Except as hereinafter provided, the size of indirect waste
piping shall be in accordance with other sections of this code applicable to drainage and vent
piping. No vent
from indirect waste
piping shall combine with a sewer-connected vent
, but shall extend separately to the outside air. Indirect waste pipes
exceeding 5 feet (1524 mm), but less than 15 feet (4572 mm) in length shall be directly trapped, but such traps
need not be vented.
Indirect waste pipes less than 15 feet (4572 mm) in length shall be not less than the diameter of the drain outlet or tailpiece of the fixture, appliance, or equipment served, and in no case less than 1/2 of an inch (15 mm). Angles and changes of direction in such indirect waste pipes shall be provided with cleanouts to permit flushing and cleaning.