34 Pa. Code § 3a.141 – Riveted boilers.

(a) The ASME Code governs the determination of the maximum allowable working pressure on the shell of a riveted heating boiler.
(b) The maximum allowable working pressure of a steam heating boiler may not exceed 15 psig.
(c) The maximum allowable working pressure of a hot water boiler may not exceed 160 psig at a temperature not exceeding 250°F.

This section cited in 34 Pa. Code § 3a.3 (relating to scope).