ppt about envt. engg.

1. Aditi K. Shah
Roll No.: 45

2. Traps
A trap is a depressed or bent sanitary fitting
which always remains full of water (water seal).
The function of a trap is to prevent the entry of
bad smelling gases into the house. The
effectiveness depends upon the depth of water
seal, which varies from 25 to 75mm

3. Requirements of good trap:
1. It should be capable of being easily cleaned.
2. It should be easily fixed with the drain.
3. It should be of simple construction.
4. It should possess self-cleansing property.
5. It should posses adequate water seal to fulfil the purpose
of installation.
6. It should be free from any inside projection which are
likely to obstruct the passage of flow of sewage.
7. The internal and external surfaces should be of smooth
finish.

4. Types Of Traps:
a. P-trap.
b. Q-trap.
c. S-trap.

5. P- trap:
• As its name suggests, the p-trap vaguely
resembles the letter "p" when turned on its side.
• P-traps exit into the
wall behind the sink

6. S- trap:
• The "S" shape traps water so that odours from
the sewer don't come up through the drain. A
second and only slight benefit from the shape is
that it can trap heavier objects, such as
rings, that fall into the drain.

7. Q- trap:
• This trap is used in toilet under water closet. It
is almost similar to S trap and is used in upper
storey other than ground floor.

8. Vent pipe:
• The pipe installed for the purpose of ventilation is
known as vent pipe through which foul gases escape
into atmosphere.
• Without a vent pipe (stack vent), as wastewater
flows down your waste pipe, a partial vacuum would
develop at the top of the pipe which would stop the
wastewater from flowing the rest of the way down.

9. Vent pipe (fig.):

10. Rainwater pipe:
• The pipe carrying only rainwater (from the roof
tops) is called rain water pipe.
• The advantage of rainwater pipes is:
1) Prevents accumulation of water on
roof.
2) Water can be collected for
harvesting, domestic purposes like
washing, cleaning etc.

11. Rainwater pipe (fig.):

12. Anti- siphonage pipe:
• Anti- siphonage pipe means any pipe provided
in conjunction with a trap in the sanitary fitting
to prevent unsealing of the trap by siphonage or
back pressure.
• Back- siphonage causes breaking of the water
seal therefore anti-siphonage pipe is requires

13. Anti- siphonage pipe (fig.):