HYDROSTATIC TEST PROCEDURE.pdf

HYDROSTATIC TEST PROCEDURE

1. SCOPE This procedure establishes the steps to be followed for conducting the Hydrostatic test in pressure vessels constructed in accordance with the rules of the ASME Boiler and Pressure Vessel Code Section VIII Division 1. 2. REFERENCES ASME Code Section VIII Division 1 UG-99 3. RESPONSIBILITIES The QC Chief is responsible for assure the compliance with this procedure in all items constructed in accordance with the ASME Code. 4. PROCEDURE Pressure Gages All pressure gages used in the Hydrostatic test shall be calibrated before the test using a calibrated dead weigh tester. At least one pressure gauges shall be used during the test. Gauges shall have a range of about double the intended maximum test pressure but not less than one and one half (1-1/2) nor more than four (4) times the test pressure shall be used for the test. Hydrostatic head on the gage shall be considered depending on the location of the gage. The gauge must be readily visible to the pressure test operator so he is able to monitor the increase of pressure in the vessel and avoid over pressuring the vessel during the test. Item Preparation for Testing The hydrostatic test will be conducted when all fabrication has been complete. The item shall be supported properly and the metal temperature shall not exceed of 120 °F. The water and vessel temperature shall be maintained at least 30°F above the MDMT of the vessel. The test pressure shall not be applied until the vessel and the water are at about the same temperature. All nozzles shall be plugged with the appropriate blind or plugs that prevent the leakage during the test, the nozzle located at the highest point shall be used for venting the item and one of the pressure gages shall be connected directly to the item being tested. Testing The pressure shall be increased gradually up to the hydrostatic test pressure indicated on the drawings, when the hydrostatic test pressure is obtained, it shall be maintained during the time required by the contract or until the Authorized Inspector witnesses the hydrostatic test at test pressure.

HYDROSTATIC TEST PROCEDURE

Inspection The pressure shall be reduced to the following pressure: 

The test pressure divided by 1.3

At this pressure a close inspection shall be done in all welded joints and high stressed parts. If the hydrostatic test results are acceptable, that is: no leaks in the pressure boundary of the vessel nor its temporary mechanical fittings, the QC Inspector shall record the test results in the Pressure Test Report. If any defect is found during the test, it shall be repaired in accordance with the Code and the item shall be retested in accordance with this procedure.