46 CFR 52.01-55: -55 Maximum allowable working pressure.

(a) The piping system, machinery, and appurtenances must meet the requirements of this subchapter for the boiler maximum allowable working pressure. Only the Commandant may grant an increase in pressure.

(b) When an existing boiler is replaced by a new boiler designed to operate at pressures in excess of the pressure indicated on the certificate of inspection for the previous boiler, an analysis of the complete system must be made, including machinery and piping, to insure its compatibility with the increased steam pressure. The maximum allowable working pressure on the certificate of inspection must be based on the results of this analysis.