605.1 General. Heating and air-conditioning systems shall be provided with approved air filters. Filters shall be installed such that all return air, outdoor air and makeup air is filtered upstream from any heat exchanger or coil. Filters shall be installed in an approved convenient location. Liquid adhesive coatings used on filters shall have a flash point not lower than 325°F (163°C).
EXCEPTION: | Cooling coils that are designed, controlled and operated to provide sensible cooling only do not require filtration at the terminal device. |
605.4 Particulate matter removal. Particulate matter filters or air cleaners having a minimum efficiency reporting value (MERV) of not less than 6 for ducted air handlers and not less than 4 for ductless mini-split systems shall be provided upstream of all cooling coils or other devices with wetted surfaces through which air is supplied to an occupiable space.
[Statutory Authority: RCW
19.27.031 and
19.27.074. WSR 20-03-041, § 51-52-0605, filed 1/8/20, effective 7/1/20; WSR 16-01-148, § 51-52-0605, filed 12/21/15, effective 7/1/16. Statutory Authority: RCW
19.27.031,
19.27.074 and chapters
19.27 and
34.05 RCW. WSR 13-04-053, § 51-52-0605, filed 2/1/13, effective 7/1/13.]