WAC 51-56-0900   Chapter 9 -- Vents.  


903.1.2 ABS and PVC DWV piping installations shall be installed in accordance with applicable standards in Table 14-1. Except for individual single family dwelling units, materials exposed within ducts or plenums shall have a flame-spread index of not more than 25 and a smoke developed index of not more than 50, when tested in accordance with the Test for Surface-Burning Characteristics of the Building Materials (see the Building Code standards based on ASTM E-84 and ANSI/UL 723).


908.2.1 Where Permitted. Water closets, bathtubs, showers, bidets, and floor drains within one or two bathroom groups located on the same floor level and for private use shall be permitted to be vented by a wet vent. The wet vent shall be considered the vent for the fixtures and shall extend from the connection of the dry vent along the direction of the flow in the drain pipe to the most downstream fixture drain or trap arm connection to the horizontal branch drain. Each wet-vented fixture drain or trap arm shall connect independently to the wet-vented horizontal branch drain. Each individual fixture drain or trap arm shall connect horizontally to the wet-vented horizontal branch drain or shall be provided with a dry vent. The trap to vent distance shall be in accordance with Table 10-1. Only the fixtures within the bathroom groups shall connect to the wet-vented horizontal branch drain. The water closet fixture drain or trap arm connection to the wet vent shall be downstream of any fixture drain or trap arm connections. Any additional fixtures shall discharge downstream of the wet-vent system and be conventionally vented.



[Statutory Authority: RCW 19.27.074, 19.27.031 and chapters 19.27 and 34.05 RCW. 10-03-101, § 51-56-0900, filed 1/20/10, effective 7/1/10. Statutory Authority: RCW 19.27.190, 19.27.020 and chapters 19.27 and 34.05 RCW. 07-01-094, § 51-56-0900, filed 12/19/06, effective 7/1/07. Statutory Authority: RCW 19.27.031, 19.27.074. 02-01-114, § 51-56-0900, filed 12/18/01, effective 7/1/02.]