Section PSC 135.187 - Vaults: sealing, venting, and ventilation addition [49 CFR 192.187]After 49 CFR 192.187(a)(3), insert:
(4w) The outside end of the ducts shall be equipped with a suitable weatherproof fitting or vent-head designed to prevent foreign matter from entering or obstructing the duct. The effective area of the openings in such fittings or vent-heads shall be at least equal to the cross-sectional area of a 4-inch duct. The horizontal section of the ducts shall be as short as practical and shall be pitched to prevent the accumulation of liquids in the line. The number of bends and offsets shall be reduced to a minimum and provisions shall be incorporated to facilitate the periodic cleaning of the ducts.Wis. Admin. Code Public Service Commission PSC 135.187
CR Register, October, 1999, No. 526, eff. 11-1-99.