Can Pipeline Inline Inspection replace hydrotest?

[NATIVES]

i have a company wishing to perform Pipeline Inline Inspection (ILI) utilizing Mechanical Feeler Defect Sensing (MFDS) to replace hydrotest requirement. Is inline inspection to detect defects as good as hydrotest?

 

[BigInch]

No. A pressure test is mandatory under ASME B31.4 & 8.

Independent events are seldomly independent.

 

[LittleInch]

And required by every other design code, safety authority, regulatory authority and insurance company / funding bank I have ever heard of.

By the way, what is MFDS?, I googled this having never come across the term before and it didn't come up.

My motto: Learn something new every day

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

 

[brimmer]

In Canada we actually have reliability based design, which does not require a hydrotest, but documentation during construction up the wazoo, nothing to do with running a geometry tool in the line though. Though it is a good idea to run one of these after construction to see what kind of dents the contractor put in the line during construction and make them pay for repairs for any that meet a defined criteria, but we don't run this in lieu of a hydrotest.

 

[BigInch]

B31.3 only requires a "leak test", as opposed to a strength-type, pipeline hydrotest .. IMO different.

brimmer, when was that provision adopted? Has it always been the case, or is it relatively recent?

Independent events are seldomly independent.

 

[brimmer]

It has been updated in the 2011 version of CSA, so relativley new

 

[rconner]

While I’m not going to say any particular procedures or allowances are wrong or don’t work in any specific case, I will say that when the purpose of a pipeline is to contain/carry fluid/pressures (and maybe particularly so under high pressure) it may be pretty darn hard from at least a common sense standpoint to beat a well run hydrostatic test (in as close as possible the fully installed and loaded condition). Furthermore, I think well run hydrostatic tests have done a pretty good job over many decades of protecting the long-term interests of all parties to pipeline projects (including the public).
On the other hand, there have also been many, and sometimes quite inventive or imaginative arguments with rather convincing local justification or rationalizations, to avoid hydrostatic testing. I guess I’ve seen a problem or two in the now near forty years I’ve been around the pipeline business where it was confirmed that for whatever reasons properly run hydrostatic testing was not done, and problems were later discovered in/from the pipelines.

 

[BigInch]

Ive busted a couple of them in a hydrotest. Its usually better to do that when they're full of water.
Until B31.4/8 change, I guess we can take advantage of the big experimentation area north of the border.

"Learn from the mistakes of others. You can't live long enough to make them all yourself."
Elenor Roosevelt

Independent events are seldomly independent.

 

[KevinNZ]

We use B31.1 for geothermal pipelines. this allows leak test if the owner agrees. With our large CA the hydro test does not put much of a stress in to the pipe anyway. The hydro test becomes a cold water leak test.

Kevin