Nonstandard Cast-Iron Boilers

Nonstandard Cast-Iron Boilers 1. The maximum allowable working pressure of a nonstandard boiler composed principally of cast-iron shall not exceed 15 psig for steam service or 30 psig for hot-water service. 2. The maximum allowable working pressure of a nonstandard boiler having cast-iron shell or heads and steel or wrought iron tubes shall not exceed 15 psig for steam service or 30 psig for hot-water service.