Minnesota Administrative Rules
Agency 151 - Labor and Industry Department
Chapter 5225 - BOILERS AND BOATS
BOILER SAFETY
Part 5225.4100 - SAFETY VALVES

Every high pressure or low pressure boiler must have at least one safety valve. A high pressure boiler of more than 500 square feet of water heating surface must have two or more safety valves. All safety valves must meet the requirements of Section I, IV, or VIII of the American Society of Mechanical Engineers Boiler and Pressure Vessel Code, and be so stamped, and be set no higher than the maximum allowable working pressure on the inspector's certificate for that boiler.

Every safety valve must be connected to the boiler independent of any other connections, and attached as close as possible to the boiler, without any unnecessary pipe or fitting and must stand in an upright position. No valve of any description may be placed between the required safety valve or valves and the boiler, nor on the discharge pipe between the safety valve and the point of discharge. All safety valves must discharge at a point of safety not less than seven feet from running boards, platforms, or adjacent areas. No reduction in pipe size is allowed in discharge piping from a safety valve. The discharge pipe must be of sufficient size to allow complete discharge without back pressure.

Statutory Authority: MS s 175.171; 183.42; 183.44; 183.465; 183.466; 183.54; 326B.958; 326B.964; 326B.966; 326B.982