.10 Heating Boiler — Existing Installation: Maximum Allowable Working Pressure

A. The maximum allowable working pressure on a standard boiler may not exceed the pressure stamped or cast by the manufacturer on:

(1) The boiler; or

(2) A plate secured to the boiler.

B. The maximum allowable working pressure on:

(1) The shell of a nonstandard riveted heating boiler shall be determined in accordance with Regulation .22 of this chapter, except that the maximum allowable working pressure on a:

(a) Steam heating boiler may not exceed 15 PSIG; and

(b) Hot water boiler may not exceed:

(i) 160 PSIG, or

(ii) 250F.

(2) A nonstandard steel or wrought iron heating boiler of welded construction:

(a) May not exceed 15 PSIG for steam; and

(b) For service other than steam, shall be calculated in accordance with the ASME Code, Section IV.

(3) A nonstandard boiler composed principally of cast iron, or having a cast iron shell or heads and steel or wrought iron tubes, may not exceed:

(a) 15 PSIG for steam service; and

(b) 30 PSIG for hot water service.