7.2.3.1.Traps

(1) Except as provided for in Sentence (2), traps shall (a) have a trap seal depth of not less than 38 mm, (b) be so designed that failure of the seal walls will cause exterior leakage, and (c) have a water seal that does not depend on the action of moving parts. (See Note A-7.2.3.1.(1) and (3)) (2) The trap seal depth on fixtures draining to an acid waste system shall be a minimum of 50 mm. (3) Except for a floor-mounted service sink, every trap that serves a lavatory, a sink or a laundry tray shall (a) be provided with a cleanout plug located at the lowest point of the trap and of the same material as the trap, except that a cast iron trap shall be provided with a brass cleanout plug, or (b) be designed so that part of the trap can be removed for cleaning purposes. (See Note A-7.2.3.1.(1) and (3)) (4) A bell trap shall not be installed in a drainage system. (5) A drum trap shall not be installed in a drainage system. (6) Except as permitted in Sentence (7), no bottle trap shall be used in a plumbing system. (7) A bottle trap may be used on a laboratory sink or other fixture equipped with corrosion resistant fittings. (8) No running trap shall be installed in a plumbing system unless an accessible handhole is provided for cleaning of the trap, and where the trap is too small to accommodate a handhole, a cleanout shall be provided.