Untitled - Future Pipe Industries

7.6: Final pressure test
After all backfilling has been completed and the entire pipeline construction has been completed (except at the closing ends
or tie-in joints of the pipeline), the line shall be subjected to a final pressure test following the same basic procedures described
in section 7.5. The final test pressure is generally equal to 1.25 times the intended working pressure of the pipeline (unless
otherwise specifi ed by the Engineer). The duration of this test shall not be less than two hours, or the time to determine by
visual inspection the closure joints and the overall soundness of the entire pipeline, whichever is greater.
7.7: Testing according to method type 2 (using a joint tester)
Field testing using method type 2 is applicable only for diameters of 36” and above. This method is recommended in the
case of:
• Non availability of a suitable water supply source
• Unstable soils, which pose a potential problem in the case of use of test method 1
• Very Large diameter pipelines where traditional pipe section pressure test is not feasible
7.7.1: Preliminary test (method 2)
As laying proceeds, each coupling is tested for its water tightness by applying internal hydrostatic pressure by means of a
mobile joint testing apparatus fitted internally and designed to straddle the gap between the pipe ends. Through the pressure
applied, a high thrust results, and the pipes must be solidly anchored and wedged laterally.
The last pipes laid must be at least 2 pipes ahead of those to be tested. Prior to the test, the pipe sections must have at least
0.5 x D of cover above the pipe crown, with a minimum of 12”. It is not essential to leave the joints exposed to ambient
atmosphere in this test method. The test pressure shall be 1.5 times the intended working pressure of the pipes.
Caution: Pipe joint testing shall be performed in well ventilated pipelines only. The safety of the operators inside the pipe
must always be assured. For safety considerations, the operators must work at the free end of the joint tester (near to the pipe
open access). All operators must be securely hooked to a guide rope to other workers terminating outside the pipeline to
allow pulling them out from the pipeline in the case of an emergency. Safety personnel must review the proposed testing procedures
to insure the safety of the workers inside the pipe. All possible causes of trench flooding must be identified and
appropriate safeguards taken.
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