Section 8 AAC 80.110 - Safety, safety relief, or relief valves(a) When two or more boilers operating at different pressures and safety valve settings are interconnected, the lower-pressure boiler or interconnected piping must be equipped with safety valves of sufficient capacity to prevent overpressure.(b) If in-service safety relief valve testing is impractical because a pressure vessel contains liquids or gases which are hazardous or costly, the testing may be performed at intervals not to exceed five years.(c) An operator with a verified testing and inspection program, and certified under the standards of Pressure Vessel Inspection Code: In-service Inspection, Rating, Repair, and Alteration (API 510), as published by the American Petroleum Institute and adopted by reference in 8 AAC 80.010, may perform testing at intervals consistent with that standard.Eff. 6/21/84, Register 90; am 4/24/2020, Register 234, April 2020