Friday, November 20, 2009

Air Leak Test

General
This document presents minimum requirements of air leak test that will be applied of reinforcement pad of storage tank.
Particular attention of this test is leakage detection that shall be applied to circumference finish fillet weld reinforcement plate to shell on each opening using tell-tale hole before the tank is filled with test water.

Testing Apparatus

Compressor – 1 unit
Pressure gauge – 1 unit
Flexible hose
Soup solution


Testing Method

Applying pneumatic pressure and soup film as media of finish fillet welds between reinforcement plate and shell for Leakage detecti
on.

Preparation
i) Pneumatic pressure test shall be performed after visual examination.

ii) The joint should be thoroughly cleaned from debris and foreign materials using suitable cleaning process.

iii) Keep dry of surface area that will be tested.

iv) The temperature limits of metal surface shall be between 4o C (40 o F) and 52 o C (125oF), unless the film solution is proven to work at temperatures outside these limits, either by testing or manufacturer’s recommendations.

v) Prepare soup solution suitable for detection of leak.

vi) A minimum light intensity of 1000 lux (100Fc) at the point of examination is required during the application of the examination and evaluation for leaks.

vii)The examiner shall has vision (with correction, if necessary) to be able to read a Jagger Type 2 standard chart at distance of not less than 300 mm (12 in).

viii) The examiner shall competent in the technique of the pneumatic pressure testing, including performing the examination and interpreting and evaluating the results.

Test Execution
i) Applying pneumatic pressure to the each opening of 100 kpa (15 lbf/in2) and hold pressure.

ii) Verifying and Examine the weld of outside tank for evidence of leakage.

In case the leakage happens of welding seam, it will be indicated with formation of bubbles and pressure drop indicated at pressure gauge. If leakage found, Identify using marker at leakage area for repair work and retested.
iii)
Result of test shall be documented and maintain.

iv) When rainfall during a test makes the checking for leaks, required agreement between COMPANY and CONTRACTOR that the test shall be postponed until weather permits possible to inspect.

v) The tested surface shall be cleaned and dry, after pneumatic pressure test complete.

Acceptance Criteria
There is no bursting bubble at welding seam tested.


Repair of Defective Welds
i)
Defect in welds shall be repaired by grinding or chipping or melting out the defects and re-welding in accordance with previous WPS.

ii) The repair weld shall be retested as paragraph 5.


Attachment

- Inspection Record of Air leak Test




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