QUESTION 7
(a)  Trade waste must be cooled before discharging to a drain or sewer. In relation to this
statement answer the following questions.
 (i) A cooling tank must be a specific size. State the factor that determines this size.
 (ii) Draw a side elevation of a typical cooling pit. [Cooling tank in ground].
(4 marks)

(b)  A petrol trap is one type of special purpose interceptor trap. State what hazard the
interceptor trap prevents and how it prevents it.
 
 
 
 
(2 marks)
(c) State when a sewage pump is required on a foul water drainage system.
 
(1 mark)
(d)  State where the non-return valve on the outlet of a sewage pump system should be
installed in relation to the isolating valve.
 
(1 mark)
Total 8 marks

Linkback: https://www.plumbers.nz/drainlaying-exam-november-2007/25/question-7/231/

c) State when a sewage pump is required on a foul water drainage system.
  when you can not gravitate it to the conection
(1 mark)
(d)  State where the non-return valve on the outlet of a sewage pump system should be
installed in relation to the isolating valve.
 
(1 mark) depending on the location of pump

on the downstream side of the valve
Total 8 marks