Environmental Engineering –I
By Prof S S JAHAGIRDAR
Components of Distribution
• Purpose of Valves
1. The primary purpose of valves is to
allow for isolation of mains or
sections of main within the network.
2. Another important function of
valves is to control flow or pressure.
1. Sluice or Gate Valve
• Also known as shut off valves or
stop valves or isolation valves.
• Used to shut of the supplies wherever
• Useful in dividing water mains in
3. Reflux Valve
• Also known as Check valve or nonreturn valve.
• Allows water to flow in only one
• They are provided next to pumps to
avoid back flow of water after
shutting off the pump.
• Back flow of water may damage the
• Pivoted Flat disc is provided, which
returns to its original position in
case of reverse flow
4. Pressure Relief Valve
• Also known as Automatic cutoff or
• Located at points where pressure is
• When pressure increases preset
value, the valve operates
automatically and pressure is
5. Altitude Valves
• Provides automatic filling of elevated
tanks or reservoirs.
• When the altitude control senses a
drop in level below the predetermined
set point, the valve opens to fill tank.
When the level again reaches the set
point, the valve will close.
• These are provided to the pipes
which supply water to ESRs or stand
• There are two types
- Single acting and
- Double acting
• Single acting : - flow in one direction
only - from the pump side to the tank.
A separate discharge line or by-pass
arrangement is used for removing the
storage water from the tank.
• Double Acting:- an altitude valve
which allows flow from the pump to
the tank and also allows reserve flow
from the tank back through the valve
to the distribution system.
6. Scour Valves
• Also known as blow off or wash out
• Located at dead end in dead end
• Provided to remove sand and silt
deposited in the pipe line.
• Operated manually.
ASSIGNMENT 4 TE –(A)
1. Find length of equivalent pipe with
equivalent diameter 0.5 m if three
pipes are connected in
a) Series and
2. Compute distribution of flows in the
pipe network shown below by using
Hardy Cross method. Take two trials
Use hf = kQ2
3. Compute distribution of flow in the
network shown below by using Hardy
Cross method. Take two trials.
Use hf = kQ1.85
1. Radial system is reverse of ______
system. (dead end/grid iron/circular/ all of
2. To increase the discharge pipes are
provided in _____. (series/ parallel/ series
or parallel/ cant say).
3. Reflux valve are also known as _____
valves. (shut off/check/cut off/ air relief).
4. Check valve is also known as _____.
(reflux valve/non return valve/ both/none of
5. Summits are the points of ____ pressure.
(high/ low/ equal/none of these).
6. Match the pairs
Located at high pressure points
Air relief valve
Used to shutoff the supplies
To provide exit for accumulated
Allows water to flow in one
7. In pressure supply mains, water hammer
pressure is reduced by providing ______.
(sluice valve/air valve/pressure relief valve/
none of these).
8. In equation hf = k.Qn the value of ‘n’ for
Hazen Williams formula is _________.
9.Reflux valve is also known as _______.
10. Washout valves are provided at _______
points in the mains. (lowest/ highest/
summit/ all of above).
Q1. Give requirements of a good
distribution system. (May 2012, Dec
2010, 5 marks).
Q2. Explain grid iron system of water
distribution with neat sketch (May
2012, 5 marks).
Q3. Draw neat sketch of air relief valve
and name its parts (Dec 2011, Dec
2009, 5 marks)
Q4. Explain grid iron system of water
distribution with neat sketch and mention
its advantages (Dec 2011, Dec 2009, 5
Q5. Explain Hardy-Cross method of
analysis of pipe network (Dec 2011, Dec
2010, 9 marks).
Q6. Draw neat sketch of non return or
reflux valve and name its parts (May
2011, Dec 2010, 5 marks).
Q7. Explain circular system of water
distribution with neat sketch (May 2011, 8
Q8. Explain Dead end system of water
distribution with neat sketch (Dec 2010, 4
Q9. Explain equivalent pipe method of
analysis of pipe network of a distribution
system (Dec 2009, 9 marks).