Minn. R. agency 151, ch. 5225, BOILER SAFETY, pt. 5225.4300
When shutoffs are used in pipe connections between a boiler and water column or between a boiler and the shutoff valves required for the gage glass they must be either outside-screw-and-yoke or lever-lifting type gate valves or stopcocks with levers permanently fastened and marked in line with their passage, or other through-flow construction to prevent stoppage by deposits of sediment. These valves must indicate by the position of the operating mechanism whether they are in open or closed position; and the valves or cocks shall be locked or sealed open. Where valves are used they must be a type with the plug held in place by a guard or gland.
The steam and water connections to a water column, including all pipe, fittings, valves, and drains must be readily accessible for internal inspection and cleaning by providing a cross or fitting with a back outlet at each right-angle turn, or by using pipe bends or fittings which will permit the passage of a rotary cleaner. The water column shall be fitted with at least a three-fourths inch pipe size valve drain with a suitable connection to a safe discharge point.
Minn. R. agency 151, ch. 5225, BOILER SAFETY, pt. 5225.4300
Statutory Authority: MS s 175.171; 183.42; 183.44; 183.465; 183.466; 183.54; 326B.958; 326B.964; 326B.966; 326B.982