API 5L question

[OwaisGillani]

hi

Is it possible in any way for the buyer to specify line pipe dimensions with constant ID and different OD? e.g. pipe of ND 18-inch but with constant ID of 425.2mm and wall thicknesses like 14.5, 16 and 18 mm. I have gone through API 5L (very thoroughly again and again)and all I find is OD and wall thickness and I have been doing it in the same way for a long time.

Now some management guy is convinced that it is better to go with constant ID. I don't have the time to go into a lengthy argument so basically I am looking for a nail-in-the-head type of reply.

Also I think all the pipe manufacturing processes being used commercially control pipe OD. Has anybody ever bought line pipes specified with constant ID?

Any comment...!

 

[nickelkid]

please do not double post

 

[IFRs]

If you vary the OD then flanges won't fit.

 

[OwaisGillani]

Well RCHandy, it is not a double post at all.

I posted this question on API code issues forum to know the opinion of people with expertise in API 5L code and its code cases. Here, I am asking all the personnal who are experienced in piping and fluid mechanics which off course is not limited to B31 codes and ANSI or API pipe specifications. Here my question is directed to a more diverse group of experts.

I want to know whether anybody has ever ever specified and purchased pipes based upon constant ID? While the case referred in my original question is based upon API 5L spec, but the replies can refer to any piping code and any pipe spec from around the world.

So, I repeat my question again for clarity. Has anybody ever specified and purchased pipes based upon constant ID?

Any replies?

 

[OwaisGillani]

hi IFRs

Though it is off the topic, but welding neck flanges can be used without any problem.

 

[europipe]

Kick the management guy his ass.

Greetings

 

[BigInch]

While its true that you can make any type of pipe you like, it is undoubtedly better to stick with the conventional sizes. A large diameter gas line going from TX to NY is 31" and more than one problem has resulted with that.

As you're talking to management, remember they always wind up looking for a scapegoat if things don't work out well, so be very careful, or your "nail-in-the-head answer" might turn into a nail in the coffin. If its operational management, no "might" about it. It is already.

**********************
"Pumping systems account for nearly 20% of the world’s energy used by electric motors and 25% to 50% of the total electrical energy usage in certain industrial facilities." - DOE statistic (Note: Make that 99.99% for pipeline companies)

http://virtualpipeline.spaces.live.com/

 

[rconner]

I am not going to claim specific expertise here (and I suspect as BigInch indicates Owners nowadays might get a manufacturer somewhere, whether or not it is the best alternative in the long run, to say they would make about anything if that’s what an Owner thinks they want!) Perhaps only your suppliers, installers and users/maintainers etc. could tell you exactly what all problems in the life cycle might be involved with varying pipe outside diameters every time a wall thickness changes (i.e. going with perhaps even several different “special” outside diameters --while some problems are mentioned on this thread, I suspect there could be many more.)

I believe while not necessarily dictating outside diameters ANSI/API Specification 5L at least refers e.g. to ASME B36.10 for “Standardized values for specified outside diameters…” etc. It follows that at least some things not “standardized” are likely to be to some extent somewhat special orders for at least some manufacturers, that are in turn perhaps not necessarily what the manufacturer forms, makes, welds, ships etc. every day. Also, when any supplier makes and ships something special, obviously they are likely making something other than what they (and their equipment in some cases) have the most manufacturing experience with. Perhaps the manufacture of high grade pipe, and for its typical services, is an area where you want very good, or the best, experience possible.

 

[BigInch]

... And order pleanty of extra pipe so you don't have to wait 8 months to fabricate new stuff everytime that you need to replace a damaged joint.

Its really better to stick with a standard size whenever a standard exists. Meer mortals often cannot forsee the full implications of deviating from standard sizes.

**********************
"Pumping systems account for nearly 20% of the world’s energy used by electric motors and 25% to 50% of the total electrical energy usage in certain industrial facilities." - DOE statistic (Note: Make that 99.99% for pipeline companies)

http://virtualpipeline.spaces.live.com/