Std_Spec_505-2_Hydrostatic_Pressure_Tests.pdf

AMC-505-2

APRIL 1988

NATIONAL OCEANIC AND ATMOSPHERIC ADMINISTRATION (NOAA)

ATLANTIC MARINE CENTER

STANDARD SPECIFICATION AMC-505-2

HYDROSTATIC PRESSURE TESTS

1. SCOPE. This specification contains the general requirements for performing hydrostatic pressure tests on pressure vessels and piping systems of NOAA ships.

2. REFERENCES.

None

3. REQUIREMENTS.

3.1 Prior to conducting a hydrostatic pressure test, meet with the COTR or other designated NOAA representative and discuss preparations, precautions, and procedures to be followed during the test.

3.2 The test pressure will normally be specified in the detail specification or other procurement document which requires the test. In the event the test pressure is not specified, the test pressure shall be 125 percent of the maximum allowable working pressure of the pressure vessel or system being tested.

3.3 Isolate, disconnect, and blank-off piping, equipment and

other components to avoid contaminating or subjecting them to the test pressure. Isolation shall be by blank flanges or similar means. Valves may be used if suitable for the required test pressure. After completing the test, return the systems, piping and other components to the as-found condition.

3.4 Remove relief valves from the pressure vessel or piping

system prior to the test. Test each relief valve for proper operation and set pressure. Reset to the pressure specified in the detail specification or other procurement document. If the pressure is not specified, reset the relief valves to a pressure equal to 105 percent of the system's or pressure vessel's maximum operating pressure. Install a new seal and metal tag on each relief valve. The tag shall be stamped with the test date and pressure setting. After completing the hydrostatic pressure tests, reinstall the relief valves.

3.5 When testing pressure vessels or piping designed for air or vapor service, provide additional temporary support as needed to support the additional weight of the water during the test.

3.6 Potable water shall be used as the test medium to test

piping and pressure vessels connected to the ship's potable water system. Fresh water shall be used as the test medium for all other pressure vessel and piping system tests. When filling the system or pressure vessel, insure that all air has been vented and that all air pockets have been eliminated before applying the test pressure.

3.7 When testing new welds or flanged joints, do not insulate, paint or otherwise cover the welds or joints until the test has been accepted by the COTR or other designated NOAA representative.

3.8 Test equipment shall contain the following:

3.8.1 A self-actuated and resetting relief valve set at a

pressure no greater than 110 percent of the test pressure.

3.8.2 A master pressure gage having a low range of 0 and a

high range which equals 125-200 percent of the test pressure.

The largest graduation of the master pressure gage shall be no more than 2 percent of the test pressure. The gage shall have been calibrated within the past 12 months and have a label attached which identifies the calibration date and facility. The gage shall be mounted where it can be easily seen by the pump operator and the COTR.

3.8.3 A water pump capable of slowly applying the required

pressure.

3.8.4 An isolation valve located between the pump and the

master pressure gage to allow the pump to be isolated while the gage indicates the pressure in the pressure vessel or system.

3.9 Hold the test pressure for 10 minutes. Then hold the

pressure an additional time as needed by the COTR to conduct an inspection for leaks and excessive stress.

3.10 After the hydrostatic test has been accepted, pump and

dispose of the water used for the test. The Contractor may drain the water to the ship's bilges only if the water will be subsequently pumped from the bilges and disposed of by the Contractor.

3.11 Stamp the date and test pressure on the test plate attached to each pressure vessel. If all available spaces on the test plate have been previously used, install a new test plate with the required test data stamped on it. The new test plate shall have sufficient spaces for at least 4 additional tests to be stamped.

4. QUALITY ASSURANCE.

4.1 The COTR or another designated NOAA representative shall

witness all hydrostatic tests and relief valve settings.

4.2 Provide to the COTR two copies of a test report containing the Contractor's name, test pressure, relief valve setting, and date for each test performed.

END OF SPECIFICATION