Observation

Most candidates were able to:
- list three methods of water treatment:
- sketch a pitcher tee and label its inlet and outlet

However, some of them were unable describe how a trap may become unsealed through momentum and compression.

The required responses to question 5 (a) is given below.

5.(a)     Description of how a trap may become unsealed through the following:
(i)         momentum this is caused by the sudden discharge of water into the trap. The force of the water may be sufficient to unseal trap. The discharge of a pail full of water into a water closet (WC) is a typical example
(ii)   Compression- when the water is discharged from the higher fitting, the air in the
vertical pipe may become compressed sufficiently to blow out the seal in lower fitting.