- Traps: The depression or bend provided in a drainage
system, which is always full of water and prevents the
entery of foul gases into the atmosphere is termed as a
trap. The water inside the trap is called seal. Traps are
made of glazed earthenware, vetereous, porceline, cast
iron, and PVC or hi-density polythelens. For detail section
of this see figure 10
Figure 11.10: Different types of traps sections