1. (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.
2. (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.
3. (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)

Authority: AS 18.60.180