Abstract: The hydraulic test is the final quality inspection method usually used after the completion of the manufacture or repair of the pressure vessel in engineering. Although the test pressure is specified in the pressure vessel regulation standard, the pressure value of the hydrostatic test pressure when repairing the pressure vessel in-service is not specified as clearly as the pressure value labeled at the time of initial manufacture. Thus, deviation is likely to occur, which may affect the accuracy and safety of the hydrostatic test. This paper discusses the value of the hydrostatic test pressure in repairing a floating head exchanger. It obtains the determination principles of hydrostatic test pressure value in repairing the pressure vessel in-service. The obtained principles are to determine the test pressure value before the first periodic inspection according to the record drawings and to determine the value within the inspection period after the periodic inspection according to the Periodic Inspection Report.

Key words: heat exchanger, repair, hydrostatic test, test pressure