Western Australian Consolidated Regulations Western Australian Consolidated Regulations (1) The main drain
shall be ventilated at its upper end by a pipe ventilator erected vertically
and such ventilator may be a soil or combined waste soil vent pipe.
(2) If the drain is
provided with an interceptor trap there shall be in addition a ventilator pipe
connected to the interceptor trap shaft, and in such cases there shall,
wherever practicable, be a difference in height of not less than six feet
between the tops of the vents at the upper and lower end of the drain
respectively.
(3) A ventilator pipe
shall also be provided on the sewer side of the interceptor trap.