6 007 leak checking helium

Approval

$$ 1 City Colt $$

Revision History

1

Purpose

1.1 To establish a standard format for helium leak checking of high purity gas lines.

1.1.1 INBOARD TEST: Helium is sprayed on all joints – mechanical and welded – while the line is kept under a deep vacuum (less than 5 torr).

1.1.2 OUTBOARD TEST – The line is filled with helium and a tracer probe (sniffer) is used to detect any possible leaks at mechanical or welded joints.

2

Scope

2.1 This procedure applies to testing high purity gas lines using helium leak detectors capable of sensing leak rate of [1x10 ] cc/sec or smaller (inboard test).

-6 Note: Outboard tests are performed with a sensitivity of [1x10 ].

3

Responsibility

3.1 Therma’s general foreman is responsible for performing the tasks listed herein.

3.2 Project Manager is responsible for coordination with Owner, GC & Jurisdictional Authority as required to witness testing start and finish.

4

Reference

4.1 Operating manual for helium leak detector.

4.2 ANSI/ASME B31.3 Process Piping, Current Edition.

5

Safety

5.1 Foreman shall maintain safe working conditions throughout the process of leak testing including provisions for pre-task planning, hazard marking/signage and awareness, LOTO, pre-test inspections and barricades, etc.

5.2 CAUTION : Pneumatic testing involves the hazard of released energy stored in compressed gas. Particular care must therefore be taken to minimize the chance of brittle failure during pneumatic leak test.

5.2.1 If a pneumatic leak test would present unacceptable hazards, such as risk of brittle fracture at the metal test temperature, then a substitute for pressure testing should be developed.

5.2.2 See ASME PCC-2 for information regarding the need for risk analysis.

6

Definition

6.1 Torr: Unit of pressure equal to 1/760 of a standard atmosphere (14.7 psi)

6.2 cc/sec: Cubic centimeters per second (leak rate measurement)

7

Materials Requirement

7.1 Test port adapters.

7.2 Helium cylinder, spray gun, and helium tracer probe (sniffer).

8

Test Equipment

-9 8.1 Helium leak detector capable of sensing leak rates of [1x10 ]

9

Procedures

9.1 Therma’s general foreman is responsible for verifying system assembly is complete and leak testing is complete.

9.2 Project Manager is responsible for coordination with Owner, GC & Jurisdictional Authority as required to witness testing start and finish.

9.3 The QC Manager shall ensure the leak detector calibration is NIST (National Institute of Standards and Technology) traceable.

9.4 Verify with the PM when it is safe to test.

9.5 Be sure to notify the owner or owner representatives to witness and sign the pressure test log if required.

9.6 Record the customer’s specifications for helium leakage on Form FN 7.027.1 (Analytical Test Report).

9.7 Isolate the tube/line to be tested.

9.8 Start-up and calibrate the helium leak detector.

9.9 Connect the tube/line to be tested to the helium leak detector’s test port.

9.10 Follow proper operation steps as per operating manual for each helium leak detector.

9.11 The Quality Control Examiner (QCE) or process piping foreman shall perform or witness Owner/3rd Party Inspector (OPI) performance of the testing. The tester shall begin with helium spray on the nearest joint to the detector working outwards to avoid upstream contamination in case one or more joints are found to be leaking.

-9 9.12 Test shall be performed in the [1x10 ] sensitivity range or as specified.

$$ [1\times10^{-9}] $$

9.13 Detected leaks shall be recorded on form FN 7.027.1.

9.14 If detected leak rates exceed the customer’s specifications the QC Manager shall immediately notify the PM to repair all the leaks.

9.15 After all repairs are made and line pressure checked again, repeat steps 9.1 through 9.14.

9.16 If no leaks are detected or the leak rates detected are within the customer’s specifications, proceed to the following step, the line shall be filled with high purity Argon.

9.17 Tested lines shall be tagged appropriately: ‘Passed’ or ‘Failed’.

9.18 If the line passes, hang the ‘Passed’ tag. Otherwise, hang the ‘Failed’ tag. The QC Manager shall notify the Project Manager of current status.

9.19 Replace/restore all removed instrumentation and reconnect all equipment. Remove all “PRESSURE TEST IN PROGRESS” tags.

10

Review and Approval

10.1 QC Manager or Owner/3rd Party Inspector shall submit the Helium Leak Testing Report to the PM.