Section SPS 341.31 - Boiler blowoff equipment(1) PRESSURE-TEMPERATURE LIMITS. The blowdown from a boiler that enters a sewer system or blowdown which is considered a hazard to life or property shall pass through some form of blowoff equipment that will reduce pressure and temperature as specified in pars. (a) and (b). (a) The temperature of the water leaving the blowoff equipment may not exceed 160°F.(b) The pressure of the blowdown leaving the blowoff equipment may not exceed 5 psig.(2) PIPING AND FITTINGS. The blowoff piping and fittings between the boiler and the blowoff tank shall comply with ASME B31.1 or the code in effect at the time of construction.(3) TANKS AND SEPARATORS. The blowoff tank or separator shall be designed in accordance with s. SPS 341.42 or the code in effect at the time of construction for a maximum allowable working pressure of at least 50 psig.(4) GENERAL REQUIREMENTS. All blowoff equipment, except centrifugal blowdown separators, shall be fitted with openings to facilitate cleaning and inspection and shall have all of the following:(a) A pressure gage graduated from 0-50 psi.(b) A thermometer well located near the water outlet connection and in contact with the retained water in the tank.(c) A gage glass at least one-half inch in diameter with the lower connection to the glass at a point about 6 inches below the water line and the upper connection at a point about 6 inches above the water line.(d) A drain connection of at least 2-inch standard pipe size.(e) Connections designed so that freezing will not close the inlet, the outlet or the vent.(5) VENT PIPING. All blowoff equipment shall have vent piping, full size, piped to the outside atmosphere and discharged to a safe location.Wis. Admin. Code Department of Safety and Professional Services SPS 341.31
Cr. Register, February, 1988, No. 386, eff. 3-1-88; am. (4) (d) and (e), r. (4) (f), cr. (5), Register, December, 1992, No. 444, eff. 1-1-93; am. (2), (3), (4) (a), Register, June, 1996, No. 486, eff. 7-1-96; am. (2), Register, February, 2000, No. 530, eff. 3-1-00; CR 05-025: am. (1) (a) Register October 2005 No. 598, eff. 11-1-05; correction in (3) made under s. 13.92(4) (b) 7, Stats., Register December 2011 No. 672; CR 11-047: am. (1) (b), (2), (4) (intro.) to (d) Register May 2012 No. 677, eff. 6-1-12. Blowoff equipment designed in accordance with the boiler blowoff equipment rules issued by the National Board of Boiler and Pressure Vessel Inspectors will meet the requirements of this section. Other methods of designing blowoff equipment may be used if approved by the Department.