Vent piping shall be permitted to be
omitted on an interceptor where such interceptor acts as a
primary settling tank and discharges through a horizontal
indirect waste pipe into a secondary interceptor. The second
interceptor shall be properly trapped and vented.
Traps serving
sinks that are part of the equipment of bars, soda fountains,
and counters need not be vented where the location and
construction of such bars, soda fountains, and counters is
such as to make it impossible to do so. Where such conditions
exist, said sinks shall discharge by means of approved
indirect waste pipes into a floor sink or other approved type
of receptor.