UNIT – V
PART – A
1. Define plumbing.
Plumbing in a general term which indicates the practice, material and fixtures used in
the installation or maintenance of all pipings, fixtures, appliances and other
appurtenances used in connection with other public or private water supply systems as
well as sanitary or drainage systems, within or adjacent to any building or its connection
with any point of public disposal.
2. What is “Plumbing water supply”?
Plumbing water supply system is consisted of supply distribution pipes (called service
pipes), connections, domestic storage tanks, flushing storage tanks etc in a building.
3. What is plumbing sanitary or drainage system?
Plumbing sanitary or drainage system consists of water closets, urinals and other such
appliances like traps, solid waste and sewers, flushing cisterns etc in a building.
4. Name the components of water connection system.
b) Goose neck
c) Service pipe
d) Stop cock
e) Water meter.
5. Write the importance of underground storage tanks.
Underground storage tanks are necessarily required to collect water from municipal
supply lines, if the water pressure in the main is insufficient to reach the overhead tank.
The water collected in the underground tank is then pumped into the overhead tank. The
installation of pump on the municipal mains is always prohibited by the municipal
authorities, as it reduces the water pressure in the adjoining houses or buildings.
6. Give examples for metal tanks used for water storage purpose.
Metal tanks fabricated from mild steel or galvanized iron sheets have been used in the
houses over the years, as they can be easily fabricated and are light durable and easy to
install are the examples of metal tanks.
7. What are the advantages of mild steel (M.S) metal tanks?
a) easily fabricated
c) durable and
d) easy to install.
8. Explain HDPE .
HDPE is High Density Polyethylene Pipes are used in special situation. These pipes
are not brittle like other pipes and hence a hard fall at the time of loading, unloading,
handling etc. HDPE pipes upto 630mm dia can be joined with detachable joints and can
be detached at the time of shifting the pipe line from one place to another. HDPE pipes
can be joined also by welding.
9. Write the advantage of automatic pumping system.
a) It eliminates the need for overhead tanks and is ideal for existing buildings when
new overhead tank. Cannot be constructed and also for new buildings and when
the tanks placed on roof cannot generate enough pressure at upper floors.
b) The system is able to supply water at much higher pressure than it is possible
from local overhead tanks.
c) System is more reliable in such situations in hot climatic regions; the water
supplied from overhead tanks becomes too warm, while in cold regions, it may
10. What is “bib cock”?
Bib cock is a type of valve provided at the end of service pipes for with drawing
water at the consumer houses. By rotating the handle of the bib cock, the orifice opening,
through which the water passes, can be increased or decreased, thereby controlling the
outflow through the spout.
11. What is the use of ventilation in the buildings?
The ventilation is usually achieved by providing a fresh air inlet connected to the
lower-most manhole or inspection chamber. Fresh air from the atmosphere will enter
through this inlet into the manhole, and finally goes out at top through the vent pipe. The
air along with foul gases will finally escape out from the cowl provided at the top. A flap
valve is provided at the inlet of fresh air into the inspection chamber, to avoid the escape
of foul gases in the street or courtyard.
12. What are called sanitary fittings?
Plumbing is the practice, materials and fixtures used in the installation or
maintenance of all pipes in connection with both water supply and sanitary systems
within or adjucent to any building. The entire system of piping, fittings and the
appurtenances are known as plumbing system. Sanitary plumbing system includes the
pipes, fittings are the appliances used in a house plumbing system, to receive the human
excreta and sullage wastes of the house.
13. List out the various sanitary fittings.
Sanitary fittings are:
1. Water closets (WC),
3. Flushing cistern for water closets
4. Bath tubs,
5. Washing basins,
6. Kitchen sinks.
14. Write any five principles of sanitary plumbing system
a) The house sewer should be connected to the street sewer, keeping the outfall
level of the house sewer sufficiently higher than the water level of the public
sewer to avoid backflow.
b) The plumbing system should contain enough number of traps, to avoid
evolution of foul smells and the efficient functioning.
c) Laterals should be laid at sufficient slope so as to develop self-cleansing
d) The joints of the pipes should be made watertight.
e) The layout of the system should be such as to permit easy cleaning in case of
15. Define house drain sizing.
The size of pipe to be used in a house drain is determined by the number of units
drained by it. Proper diameters are: for 2 units, 1 1/2"; for 9 units, 2"; for 25 units, 2 1/2".
The size of any stack, house drain, or sewer must be, however, at least the size of the
argest branch connected to it. The minimum size of a house drain receiving the discharge
from a water closet should be 4" in diameter, and this pipe should continue full size to the
vertical stacks receiving the discharge of water closets. Even without any water closets
discharging into a system, the drainage system should have at least one 3" diameter stack
extended full size through the roof.
16. How will you size the vent pipe?
The proper size for the vent stack is determined by the total fixture units of the
soil or waste stack it serves. A branch vent is sized by the number of units connected to it
and the length of the pipe itself. No vent pipe should be less than 1 1/4" in diameter, nor
should a vent stack's diameter be less than half the diameter of the soil stack it serves.
This means that with a 4" soil stack, vents cannot be less than 2" pipe. In determining the
length of vent piping, regard length of stack and branches as being continuous.
17. Write short note on smoke test in pipes.
The smoke test requires the use of a smoke machine. All lower openings in the
system are sealed, but the roof openings are left uncapped. Smoke is then pumped into
the system until a considerable volume of it is seen issuing from the roof openings. Then
they are capped. The machine continues to force smoke into the piping until a pressure
equivalent to a rise of one inch in a water column gauge is reached. At this point, check
all connections for signs of smoke. The principal objection to the smoke test is the
possible damage it might do to interiors in the case of a line break.
Make either the peppermint or the smoke test on old piping. The peppermint test
is preferred because it can be detected in places, such as underground piping, where
smoke cannot. As these tests are usually made in the presence of a local building or
public health inspector, you should pre-test all connections before calling him in. You
should also remember that excessive pressure in either the smoke or the air test will blow
out your trap seals, defeating the entire purpose of the test. To avoid this, take care to use
only recommended pressures.
18. What are the advantages of aeration system in water treatment
• Plants are easy to operate, as the management of operation is for a maximum of
two or three hours per day.
• Extended aeration processes are often better at handling organic loading and flow
fluctuations, as there is a greater detention time for the nutrients to be assimilated
• Systems are odor free, can be installed in most locations, have a relatively small
footprint, and can be landscaped to match the surrounding area.
• Extended aeration systems have a relatively low sludge yield due to long sludge
ages, can be designed to provide nitrification, and do not require a primary
19. What are the disadvantages of aeration system in water treatment
• Extended aeration plants do not achieve denitrification or phosphorus removal
without additional unit processes.
• Flexibility is limited to adapt to changing effluent requirements resulting from
20. Explain FRP.
FRP is Fibre Glass Reinforced Plastic or composite of glass fibre, polyester resin and
fillers. These pipes possess better strength, durability, high tensile strength and are highly
21. List the different systems of plumbing.
The different systems of plumbing are as follows.
1. Two pipe system
2. One pipe system
3. Single stack system
4. Partially ventilated single stack system.
22. What are the various kinds of vent piping?
a) Main vent
b) Branch vent:
c) Fixture vent:
d) Individual trap vent:
e) Dual connection
23. What is meant by individual trap vent?
A trap may be supplied with air near its crown by the installation of a vent at the
trap itself. In this way, the possibility of a vacuum forming at this point is eliminated.
24. Write a note on branch vent in drainage piping.
Connected to the main vent, this pipe serves two or more fixture vents. It and the
fixture vent should be run to a height above the overflow level of the fixture being
served. This prevents sewage from draining through the vent line if the fixture waste
branch gets clogged.
When properly connected, vent lines will remain free and any stoppages in the
drain piping will be indicated by the backing up of waste into the fixture.
25. Write about the Single stack system
This system is having a single pipe for soil, waste and vent without any separate
ventilation pipe. It uses only one pipe, which carries night soil as well as sullage and the
same pipe is extended up to 2 m above roof level with a cowl to act as vent pipe for
removal of gases.