WAC 51-13-502   Statewide radon requirements.  


     502.1 Crawlspaces:


     502.1.1 General: All crawlspaces shall comply with the requirements of this section.


     502.1.2 Ventilation: All crawlspaces shall be ventilated as specified in section 1203.3 of the International Building Code (chapter 51-50 WAC).


     If the installed ventilation in a crawlspace is less than one square foot for each three hundred square feet of crawlspace area, or if the crawlspace vents are equipped with operable louvers, a radon vent shall be installed to originate from a point between the ground cover and soil. The radon vent shall be installed in accordance with sections 503.2.6 and 503.2.7.


     502.1.3 Crawlspace Plenum Systems: In crawlspace plenum systems used for providing supply air for an HVAC system, aggregate, a permanently sealed soil gas retarder membrane and a radon vent pipe shall be installed in accordance with section 503.2. Crawlspaces shall not be used for return air plenums.


     In addition, an operable radon vent fan shall be installed. The fan shall be located as specified in section503.2.7 . The fan shall be capable of providing at least one hundred cfm at one inch water column static pressure. The fan shall be controlled by a readily accessible manual switch. The switch shall be labeled "RADON VENT FAN."



[Statutory Authority: RCW 19.27.190, 19.27.020, and chapters 19.27 and 34.05 RCW. 04-07-192, § 51-13-502, filed 3/24/04, effective 7/1/04. Statutory Authority: RCW 19.27.190 and 19.27.020. 98-02-047, § 51-13-502, filed 1/5/98, effective 7/1/98. Statutory Authority: RCW 19.27.190. 95-01-128, § 51-13-502, filed 12/21/94, effective 6/30/95. Statutory Authority: RCW 19.27.190(2) and 1992 c 132. 93-02-056, § 51-13-502, filed 1/6/93, effective 7/1/93. Statutory Authority: RCW 19.27.190. 91-12-045, § 51-13-502, filed 6/5/91, effective 7/1/91; 91-01-102, § 51-13-502, filed 12/18/90, effective 7/1/91.]