N.D. Cent. Code § 4.1-37-07
Bulk storage containers constructed according to the American society of mechanical engineers code, and all nurse tanks, must be equipped with pressure relief valves constructed according to the American society of mechanical engineers code and capacity certified by the national board of boiler and pressure vessel inspectors. A pressure relief valve using nonmetallic seats must be replaced every five years with a new valve meeting the standards specified in this section. A pressure relief valve using metallic seats must be tested, and repaired if deemed necessary, every five years in lieu of replacement. Repairs deemed necessary must be made by the valve manufacturer or by a safety valve repair organization having a valid "VR" certificate of authorization for the repairs from the national board of boiler and pressure vessel inspectors.
N.D.C.C. § 4.1-37-07