Minnesota Administrative Rules
Agency 151 - Labor and Industry Department
Chapter 5225 - BOILERS AND BOATS
BOILER SAFETY
Part 5225.4500 - VALVES AND FITTINGS

Valves and pipe fittings must conform to the American Society of Mechanical Engineers Boiler and Pressure Vessel Code which adopts American National Standards Institute standards for the maximum allowable working pressure. Fusion welded joints are permitted if the welding procedure and operator are qualified as required in Section IX of the American Society of Mechanical Engineers Boiler and Pressure Vessel Code.

All valves and fittings on all feedwater piping from the boiler up to and including the first stop valve and the check valve must be equal at least to the requirements of the standard accepted by Section I of the American Society of Mechanical Engineers Boiler and Pressure Vessel Code for pressure 1.25 times the maximum allowable working pressure of the boiler.

All valves and fittings for feedwater piping between the required check valve and the globe or regulating valve, and including any bypass piping up to and including the shutoff valves in the bypass, must be equal at least to the saturated requirements set out in Section I of the American Society of Mechanical Engineers Boiler and Pressure Vessel Code. The valves and fittings must have a pressure rating at least equal to the expected operating pressure required to feed the boiler for a saturated steam temperature corresponding to the minimum set pressure of any safety valve on the boiler drum or for the actual temperature of the water, whichever is greater.

Valves and fittings made of any material permitted by I of the American Society of Mechanical Engineers Boiler and Pressure Vessel Code for pressure ratings of 125 pounds or more and marked as required by the code may take up to 20 percent reduction in pressure rating when used for feed line and blowoff service.

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