Observation

Most candidates were able to:
-           sketch the a double-bowl kitchen sink correctly;
-           state three functional requirements of an inspection chamber.
However, few of them failed to state the function of a ball valve and over flow pipe.
The expected response to question 4 is as given below:

4 (a)     One function each of the following in a water- closet cistern:
(i)       Ball valve;
Controls the water supply to a cistern.  As water is drawn from the cistern, the ball
float falls, opens the valve to let water in and as the float rises it closes the valve.
(ii)     Over-flow pipe;
Is connected to a cistern above the water line to discharge the excess water to a place where it will give obvious warning of an overflow and of the valve failure to control the water supply.      

                                                                                      
 (b)

Double bowl sink

 (c)       Three  functional requirements of an Inspection Chamber:
An inspection chamber must be:

• able to withstand all loads to which it may be subjected;
• able to exclude sub-soil water;
• must be water-tight;
• should allow easy access to the drain for inspection, testing and cleansing.