(A) A certificate of operation may be suspended, revoked, or denied by the superintendent if, upon inspection, a boiler or pressure vessel is found to be unsafe to operate at the allowed safe working pressure for that boiler or pressure vessel.
(B) After inspection, an inspector may reduce the working pressure, determine necessary repairs for a boiler or pressure vessel, or declare the boiler or pressure vessel to be unsafe and stamp it with the letters XX, followed and preceded by an arrowhead. The stamping shall be adjacent to the code stamping and shall not be removed except at the direction of the superintendent. The letters XX shall be no less than five-sixteenths inch high and the arrowhead shall be no less than one-half inch long and no less than five-sixteenths inch high.
(C) If an inspector finds a crack in a lap-riveted longitudinal joint of a boiler that extends parallel to the longitudinal joint located adjacent to or between rivet holes, the boiler shall not be used or returned to use until it has been inspected and repaired as approved by the inspector and superintendent. An inspector shall not accept patching of cracks as a repair to a crack in a lap-riveted longitudinal joint of a boiler. An inspector may accept a complete new course of the original plate thickness as a repair to a crack in a lap-riveted longitudinal joint of a boiler.