s4-Water Supply and Sewarage

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PLUMBING SERVICES

WATER SUPPLY, DRAINAGE ANDSANITATION



The plumbing system shall include

•the water supply and distribution pipes;

•plumbing fittings and traps;•soil, waste, vent pipes and anti-siphonage pipes;

• building drains and building sewers including their

respective connections,

• devices and appurtenances within the property lines of

the premises;

•water-treating or water-using equipment.

PLUMBING SYSTEM



WATER SUPPLY



TERMINOLOGY

Available Head—The head of water available at the point

of consideration due to main’s pressure or overhead tank

or any other source of pressure.Backflow—The flow of water or other liquids, mixtures or

substances into the distributing pipes of a potable supply

of water system from any source or sources other than its

intended source



Consumer’s Pipe—The portion of service pipe used

for supply of water and which is not the property of

the Authority

Service Pipe—Pipe that runs between the

distribution main in the street and the riser in the

case of a multi storeyed building



Water Supply Requirements for Building

Types

Water Supply for Residences

Basic requirements of water supply drainage andsanitation recommends a per capita water

consumption of 135 litres per head per day

Water requirements for domestic purposes

House hold activity Amt of water/head /day

Bathing 55

Washing clothes 20

Flushing of wc 30

Washing the house 10

Washing of utensils 10

Cooking 5

Drinking 5

Total 135



Water requirements for other buildings

House hold activity l/h/d

Factories 40

Hospitals 400

Nurses’ homes and medical quarters 135

Hostels 135

Hotels 200

Offices 45

Restaurants 70

Cinemas, concert halls and theatres 15/sSchools 45/135



There are four basic methods of

distribution of water to multi-storeyed

buildings.

a) Direct supply from mains to ablutionary

taps and kitchen WCs and urinals supplied by

overhead tanks.

b) Direct Pumping Systems

c) Hydro-Pneumatic Systems

d) Overhead Tanks Distribution

DISTRIBUTION SYSTEMS IN MULTI-STOREYED BUILDINGS



Direct Supply System

This system is adoptedwhen adequate

pressure is available

round the clock at the

topmost floor. With

limited pressure

available in most city

mains, water from direct

supply is normally not

available above two orthree floors.



Direct Pumping

•Water is pumped directly into the distribution system

without the aid of any overhead tank, except for

flushing purposes.

• The pumps are controlled by a pressure switchinstalled on the line.

•Normally a jockey pump of smaller capacity installed

which meets the demand of water during low

consumption and the main pump starts when the

demand is greater.•The start and stop operations are accomplished by a

set if pressure switches are installed directly on the

line.





• Direct pumping systems are suitable for buildings

where a certain amount of constant use of water isalways occurring.

• These buildings are all centrally air conditioned

buildings for which a constant make up supply for

air conditioning cooling towers is required .

• The system depends on a constant and reliable

supply of power. Any failure in the power system

would result in a break down in the water supply

system.

• The system eliminates the requirements ofoverhead tanks for domestic purposes (except for

flushing) and requires minimum space



Hydro-Pneumatic Systems

•variation of direct pumping

system.

•consist of a small steel tank,divided into two compartments by

a rubber membrane. One contains

water, the other air.

• A pump periodically switches onand pumps water into the wet side;

this causes the membrane to

expand, and compresses the

trapped air on the other side. The

water on the wet side is thus underpressure; it is connected to the

water supply line, which in turn

gets pressurized.





The air in the pressure tank slowly reduces

the volume due to dissolution in water and

leakages from pipe lines.

An air compressor is also necessary to feedair into the vessel so as to maintain the

required air-water ratio.

The system shall have reliable power supply

to avoid breakdown in the water supply.



•With this arrangement the same pump is able to

deliver water as required at different times of the day.

•The system consumes energy in proportion to the

work done and save considerable amount of power as

compared to the fixed speed pumps usedconventionally.

•Hydro-pneumatic system generally eliminates the

need for an over head tank and may supply water at a

much higher pressure than available from overheadtanks particularly on the upper floors, resulting in even

distribution of water at all floors



Over-head Tank Distribution

• This is the most common of the distribution systems

adopted by various type of buildings. The system

comprises pumping water to one or more overhead

tanks placed at the top most location•Water collected in the overhead tank is distributed to

the various parts of the building by a set of pipes

located generally on the terrace. Distribution is

accomplished by providing down takes to variousfixtures.





WATER AND WASTE REMOVAL



Water and Waste Removal

•Used water and other wastes are carried to the sanitary

sewer or septic tank through the waste removal system.

•These pipes are isolated from the water supply system

and must be sized for sufficient capacity, have the properslope and venting, and have provisions for cleanouts.

•The drainage system is not under pressure and

depends on gravity to carry the waste to the sewer.



Terminology

•The terms “soil pipe” and “waste pipe” are bothderived from the original two-pipe system of

sanitation where a soil pipe was connected to a WC

and a waste to an ablutionary fitting. These are also

called “discharge pipes”. •The terms “stack” relates to a vertical pipe. The

portion of which carries waste water is referred to as

the “discharge stack”, and the part which does not

carry waste is called the “ventilation stack”. • A pipe carrying waste water from a fitting or group of

fittings to the main discharge pipe is called a “branch

discharge pipe”.



Typical Drainage System

Schematic of a typical water and waste removal system.




• A vertical drain pipe that collects wastefrom one or more fixtures is called a soil

stack.

•Soil stacks that drain water closets are

called main stacks.

•Every house must have at least one main

stack, which is generally 3" in diameter.

•Each bathroom must have a main stack.

•Stacks that do not drain water closets are

called secondary stacks.

•Secondary stacks are 1-1/2" diameter.




•Fixtures are connected to the stackusing a branch main.

• All stacks extend into basement

and empty into the house drain.

• All structures must have at least

one house drain, but may have

several.

•The house drain becomes the

house sewer once it is outside thehouse. The house sewer empties

into the city sanitary sewer or

private septic system.




•Gases from the system dissipatethrough the vent stack —12" above

roof. The vent stack provides an air

inlet for the drainage system to

operate properly

• A trap is installed below each

fixture to prevent gases from

entering the house. The trap is

always filled with water. Water

closets have a built-in trap.

•Each stack requires a cleanout at

the base.



House Drain

• A house drain is the pipethat receives all waste and

water discharged by the soil

stacks and waste lines.

•This house drain is laid froma point just outside the

building foundation wall

where it connects to the

house sewer, then through

the wall, to the point where

connection with the soil

stack is made.

H T



House Trap

•Building traps provided with a

cleanout and a relief vent or

fresh air intake on the inlet side

of the trap.

•Relief vents or fresh air intake

shall be carried above grade

and shall be terminated in a

screened outlet located outside

the building.

•The size of the relief vent orfresh aid intake shall not be

less than one-half the diameter

of the drain to which the relief

vent or air intake connects.

Cl



Cleanouts

-cleanout fitting with a removable plug

It is designed to help keep clear any type

of debris that could cause any type of

stoppage in the water drain lines.

Cleanouts are usually placed at the

connection point between the sewer lines

and the drain lines where the base is

located of a vertical stack and at all

places were the pipe direction changes

at 90 degrees.



Riser Diagram

• -are used as supplementary details on working

drawings in order to show more clearly how the

plumbing system is to be installed.

•Riser diagrams of plumbing systems can be shown in

both orthographic and isometric views.•The most commonly used type of riser diagram for

plumbing is the isometric riser diagram.

•The isometric riser diagram provides a three-

dimensional representation of the plumbing system.



Typical isometric riser diagram



Riser Diagram

Typical elevation riser diagram



Plumbing Plans

•plan view that shows the complete plumbing system.• The plumbing plan shows the location, size, and type of

all plumbing equipment.

•The plumbing plan should include:

• Waste lines and vent stacks.

• Drain and plumbing fixture locations.

• Size and type of pipe to be used.

• A plumbing fixture schedule.

• Symbols Legend.• General notes.

Pl bi S b l



Plumbing Symbols



Waste Pipe Connections

Appliance Waste Size

Sinks 40 mm

Shower Trays 40 mm

Baths 40 mmWash Basins 32 mm

Bidets 32 mm

Bowl Urinals 32 mm

Drinking Fountains 32 mm

W.C. Pan and all Soil Appliances 100 mm



A trap is a fitting or part of an appliance designed to retain a body of

water thus preventing the passage of foul air.

There are many different types of traps:

“S” traps - Vertical outlet

“P” traps - Horizontal outlet

“Bottle” traps - Horizontal outlet

“Running” traps - Horizontal outlet

Traps





•The trap most commonly used with

plumbing fixtures is the P-trap. The P-trap gets its name because of its

general shape-that of the letter P.

•Traps are required because they

prevent sewer gases from entering abuilding and causing serious illness or

death.

•The term trap seal refers to the water

being held in the bent portion of afixture trap. The trap seal forms a seal

against the passage of sewer gases

through the trap and into the building.



Examples of P-Traps



Trap Seals

The depth of the trap

depends upon the

circumstances and the

usage of the pipe, butin general pipes of less

than 50mm internal

bore (e.g. baths, wash

hand basins, sinks etc)

would have a trap witha seal of not less than

75mm.



Loss of Trap Seals

The most likely ways for traps to loose their seal are:

Leakage: This will allow water in the trap to empty onto the floor and is

consequently soon noticed and repaired

Siphonage: This may be either self siphonage or induced siphonage

Compression: When water is discharged from an application at a higher level the

air in the vertical pipe may become compressed sufficiently to “blow” out the seal inthe lower appliance

Capillary Attraction: If a piece of absorbent material is caught in the outlet of the

trap with one end dipping in the water and the other end hanging over the outlet, the

water may be drawn out by capillary action through the metal

Wavering Out: This is caused by gusts of wind passing over the top of the vent pipeand is often noticed in a WC trap on a windy day.

Evaporation: If the appliance is not in use for a long period of time the water in the

trap will evaporate

Momentum: This is caused by the sudden discharge of water into the trap



Loss of Trap Seals











Vents



•To prevent the siphonage of a trap

seal in fixture traps and allow gravity

flow of drainage, atmospheric air is letfrom outside the building into the

piping system to the outlet (or

discharge) end of the trap.

•The air is supplied through pipescalled vents. This air provides

pressure on the outlet end of the seal

equal to pressure on the inlet end.

•Since the air supplied by the vent to

the outlet end provides a pressure

equal to that at the inlet end of the trap,

the trap seal cannot escape through

siphonage.

Vents



• All vent systems should be

provided with a main vent or vent

stack and a main soil and waste

vent. A “main vent” may be defined

as the principal artery of the

venting system, and

vent branches may be connectedto the main vent and run

undiminished in size as directly as

possible from the building drain to

the open air above the roof.



A common vent vents

two traps to a single

vent pipe.

The unit vent can be

used when a pair oflavatories are installed

side by side, as well as

when they are hung

back to back on eitherside of a partition



Two Pipe System



One Pipe System

• This system was first used in the USA but it was some time

before it was accepted in this country

• Soil and waste fitting discharges are carried by one main soiland waste pipe connected directly to the drain

• Every trap in the system must be ventilated with a pipe not less

than 32mm in diameter

• To prevent air being compressed at the bottom of the mainssoil and waste stack and possible disturbance of the water

seals of the traps on the lowest sanitary fittings, and additional

vent or air relief pipe is sometimes required

• The top of the vent stack may be either carried up

independently from the main soil stack or connected to themain soil and waste stack above the highest fitting

• It is particularly suitable for apartments, offices, hotels, etc

where sanitary fittings are grouped above each other on

successive floors



One Pipe System



The single stack system depends for its performance in retaining

trap seals.

To prevent compression of the air at the base of the stack, the bend

at the foot of the stack must be a slow radius bend

This lowest connection to the discharge stack must be a minimum

distance of 450mm above the invert of the drainAll fittings must be grouped closely to the main stack so that

branch pipes are as short as possible

Single Stack System

The undesirable air pressure fluctuations in drainage pipework can, in a

certain range of circumstances, be eliminated by the observation of

simple rules without the necessity for trap ventilating pipes.



Single Stack System





Access points should be sited:

(a) At a bend or change indirection

(b) At a junction, unless each run can be cleared from an

access point. (c) On or near the head of each drain run.

(d) On long runs

(e) At a change of pipe size.

Documents

s4-Water Supply and Sewarage