes; less maintenance/construction cost

5 Acceptable to small and tall buildings

Disadvantage:

1 Power interruption cuts water supply

4 Mechanical Devices used in Air Pressurized Water Supply System

1. Storage Tank

2. Single or Duplex centrifugal pump

3. Air compressor

4. Automatic pressure control switch

Friction in Water Supply

the resistance produced by the flowing water with the fittings and interior surface of the pipe

How to minimize friction:1. Pipes should be installed straight and direct2. Use of fittings, stops, turns, offset and traps

should be minimized3. Pipes with plain and smooth surface should be

used4. Fittings and joints must connected properly

Normal Pressure

refers to the pressure range measured over 24 hours

Normal Pressure

30-40 psi

Pressure Lower than Normal Pressure

results to insufficient flow of water

Pressure greater than 50 psi

may cause pipe hammering or even bursting of pipes

Pressure Reducing Valve

valve used to avoid excessive water pressure by keeping pressure constant at 40 psi or can be reset to other pressure desired

Critical Pressure

maximum and minimum pressure at which proper function of the water supply can be maintained

MAXIMUM PROBABLE DEMAND

Refers to the MAXIMUM WATER DISCHARGE OF FIXTURES in terms of Fixture units

THE MAXIMUM DEMAND OF WATER is equal to the TOTAL FIXTURES UNITS in the plumbing system

One unit is valued at 8 gals of water discharge per minute interval

Illustration:

A residential house has 3 water closets, 3

lavatories, 1 kitchen sink, and 3 shower baths.

Determine the maximum demand.

PROBABLE DEMANDOR PEAK LOAD

The fewer the number of fixtures installed,

the higher the percentage of probability of their

simultaneous use;

The greater the number of fixtures installed,

the lower the percentage of probable simultaneous use.

PROBABILITY OF SIMULTANEOUS OF FIXTURES

Number of Fixtures % of Simultaneous Use

1 to 5 50% to 100%

6 to 50 25% to 50%

51 or more 10% to 25%

PROBABLE DEMAND does not exceed 25% of the Maximum Water Demand

Illustration:

Determine the probable demand of the following

Fixtures installed: 2 water closets, 1 lavatory, 1

bathtub, 1 shower valve, 1 kitchen sink.

TYPES OF HOT WATER SYTEM

1. UPFEED AND GRAVITY RETURN SYSTEM

2. DOWNFEED AND GRAVITY RETURN SYSTEM

3. PUMP CIRCUIT SYSTEM

With a continuing network of pipes to provide constant circulation of water

Hot water rises on its own & does not need any pump for circulation

Hot water is immediately drawn form the fixture any time

Provided economical circulating return of unused hot water

Larger pipe is installed at thetop of the riser & the diminishing sizes passes through the lowerfloors of the building

Upfeed and Gravity Return System

Hot water rises on to the highest point of the plumbing system and travels to the fixtures via gravity (closed pipe system)

Water distribution is dependent on the expansion of hot water & gravity.

Larger pipe is installedat the bottom of theriser & the diminishing sizes passesthrough the upperfloors of the building

Downfeed and Gravity Return System

For a more efficient circulation of hot water to the upper floor levels of multi-storey buildings

Pump Circuit System

Water Tanks & Cisterns

Hot Water ConsumptionKIND OFBUILDING

GALLONS PERPERSONS PER HOUR

Office Buildings

School Buildings

Apartment Buildings

Hotels

Factories

Residential

4 to 5

2 to 3

8

8 to 10

4 to 6

10

Working Load of Hot Water Systems

KIND OF BUILDING AVERAGE WORKINGLOAD

School, Office & Industrial types

Apartments & Residences

Hotels & Restaurants

25%

35%

50%

Hot Water Space Heating System

Hot Water Supply System

Water is confined within a system at low temperature

Not a closed system which operate on much higher temperature

Protection of Hot Water Tank:

System Relief Valve

Temperature & Pressure Relief

Used for Hot Water Space Heating System

Used for Hot Water Supply System

TYPES OF WATER HEATING SYSTEM

FLUID COMPUTATIONS



Water / Wastewater

Conversion

Example:

Convert cubic feet to gallons.

Gallons = Cubic Feet (ft3) x gal/ft3

ProblemHow many gallons of biosolids can be pumped to a digester that has 3600 cubic feet of volume available?

Convert gallons to pounds.

pounds ( lb ) = Gallons (gal) x 8.34 lb/gal

Problem

If 1650 gallons of solids are removed from the primary

settling tank, how many pounds of solids are removed?

Example:

Convert milligrams/liter to pounds.

key point: For plant operations, concentrations in milligrams per liter (mg/L) or parts per million (ppm) determined by laboratory testing must be converted to quantities of pounds, kilograms, pounds per day, or kilograms per day.

Pounds = Concentration (mg/L) x volume (MG)

x 8.34 lb/mg/L/MG

Problem

The solids concentration in an aeration tank is 2580 mg/L. The aeration tank volume is 0.95 MG. How many pounds of solids are

in the tank?

Example:

Convert milligrams per liter to pounds per day.

Pounds/day = Concentration (mg/L) x flow (MGD)

x 8.34 lb/mg/L/MG

Problem

How many pounds of solids are discharged per day when the plant effluent flow rate is 4.75 MGD and the effluent solids concentration is 26 mg/L?

Example:

Convert milligrams per liter to kilograms per day.

kg/day = Concentration (mg/L) x volume (MG)

x 3.785 kg/mg/L/MG

Problem

The effluent contains 26 mg/L of BOD5. How many kilograms per day of BOD5 are discharged when the effluent flow rate is 9.5 MGD?

Example:

Convert million gallons per day (MGD) to gallons per minute (gpm).

Flow = Flow (MGD) x 1,000,000 gal/MG

1440 min/day

Problem

The current flow rate is 5.55 MGD. What is the flow rate in gallons per minute?

Example:

Convert million gallons per day (MGD) to gallons per day (gpd)

Flow = Flow (MGD) x 1,000,000 gal/MG

Problem

The influent meter reads 28.8 MGD. What is the current flow rate in gallons per day?

Example:

Convert million gallons per day (MGD) to cubic feet per second (cfs)

Flow (cfs) = Flow (MGD) x 1.55 cfs/MGD

Problem

The flow rate entering grit channel is 2.89 MGD. What is the flow rate in cubic feet per second?

Example:

Problem

A liquid chemical with a specific gravity (SG) of 1.22 is pumped at a rate of 40 gpm. How many pounds per day are being delivered by the pump?

Example:

Temperature Conversions

Most water/wastewater operators are familiar with the formulae used for Fahrenheit and Celsius temperature conversions:

oC = 5/9 (oF 32)oF = 9/5 (oC) + 32

The difficulty arises when one tries to recall these formulae from memory. Probably the easiest way to recall these important formulae is to remember three basic steps for both Fahrenheit and Celsius conversions:

Add 40o

Multiply by the appropriate fraction (5/9 or 9/5) Subtract 40o

Suppose that we wish to convert 240oF to Celsius. Using the three-step process, we proceed as follows:

Step 1 : add 40o

240o + 40o = 280o

Step 2 : multiply 280o by either 5/9 or 9/5.

Because the conversion is to the Celsius scale, we will be moving to a

number smaller than 280. Through reason and observation, obviously, if 280 were multiplied by 9/5, the result would be almost the same as multiplying by 2, which would double 280 rather than make it smaller. If we multiply by 5/9, the result will be about he same as multiplying by . Because in this problem we wish to move to a smaller number, we should multiply by 5/9:

(5/9) (280o) = 156.0oC

Example:

Step 3 : now subtract 40o.

156.0o - 40o = 116.0oC

Thus, 240oF = 116.0oC

Convert 22oC to Fahrenheit.

Example:

FLOW

Flow is expressed in many different terms in the English system of measurement. The most commonly used flow terms are as follows:

gpm gallons per minute

cfs cubic feet per second

gpd gallons per day

MGD million gallons per day

In converting flow rates, the most common flow conversions are 1 cfs = 448 gpm and 1 gpm = 1440 gpd. To convert gallons per day to MGD, divide the gpdby 1,000,000. For example, convert 150,000 gallons to MGD:

150,000 gpd = 0.150 MGD

1,000,000

In some instances, flow is given in MGD but is needed in gpm. To make the conversion (MGD to gpm), two steps are required.

Step 1: convert the gpd by multiplying by 1,000,000.

Step 2: convert to gpm by dividing by the number of minutes in

a day (1440 min/day).

Problem

Convert 0.135 MGD to gpm.

Example:

In determining flow through a pipeline, channel, or stream, we use the following equation:

where

Q = cubic feet per second (cfs)

V = velocity in feet per second (ft/second)

A = area in square feet (ft2)

Problem

Find the flow in cubic feet per second (cfs) in an 8-inch line if the velocity is 3

feet per second.

Example:

Problem

Find the flow in gpm when the total flow for the day is 75,000 gpd.

Example:

Problem

Find the flow in gpm when the flow is 0.45 cfs.

Example:

DETENTION TIME

Detention time is the length of time water is retained in a vessel or the period from the time the water enters a settling basin until it flows out the other end. When calculating unit process detention times, we are calculating the length of time it takes the water to flow through that unit process. Detention times are normally calculated for the following basins or tanks:

Flash mix chambers (seconds)

Flocculation basins (minutes)

Sedimentation tanks or clarifiers (hours)

Wastewater ponds (days)

Oxidation ditch (hours)

To calculate the detention period of a basin, the volume of the basin must first be obtained. Using a basin 70 ft long (L), 25 ft wide (W), and 12 ft deep (D), the volume (V) would be:

V = L x W x D

V = 70 ft x 25 ft x 12 ft

V = 21,000 ft3

Gallons = V x 7.48 gal/f2

Gallons = 21,000 x 7.48 = 157,080 gallons

If we assume that the plant filters 300 gpm, then we have 157,080 / 300 = 524 minutes, or roughly 9 hours, of detention time. Stated another way, the detention time is the length of time theoretically required for the coagulated water to flow through the basin.

Key point: If the detention time is desired in minutes, then the flow rate used in the calculation should have the same time frame (cfm or gpm, depending on whether tank volume is expressed as cubic feet or gallons). If detention time is desired in hours, then the flow rate used in the calculation should be cfh or gph.

If chlorine is added to the water as it enters the basin, the chlorine contact time (CT) would be 9 hours. That is, to determine the CT (concentration of free chlorine residual x disinfectant contact time [in minutes] used to determine the effectiveness of chlorine), we must calculate detention time.

Key point: True detention time is the T portion of the CT value.

Detention time, of course, is calculated in units of time. The most common are seconds, minutes, hours, and days. Examples of detention time equations where time and volume units match include:

Detention time (sec) = volume of tank (cu ft)flow rate (cfs)

The simplest way to calculate detention time is to divide the volume of the

container by the flow rate into the container. The theoretical detention time of a container is the same as the amount of time it would take to fill the container if it were empty. For volume, the most common units used are gallons; however, on occasion, cubic feet may also be used. Time units will be in whatever units are used to express the flow. For example, if the flow is in gpm, the detention time will be in days, If, in the final result, the detention time is in the wrong time unit, simply convert to the appropriate units.

Detention time (days) = volume of tank (gal)flow rate (gph)

Problem

The reservoir for the community holds 110,000 gallons. The well will produce 60 gpm. What is the detention time in the reservoir in hours?

Example:

Problem

Find the detention time in a 55,000-gallon reservoir if the flow rate is 75 gpm.

Example:

HORSEPOWER AND ENERGY COSTS

In water/wastewater treatment and ancillaries, horsepower is a common expression for power. One horsepower is equal to 33,000 foot pounds (ft-lb) of work per minute. This value is determined, for example, for selecting the pump or combination of pumps to ensure an adequate pumping capacity (a major use of calculating horsepower in water/wastewater treatment). Pumping capacity depends upon the flow rate desired and the feet of head against which the pump must pump (also referred to as effective height).

Calculations of horsepower are made in conjunction with many treatment plant operations. The basic concept from which the horsepower calculation is derived is the concept of work, which involves the operation of a force (lb) over a specific distance (ft). The amount of work accomplished is measured in foot-pounds:

ft x lb = ft-lb

The rate of doing work (power) involves a time factor. Originally, the rate of doing work or power compared the power of a horse to that of a steam engine. The rate at which a horse could work was determined to be about 550 ft-lb/sec (or 33,000 ft-lb/min). This rate has become the definition of the standard unit called horsepower.

Horsepower (hp)

Horsepower (hp) = power (ft-lb/min)

33,000 ft-lb/min/hp

As mentioned, in water/wastewater treatment the major use of horsepower calculation is in pumping stations. When used for this purpose, the horsepower calculation can be modified as shown below.

Water Horsepower (whp)

The amount of power required to move a given volume of water a specified total head is known as water horsepower.

whp = pump rate (gpm) x total head (ft) x 8.34 lb/gal

33,000 ft-lb/min/hp

Problem

A pump must deliver 1210 gpm to a total head of 130 feet. What is the required water horsepower?

Example:

Brake Horsepower (bhp)

Brake horsepower (bhp) refers to the horsepower supplied to the pump from the motor. As power moves through the pump, additional horsepower is lost from slippage and friction of the shaft and other factors; thus, pump efficiencies range from about 50% to 85%, and pump efficiency must be taken into account.

bhp = whp

pump efficiency (%)

Problem

Under the specified conditions, the pump efficiency is 73%. If the required water horsepower is 40 hp, what is the required brake horsepower?

Example:

Motor Horsepower (mhp)

Motor horsepower (mhp) is the horsepower the motor must generate to produce the desired brake and water horsepower.

mhp = brake horsepower

motor efficiency (%)

Problem

The motor is 93% efficient. What is the required motor horsepower when the required brake horsepower is 49.0 bhp?

Example:

ELECTRICAL POWER

On occasion, water/wastewater operators (especially senior

operators) must make electrical power calculations especially regarding electrical energy required/consumed during a period of time. To accomplish this, horsepower is converted to electrical energy (kilowatts), then multiplied by the hours of operation to obtain kilowatt-hours.

Kilowatt-hours = hp x 0.746 kW/hp x operating time (hr)

Problem

A 60-horsepower motor operates at full load 12 hours per day, 7 days a week. How many kilowatts of energy does it consume per day?

Given the cost per kilowatt-hour, the operator (or anyone else) may calculate the cost of power for any given period of operation.

Cost = power required/day x kW-hr/day x days/period x cost/kW-hr

Example:

PD 856 Chapter 17 - Sewage Collection and

Disposal, Excreta Disposal and Drainage



Section 3: Individual Excreta and Sewage Disposal System

3.1 Individual Excreta Disposal System Every plan and specifications for excreta disposal

system approved by the local health authority prior to construction.

The City/Municipal Building Official shall refer all applications for Sanitary (Plumbing) Permit to the Local Health Authority prior to issuance of building permit.

The privy recommended for use is the sanitary privy.

The sanitary privy shall be atleast one (1) meter square.


3.2 Individual Sewage Disposal System3.2.1 Installation Requirements When a public sanitary sewer is not available,

wastewater piping shall be provided with individual sewage disposal system of approve type and design.

The public sanitary sewer may be considered as not being available when such public sanitary sewer is located more than 100 meters from any proposed building on any lot or premises.


3.2 Individual Sewage Disposal System

3.2.2 Approval

The Local Health Authority may require any or all of the following information before Sanitary (Plumbing) Permit is issued.

Plot plan drawn to scale completely dimensioned, showing direction and approx slope of surface

Location of all present and proposed retaining walls, drainage channels, water supply lines and wells

Number of plumbing fixtures

Location of building sanitary sewer and individual sewage disposal system

A log of soil formations and ground water levels, together with a statement of water absorption characteristics of the soil


3.2 Individual Sewage Disposal System3.2.2 Disposal of Sewage Individual sewage disposal system utilizing leaching fields,

leaching beds, or leaching wells shall not be permitted where the depth to normal ground water or rock strata is less than 1.20 meters

A leaching system shall not be installed in an area where the texture, structure, and porosity of soil are not suitable as determined by a percolation test performed by a registered Civil/Sanitary Engineer.

No leaching tile file or bed shall be installed where percolation rate is less than 2.54 cm fall in water level in test holes in 60 minutes.

No seepage pit or leaching well shall be installed where percolation rate is less than 2.54 cm fall in water level in test holes in 30 minutes.

Section 4: Design and Construction of Septic Tanks, Leaching Tile Field and House Sewers

4.1 Septic Tank4.1.1 Design Capacity May be determined from the quantities of Sewage

Flow, based on adequate detention time interval resulting in efficient sedimentation.

For building with occupants, the number of persons to be served shall be computed based on the number of rooms and considering each room as occupied by two persons or on basis of the actual number of persons served by the tank, whichever is greater.


4.1 Septic Tank4.1.2 Inlet and Outlet The invert level of the inlet shall not be less than 5 cm

above the liquid level of the septic tank. A vented inlet baffle or sanitary tee shall be provided to

divert the incoming sewage downward. The baffle or tee shall penetrate at least 15 cm below the liquid level, but the penetration shall not be greater than that allowed for the outlets baffle or sanitary tee.

The outlet baffle or sanitary device shall extend through the scum layer above the liquid level of the tank to approximately 2.5 cm from the inside top of the tank.

The invert of the inlet pipes shall be at a level not less than 5 cm above the invert of the outlet pipe


4.1 Septic Tank

4.1.3 Tank Proportions

If two or more compartments are used, the first compartment shall have the capacity from one-half to two-thirds of the total volume of the tank.

The septic tank shall have a liquid drawing depth not less than 1.20 meters (4 feet).

The vertical distance from the liquid level to the inside top of the tank shall be at least 20 cm (8in).


4.1 Septic Tank4.1.4 Inspection Manholes Shall be provided with an inspection manhole 0.36

sq.m. (4 sq.ft.) in minimum area or by equivalent removable cover slab to provide access to the inlet and outlet devices and to the compartment of the tank for inspection and cleaning.

Septic tanks installed under concrete or block top paving shall have the required manholes accessible by extending the manhole openings to grade.


4.1 Septic Tank

4.1.5 Construction of Septic Tank

4.1.6 Location

Shall be located not less than 25 metersfrom any well, spring, cistern, or other sources of drinking water supply; not less than 1.5 m from any water service line; and not less than 3.0 meters away from water main.

Shall not be located under the building.


4.1 Septic Tank

4.1.7 Maintenance

Shall be inspected at least once a year and be cleaned when the bottom of the scum mat is within 3 inches of the bottom of the outlet device or the sludge and scum has reduced the liquid capacity by 50%.

Tanks shall not be washed or disinfected after cleaning. A small residual of sludge shall be left in the tank for seeding.


4.2 Leaching Tile Field

4.2.1 Design

A leaching tile system utilizing trenches 0.45-0.90 m wide is considered to be a leaching tile field.

A leaching tile system utilizing trenches more than 0.90 m wide is considered to be a leaching bed.


4.2 Leaching Tile Field

4.2.2 Construction

The leaching tile field or leaching bed shall be located not less than 25 meters from any well, spring, cistern, or other source of drinking water supply; not less than 3 meters from an occupied building; and not less than 1.5 meters from any lot line.


4.3 House Sewers

4.3.1 Design

Minimum size shall not be less than 100mm (4 inches) in diameter

Section 5: Public Sewerage System

5.2 Provision of Sewerage System

5.2.2 Operation of Sewage Treatment Plants

a. The sewage treatment plant shall be capable of treating the flow of sewage discharged by the community in the area.

b. The type of sewage treatment plant shall be approved by the Secretary or his duly authorized representative and the effluent from such treatment plants shall meet the standards formulated by the Department of Environment and Natural Resources.

c. The sewage treatment plant shall provide laboratory facilities for control tests and other examinations needed.

Section 5: Public Sewerage System

5.2 Provision of Sewerage System5.2.2 Operation of Sewage Treatment Plantsd. Operating data, control tests and such other

records as may be required shall be forwarded to the local health authority.

e. The local health authority shall be informed in case of breakdown or improper functioning of the treatment works.

f. Where sewage treatment plant is provided, no sewage shall be allowed to by-pass the plant.

g. The sewage treatment plant shall be managed by a registered sanitary engineer.

Section 6: Damage to Public Sewer or Sewage Disposal System

6.1 It is unlawful for any person to discharge anything which would cause damage to the public sewage disposal system, whether the system is government or privately-owned.

Effectivity

IRR of the Chapter 17 of PD 856 was approved on December 21, 1995

Date of Publication: February 22, 1996

Private Sewage Disposal Systems

Definition: (SEPTIC TANK)

A watertight covered receptacle designed and constructed to

receive the discharge of sewage from a building sewer, separate solids from the liquid, digest organic matter and store digested solids through a period of detention, and allow the clarified liquids to discharge for final disposal

SLUDGE- solid organic matter that are denser than water and settle at the bottom of the septic tank

SCUM- lighter organic material that rise to the surface of the water

EFFLUENT- liquid content of sewage

DISPOSAL PHASE- the final stage of the plumbing process; where used water and water-carried wastes are brought to various disposal outlets

Bacteria in septic tankto encourage decomposition:

Aerobic bacteria- relies on oxygen to survive

Anaerobic bacteria- can survive in places without oxygen

SEPTIC TANK

MinimumDimensions:L= 1500mmW=900mmD=1200mm

SEPTIC TANK

SINGLE CHAMBER SEPTIC TANK:

SEPTIC TANK

should show all dimensions, reinforcing, structural calculations, and such other pertinent data as needed.

DESIGN CRITERIA:

PLANS:

shall be such as to produce a clarified effluent of acceptable standards and shall provide adequate space for sludge and scum accumulations.

QUALITY OF DESIGN:

constructed of durable materials, not subject to excessive corrosion or decay, shall be watertight.

MATERIALS:

Material: cement (most common) or pre-fabricated cast iron

SEPTIC TANK

have a minimum of 2 compartments:First compartment: not less than 2/3 capacity of the total capacity of tank; not less than 2 cum liquid capacity; shall be at least 0.9 m width and 1.5 m long; Liquid depth not less than 0.6 m nor more than 1.8 m.Secondary compartment: maximum capacity of 1/3 total capacity of tank; minimum of 1 cum liquid capacity

COMPARTMENTS:

In septic tanks having over 6 cum capacity, the secondary compartment should be not less than 1.5 m in length.

with at least two (2) manholes, 508 mm in min dimension; one over inlet, other over outlet. Wherever first compartment exceeds 3.7 m in length, an additional manhole required over the baffle wall.

MANHOLES:

maintain a slope of 1:10 at the bottom of the digestion chamber to collect the sludge and make it easily accessible from the manhole

SEPTIC TANK

Inlet and Outlet pipes diameter size not less than the sewer pipe

SIZES OF PIPE INLET & OUTLET & THEIR VERTICAL LEGS:

Vertical legs of inlet and outlet pipes diameter size not less than the sewer pipe nor less than 104.6 mm.

Shall extend 101.6 mm above and at least 304.8 mm below the water surface

LENGTH AND LOCATION OF INLET & OUTLET:

Invert of the inlet pipe shall be at a level not less than 50.8 mm above the invert of the outlet pipe.

equal to the cross sectional area of the house sewer.

VENT DIAMETER:

SEPTIC TANK

Side walls shall extend 228.6 mm above liquid depth.

AIR SPACE:

Cover of septic tank shall be at least 50.8 mm above the back vent openings.

PARTITION (between compartments):

An inverted fitting equivalent in size to the tank inlet, but in no case less than 104.6 mm in diameter, shall be installed in the inlet compartment side of the baffle with the bottom of the fitting placed midway in the depth of the liquid. Wooden baffles are prohibited.

Shall be capable of supporting an earth load of not less than 14.4 kPa

STRUCTURE:

SEPTIC TANK

The capacity of septic tanks is determined by the number of bedrooms or apartment units in dwelling occupancies; by the estimated waste/sewage design flow rate for various building occupancies; or by the number of fixture units of all plumbing fixtures; whichever is greater.

CAPACITY:

The capacity of any one septic tank and its drainage system shall also be limited by the soil structure classification in its drainage field.

Should not be located underneath the house

LOCATION:

At least 15 meters from the water distribution system

SEPTIC TANK

Isometric Viewof a Typical Drainage System with Septic Tank System

Private sewage disposal system common in rural areas for structures with large adjacent open fields

DISPOSAL FIELD

No excavation for leach bed shall extend within 1.5 m of the water table.

DISTANCE FROM WATER TABLE:

WITH SEEPAGE PIT:

Filter material in the trenches shall terminate 1.5 m from pit excavation and the pipe extending from such points to the seepage pit shall be watertight.

dependent on the required septic tank capacity or estimated sewage flow rate, whichever is greater, and;the type of soil found in the excavation.

AREA:

DISPOSAL FIELD

based on the quantity of liquid waste and on the character and porosity of the surrounding soil.

CAPACITY:

Circular in shape with excavated diameter of not less than 2.2 m and to be lined with clay or concrete brick.

SIZE OF SEEPAGE PIT:

a loosely lined excavation in the ground, which receives the discharge of a septic tank; designed to permit effluent to seep through pit bottom and sides

SEEPAGE PITS

Brick lining shall have a minimum compressive strength of 17225 kPa.

STRENGTH:

served through a distribution box or shall be connected in series by means of a watertight connection. The outlet shall have a vented leg fitting extending 304.8 mm below the inlet fitting.

MULTIPLE SEEPAGE PITS:

SEEPAGE PITS

a non-watertight linedexcavation in the groundwhich receives the dischargeof a sanitary drainage system,designed to retain the organicmatter but permitting the liquidto seep through the pit bottomand sides

CEESPOOLS

Temporary expedient pending the construction of a public sewer, so long as it is established that a public sewer will be available in less than 2 years and the soil and ground water conditions are favorable;

TEMPORARY PERMITS:

As an overflow facility when installed in conjunction with an existing cesspool;

As a means of sewage disposal for limited, minor, or temporary uses.

CEESPOOLS

Outside Privy- oldest form of disposal of organic waste. Consists of a vault constructed of concrete for the collection of raw sewage and a wooden shelter

PRIVIES

When liquid wastes containing excessive amounts of grease, garbage, flammable wastes, sand, or other ingredients which may affect the operation of a private sewage disposal system, an interceptor for such waste shall be installed.

REQUIREMENTS:

Waste from interceptors may be discharged to a septic tank or other primary system or into a separate disposal system.

DISPOSAL:

COMMERCIAL/INDUSTRIAL SPECIAL LIQUID WASTE DISPOSAL

GENERAL GUIDELINES FOR PRIVATE SEWAGE DISPOSAL SYSTEMS

Location of Sewage Disposal System

MIN. HORIZONTALDISTANCE IN CLEARREQUIRED FROM

BLDGSEWER

SEEPAGEPIT OR

CESSPOOL

SEPTICTANK

1Buildings or

structures*

0.6 m1.5 m 2.4 m 2.4 m

2

Property line

Adjoining private

Property

Clear** 1.5 m 1.5 m 2.4 m

3Water supply

wells15.2 m 15.2 m 30.5 m 45.7 m

4 Streams15.2 m 15.2 m

15.2 m 30.5 m

5 Trees - 3 m - 3 m


DISPOSALFIELD

Location of Sewage Disposal System

MIN. HORIZONTALDISTANCE IN CLEARREQUIRED FROM

BLDGSEWER

DISPOSALFIELD

SEEPAGEPIT OR

CESSPOOL

SEPTICTANK

6Seepage pits or

Cesspools- 1.5 m 1.5 m 3.7 m

7 Disposal field 1.5 m 1.2 m 1.5 m

8On site domestic

Water service line0.3 m 1.5 m 1.5 m 1.5 m

9Pressure public

Water main3 m 3 m 3 m 3 m


GENERAL GUIDELINES FOR PRIVATE SEWAGE DISPOSAL SYSTEMS

Sewage Treatment Plan (STP)

An aeration system within the tank;

Some features of STP:

A submersible mixer to mix the waste;A sludge waste pump that aids in clarifying;A decanter;Blowers;A fully electronic control system, etc.

DESIGN OF GREASE TRAP



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Plumbing Design and Installation

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