FUEL PIPELINES

[RAJKUMAR96]

Please help me with the standards and codes whether the testing of the pipelines can be done after backfilling the trench?

 

[DekDee]

More information needed - pressure testing can be done after backfilling but a bit hard to do visual / RT (or any other tests required) after backfilling,
Regards,
DD

 

[RAJKUMAR96]

Dear DekDee,

My pipe has already finished its RT and Holiday test, Now my concern is only for the commissioning tests and my pipe is of B31.3.

 

[DekDee]

If you have not performed a hydro test and you have backfilled already I suggest digging up ASAP and then reading B31.3 thoroughly.
Here are a couple for you to consider:

345.2.2 Other Test Requirements
(a) Examination for Leaks. A leak test shall be maintained
for at least 10 min, and all joints and connections
shall be examined for leaks.

345.3 Preparation for Leak Test
345.3.1 Joints Exposed. All joints, welds (including
structural attachment welds to pressure-containing components),
and bonds shall be left uninsulated and
exposed for examination during leak testing, except that
joints previously tested in accordance with this Code
may be insulated or covered. All joints may be primed
and painted prior to leak testing unless a sensitive leak
test (para. 345.8) is required.

 

[BigInch]

The pipe and joints should have been visually inspected first before burial.
You can test pipelines under B31.4 and B31.8 when buried, in fact it is preferred to do so.

Learn from the mistakes of others. You don't have time to make them all yourself.

 

[LittleInch]

RajKumar,

one of your issues is that you refer to this as a "pipeline", but then quote a piping code (B 31.3). B 31.3 doesn't do buried piping very well and you need to make sure that the "pipeline" is actually piggable, otherwise you are in trouble.

IMHO, testing of pipelines should occur with the pipeline in its "as installed" condition, i.e. laid in trench, backfilled (maybe not final re-instatement) and all connections and below ground / above ground connections made.

Testing in fuel systems is normal and just requires that you clear out the water using pigs initially then perhaps either a swabbing run with a MEG or similar, vacuum dry or just accept that the first few cubic metres will have some water in it. what you need to do varies with each system.

My motto: Learn something new every day

Also: There's usually a good reason why everyone does it that way