(1) The maximum allowable pressure of a boiler carrying the ASME code symbol or of a pressure vessel carrying the ASME or API-ASME code symbol shall be determined by the applicable sections of the code under which it was constructed and stamped.
(2) The maximum allowable pressure of a boiler or pressure vessel which does not carry the ASME or the API-ASME code symbol shall be computed in accordance with generally accepted nationwide engineering standards as required by the board.
(3) This chapter shall not be construed as in any way preventing the use, sale or reinstallation of a boiler or pressure vessel referred to in subsections (1) and (2), provided it has been made to conform to the rules and regulations of the board governing existing installations and provided, further, it has been found upon inspection to be in a safe condition and that an inspection certificate can be issued.