(1) The maximum allowable working pressure of a boiler or pressure vessel carrying the ASME code symbol shall be determined by the applicable sections of the code under which it was constructed and stamped.
(2) The maximum allowable working pressure of a boiler or pressure vessel which does not carry the ASME code symbol shall be computed in accordance with the American Petroleum Institute 579/ASME FFS-1 (Fitness for Service) evaluation as adopted by the department and the regulations adopted in accordance with KRS 236.030.
(3) This chapter shall not be construed as in any way preventing the use or sale of a boiler referred to in this section, provided it has been made to conform to the rules and regulations of the commissioner governing existing installations; and provided, further, it has not been found upon inspection to be in an unsafe condition.