Engineering Assessment During New Construction 3

[auzie5]

I’m curious if anyone here has ever completed an Engineering Assessment (EA) to support a non-conformance to a code requirement during new construction. This is primarily a philosophical question since CSA Z662-15 is unclear regarding whether or not an EA can be adopted at the construction stage.

It usually never comes up since we typically just remove any defects that are discovered at the construction stage. However there are some extreme cases where it may not be practical to remove a defect that can be shown to pose no integrity concerns for the pipeline system.

Example:

After pipeline construction but prior to commissioning, an ILI caliper tool run identifies ovality in a section of the pipeline. The ovality is measured to be 6%. Estimated cost to remove and replace the section of pipe with ovality is one million dollars. An engineering assessment of the ovality demonstrates that the ovality does not jeopardize the integrity of the pipeline system.

However, the pipeline is built to CSA Z662-15. CSA Z662-15 Clause 6.3.4.2 states, “Pipe out of roundness shall be limited to the difference between the maximum and minimum diameters not exceeding 5% of the specified outside diameter of the pipe. Pipe not meeting this requirement shall be removed”.

Nowhere in CSA Z662-15 Clause 6 does it state that an EA can be used to support a non-conformance to a code requirement during new construction.

Any thoughts? Has anyone here ever completed an EA to accept a non-conformance to a code requirement during new construction using any other codes? Possibly on an offshore pipeline project where repair costs tend to be relatively high compared to onshore repair work?

I appreciate any insight provided on this matter.

Thanks.

 

[BigInch]

Why would anyone accept a deviation from minimum code requirements? If the out of roundness was slight enough to pass minimum code requirements, but I questioned you if it was OK, given the weight of the earth that you were piling on top of it and you did the calcs and proved to me that it was OK, then we could talk about it.

But if it was greater than what code allowed, then the proponent has supposedly issued the construction contract requiring design, construction installation to CSA Z662-15, including Clause 6.3.4.2. The proponent simply needs to tell the contractor to cut it out and fix it at the contractor's cost. Shortcutting codes is very bad practice. Doing so knowingly can be illegal and possibly extremely serious should the worse happen. There is no incentive for the regulatory authority to accept deviations. They have their legal requirements Z662-15. Approving a deviation may expose them to liability. There is no incentive for the owner to accpet anything less, in fact it is even more likely to result in liabilty should he do so.

With the above reasons at hand, fortunately, I have never had the necessity to do anything other than to require the contractor to make all appropriate corrections.

Now you should take this little piece of paper, memorize it, burn it, pretend you always knew the answer and never ask the question again.

"He's declaring war on the planet itself."- Vicente Fox

 

[auzie5]

As always, I appreciate the reply BigInch.

Of course a contractor is obligated to deliver a defect free pipeline and we do not accept anything less. It is just a hypothetical scenario. There are acceptable ways to evaluate anomalies that can and do exist in pipelines. Where a fit-for-service evaluation of a defect concludes a line is fit-for-service, lines are left in service with an appropriate monitoring program. The same level of rigor can be applied to evaluating a defect discovered during the construction phase. We have never been in a position where we could not make necessary repairs during the construction phase. But I do wonder to myself if I would be willing, in extreme circumstances, to bankrupt a contractor to repair a defect that has been demonstrated to not render a line unfit-for-service.

 

[BigInch]

I thought I made a clearer distinction between violating code minimums and approval of a non-critical deficiency. There would be no need to bankrupt anybody over a noncritical deficiency. A deficiency that violates code is an entirely different story and is always a critical deficiency. You don't need to be approving those kinds of deficiencies or any other deficiency that you cannot verify to your satisfaction will remain within safe limits. I can tell that, if you're really wondering what you would do about it today, it's above your pay grade. In fact not ensuring that the contractor corrects them is essentially the same thing as stealing from your employer. I'd fire you immediately on suspicion of taking a bribe if nothing else. Besides, should the worse happen and defect comes to light 20 years from now as part of a fatal accident investigation, well after the contractor has gone bankrupt for messing up a different job and your name just happens to be found on the work approval and somebody calls and asks if you can explain that, I hope your story will be a good one.

"He's declaring war on the planet itself."- Vicente Fox

 

[auzie5]

As always, I appreciate the reply BigInch.

 

[BigInch]

Welcome. My best advice is to never approve anything except work done to your satisfaction. Always kick the questionable ones up to your boss. If you're the CEO, then hire independent engnineers to evaluate the situation and do what your lawyers tell you to do.

Nobody does either one's self, or the industry any good trying to help bad contractors stay in business another few months or so. It's only a matter of time, so the sooner they bankrupt themselves (that's when the owners run off with the money), the less harm is done to all. Good riddance.

Always require that the contractor furnish a bond of sufficient amount to guarantee the work can be finished should the original contractor fail for one reason or another to complete.

"He's declaring war on the planet itself."- Vicente Fox

 

[auzie5]

I am posting this as a follow-up to the correspondents (above). Please note, I am not posting this to provide owners or contractors with an alternative to meeting the workmanship standards we expect from them (which are typically defined in pipeline codes, regulations, etc.). This is simply a pertinent clarification on the position that CSA takes related to performing engineering assessments at the construction stage. It is also a correction to my original post that stated, "Nowhere in CSA Z662-15 Clause 6 does it state that an EA can be used to support a non-conformance to a code requirement during new construction.".

Anyone who adopts this approach would do themselves a favor by reflecting on the comments from BigInch (above). A decision to perform an EA (as outlined below) is a decision that should not be made carelessly.

Clarification:

The 2015 edition of the CSA Z662 standard (i.e. CSA Z662-15) was revised to provide a clear path for using an engineering assessment to evaluate ovality at the construction stage.

​

CSA Z662-15 Clause 6.2.3 (Bends and Elbows in Steel Piping), Sub-Clause (a) and Item (i) and Sub-Clause (b)

​

“For steel piping, changes in direction may be made by the use of bends or elbows, or both, subject to the following limitations:

​

a) Out-of-roundness of the cross-section within the bend shall be controlled so that it is not detrimental to the structural integrity and normal

​

operation of the pipeline system. Where applicable, allowances shall be made for the installation of liners and for the passage of internal inspection tools

​

and pipeline scrapers. Unless the effects of bending are determined through an engineering assessment to be within acceptable limits, the following

​

limitations shall apply:

​

​

(i) See Clause 6.3.4 for buckles, ripples, wrinkles, and out-of-roundness acceptance criteria.

​

(ii) For field cold bends of pipe 323.9 mm OD or larger, the longitudinal axis of the pipe shall not be deflected more than 1.5 deg in any length along the axis equal to the outside diameter of the pipe.

​

b) Where the effects of bending on the mechanical properties of the pipe are determined through an engineering assessment to be acceptable, the limits in items a i) and ii), may be exceeded.”

CSA Z662-15 Clause 6.3.4 (Ripples, Wrinkles, Buckles, and out-of-Roundness), Sub-Clause 6.3.4.2

​

“Pipe out of roundness shall be limited to the difference between the maximum and minimum diameters not exceeding 5% of the specified outside diameter of

​

the pipe. Pipe not meeting this requirement shall be removed.”



Additional note
• CSA Z662-15 is the first addition where a limit for straight pipe out-of-roundness is defined (refer to CSA Z662-15 Clause 6.3.4.2).
• In CSA Z662-15, the out-of-round limit for straight pipe is the same as the limit that applies to bends and elbows (refer to CSA Z662-15 Clause 6.2.3).

 

[BigInch]

So essentially that code now says variance to roundness minimums are permitted, if approved by the engineer. That's great. Exactly as it should be.

Richard Feynman's Problem Solving Algorithm
1. Write down the problem.
2. Think very hard.
3. Write down the answer.