When two or more boilers are connected to a common steam main, the steam connection from each boiler having a manhole opening must be fitted with two stop valves having an ample free-blow drain between them. The stop valves installed on high pressure steam boilers must consist of either one automatic nonreturn valve, set next to the boiler and a second valve of the outside-screw-and-yoke type; or two valves of the outside-screw-and-yoke type. The free blow drain must ensure complete removal of all condensate and steam from between the two stop valves.
MS s 175.171; 183.42; 183.44; 183.465; 183.466; 183.54; 326B.958; 326B.964; 326B.966; 326B.982
13 SR 1917; 19 SR 591; L 2007 c 140 art 9 s 27; art 13 s 4
February 19, 2009
Official Publication of the State of Minnesota
Revisor of Statutes