1. Each steam boiler having a capacity over twenty-five gallons [94.6 liters] must have a bottom blowoff connection fitted with a valve or cock connected to the lowest water space practicable with a minimum size as shown below:

Minimum Required Safety Valve Capacity in Pounds of Steam/Hour			Steam Boiler Blowoff Piping Valve Size, Inches (Min.)
Up	to	500	3/4
501	to	1,250	1
1,251	to	2,500	1 1/4
2,501	to	6,000	1 1/2
6,001	and	larger	2

2. Each hot water boiler and each steam boiler having a capacity not exceeding twenty-five gallons [94.6 liters] must have a drain valve connected to the lowest water space practicable. The minimum size of this drain valve is three-quarter inch [1.9 centimeters].

History: Effective July 1, 2020.

General Authority: NDCC 23.1-16-07

Law Implemented: NDCC 23.1-16-07