Hydrostatic Test Procedure [PDF]

Zitiervorschau

HYDROSTATIC TEST PROCEDURE

I.

Purpose 1. To establish guidelines in conducting hydrostatic pressure test for piping system. 2. To check the welded and flange connections of piping system for any possible leaks that may be present.

II.

Scope 1. This procedure covers all piping system to be tested hydraulically for pressure strength and leakage. 2. This procedure shall be in accordance with ASME Section VIII Div. 1 and 2/ ANSI B 31.1 and as per projects specifications DIV 85000 (Building Mechanical System) and DIV 86000 (Water Supply and Waste Management System) for the fabrication / construction of piping system.

III.

General Requirements 1. Personnel 1.a. personnel performing this test shall be designated and oriented on this test procedure. 2. Gauges 2.a. Gauges to be used shall be calibrated and certified by authorized testing laboratory. 2.b. Gauges to be used for the pressure test shall have a minimum graduation of 1.5 to 2 times of the design pressure the test pressure to be applied. 3. Testing Medium 3.a. The fluid to be used shall be clean fresh water.

IV.

Responsibility 1. EEI Subcon/EEI FOG shall be responsible for the initiating and performing this procedure for hydrostatic pressure test and its correct implementation. 2. EEI Subcon QC/EEI-QC shall be responsible in the conduct of inspection during and after hydrostatic pressure test and documentation of such inspection. 3. Client’s Representative shall witness and approve the completeness of such test.

V.

Procedure 1. Preparation 1.a. Prior to pressure test all weldings to the pressure parts shall are completed and shall be thoroughly cleaned of rust, grease, paint or other contaminants capable of masking a leak. Slags shall be removed and all tack welds and spatters should be grind smooth. Any welding on the pressure parts after the hydrotest will invalidate the hydrotest done and re-test will be required.

1.b. Vents shall be at highest point of the piping system to purge air pockets during water filling. 1.c. piping system shall be blinded or blanked-off at proper spots according to the order of test limits. 1.d. flange joints at which blanks are inserted to blank-off other segments during the test should be checked for tightness and possible sign of leaks. 1.e. At least two pressure gauges shall be provided where one is at the lowest and the other one at the highest location of the piping system in such a manner that gauges can function correctly. 2. Pressure Application and Inspection 2.a. Whenever possible the test pressure shall not be applied until the piping system and the test medium are approximately at the same temperature. 2.b. The pressure shall be gradually increased up to the specific test pressure and held continuously for at least 10 minutes and may then reduced to the design pressure (ASME VIII Div. 2) and held for such time as maybe necessary to conduct examination for the leakage, Examination for the leakage shall be done on all joints and connections. Note: For a system being hydrotested under direct sunlight test pressure shall be controlled by bleeding to avoid excessive pressure rise as the temperature increases to avoid over stress on material of pressure parts. 2.c. The hydrostatic pressure at any point in a piping system shall not be less than 1.5 times the design pressure or 14 kg/sq.cm (200 Psi) for a holding time of 2 hours. 2.d. In determining the actual value of pressure attained during testing, the pressure reading of gauge located above the piping system shall be the basis of acceptance. 2.e. Tested piping system shall be checked for possible leakage or a pressure drop during the holding time. In the event repairs or additions are made following the pressure test the affected piping system should be re-tested in accordance with the requirements. VI.

Acceptance Criteria 1. Acceptable Result – areas under test are considered acceptable when no visible leaks are found and no sudden or gradual decrease on the pressure gauge reading is observed throughout the duration of test. 2. Rejectable Result – continuous leaking and sudden or gradual decrease in pressure gauge reading and/or visible deformation due to pressure that indicates yielding of pressure parts.

VII.

Corrective Measure Due To Rejectable Result 1. Any leak observed shall be marked for repair and shall be subject for re-test. This procedure of testing and repair cycle shall be performed until there is no more leak to be found.

VIII.

Post Treatment

1. Vent shall be opened prior to opening of the water drain valve. 2. After the test, piping system shall be drained. The inserted blind removed, connections properly re-installed and temporary supports removed. IX.

Test Certificates 1. Test certificates shall be prepared in accordance with form number QCF-005 and QCF006.