Prohibition of Reinforced Thermoplastic Pipe for Offshore Pipeline (Liquid & Gas Hydrocarbon)

[ek4putr4]

Refer to ASME B31.4 Chapter IX section A423.2 and ASME B31.8 Chapter VIII section A811, is there any reason why plastic pipe with non metallic reinforcement such as RTP pipe is prohibited to be used for offshore liquid pipeline system under ASME B31.4 or for gas transmission line under ASME B31.8?

 

[BigInch]

It melts and is a great fuel.

"People will work for you with blood and sweat and tears if they work for what they believe in......" - Simon Sinek

 

[ek4putr4]

But, why it is allowed for onshore application? If melting is the issue, it shall be prohibited for both onshore and offshore application.

 

[BigInch]

I think it is allowed for underground pipelines in B31.8.
As far as I know it is not allowed in liquid pipelines under B31.4
Some pipelines are "flowlines" and are designed to B31.3

"People will work for you with blood and sweat and tears if they work for what they believe in......" - Simon Sinek

 

[ek4putr4]

For ASME B31.4, I couldn't find wording that RTP is prohibited for onshore application, even though the RTP is also not listed in the table, but section 423.1 (b) --> Except as otherwise provided for in this Code, materials which do not conform to a listed specification or standard in Table 423.1 may be used provided they conform to a published specification covering chemistry, physical and mechanical properties, method and process of manufacture, heat treatment, and quality control, and otherwise meet the requirements of this Code. Allowable stresses shall be determined in accordance with the applicable allowable stress basis of this Code or a more conservative basis

The above allowing for using of usage of other material.

But what is the reason that make it specific : prohibited for offshore application?

For ASME B31.8, is there any reason it is allowed for buried pipeline, but prohibited for offshore pipeline?

 

[MikeHalloran]

Self-evident: When an offshore rig catches fire, you don't have the option of jumping in your pickup and driving away from the danger.



Mike Halloran
Pembroke Pines, FL, USA

 

[ek4putr4]

But what is the difference with flexible pipe (API 17 J), and also some sort of rubber line (API 17K) but with steel reinforcement. If fire occur, both will provide similar effect as RTP.

So what specifically prohibit Pipe with "non metallic reinforcement" type is prohibited?

 

[BigInch]

Basically B31.4 and 8 pipelines are ment to be BURIED. That's the general idea. Miniscule to no chance they will catch fire being underground. The last thing you need anywhere for that matter is the pipe catching fire. I wouldn't use any plastic pipe anywhere that would catch fire to pipe anything except water.

Non-metallic reinforced, plastic pipe loses strength over time.

"People will work for you with blood and sweat and tears if they work for what they believe in......" - Simon Sinek

 

[patprimmer]

Almost all plastics are permeable to hydrocarbons to some extent, especially the lower molecular weight fractions, so the area surrounding the pipe might build up hydrocarbons to a level that provides an explosion risk. This is why you should never sore fuel in a plastic container in a confined space unless the plastic container has been treated with fluorine gas to chemically seal the pores.

Also as already mentioned plastics melt at relatively low temperatures and most burn well.

Rubber is also permeable to hydrocarbons.

Steel braiding reinforces pipe from stretching to much and bursting under load, but does not protect all that well to crushing and does not offer any barrier to permeation of the hydrocarbons through the pipe.

Regards
Pat
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[zdas04]

What nonsense. The risk of a fire in non-metallic piping is very similar to the risk in metallic piping. Any time there is a code that excludes (or even prohibits) reinforced composite piping it is generally because the code has not been updated. FlexSteel was developed for offshore applications and is specifically reinforced against anchor-drags (the main failure mode of subsea pipeworks). There are thousands of miles of this stuff in the ocean in both gas, oil, and produced water service as we speak. If a code (and I don't use B31.4 so I can't speak to it directly, but B31.8 has good things to say about spoolable composites) explicitly prohibits it, I couldn't tell you what they were thinking, or when that "thought process" occurred.

David Simpson, PE
MuleShoe Engineering

"Belief" is the acceptance of an hypotheses in the absence of data.
"Prejudice" is having an opinion not supported by the preponderance of the data.
"Knowledge" is only found through the accumulation and analysis of data.

 

[BigInch]

In any case you may need to comply with API RP14E as well.

"People will work for you with blood and sweat and tears if they work for what they believe in......" - Simon Sinek

 

[SJones]

The scope of API RP 15S states "for offshore use, additional requirements may apply." It suggests that applying RTP pipe offshore hasn't got round to being thought of seriously just yet. It takes a while, and a number of joint industry projects to get over the 'it's not in the code' hurdle.

Steve Jones
Materials & Corrosion Engineer

http://www.linkedin.com/pub/8/83b/b04

All answers are personal opinions only and are in no way connected with any employer.

 

[BigInch]

Do you think BP will do it?

"People will work for you with blood and sweat and tears if they work for what they believe in......" - Simon Sinek

 

[zdas04]

Funny question. The original development of spoolable composite pipe got seed money from a project managed by George King, an Amoco Research Center employee. George eventually retired from BP, but he was instrumental in the early deployment of this pipe including to Amoco's facilities offshore. The new BP might not take the risk, but the old BP was a leader in that technology.

David Simpson, PE
MuleShoe Engineering

"Belief" is the acceptance of an hypotheses in the absence of data.
"Prejudice" is having an opinion not supported by the preponderance of the data.
"Knowledge" is only found through the accumulation and analysis of data.

 

[ek4putr4]

API 15S was a JIP output. However it is not a spec, just recommended practice. With recent development in composite pipe, RTP is not just kevlar reinforced thermoplastic, but also glas fibre, combined glas - kevlar reinforcement, bonded and unbonded structure. They are trying hard to fit in API 17B, 17J & K. I know the limitation to temperature, long term strength, non plastis burst, permeation issue, etc. But still cannot understand why onshore application is allowed, but offshore is explicitly prohibited.
Agree with SJones, for offshore use, additional requirement may apply. In my thought are collapse and buckle, tension, torsion, on bottom stability, installation, external impact, etc, similar to steel pipe.
However, the main code, B31.4&8 is explicitly prohibit it for use in offshore.

 

[BigInch]

Not ready for prime time. There are still many unanswered questions concerning long term performance issues of non-metallic products.

There is only one instance that I know about where Reinforced Thermo-Plastic products are PROPOSED TO BE tested in a regulated environment, actually in a Class 4 location if you can believe it, outside of totally UN-regulated gathering systems. Offshore is regulated territory. Highly regulated. It will be awhile, if ever.

zdas, "the old BP was a leader in that technology"; risk management technology I presume.

"People will work for you with blood and sweat and tears if they work for what they believe in......" - Simon Sinek

 

[zdas04]

Fiberspar's web page used to have a speedometer looking thing that said 8 million miles installed and counting. FlexSteel advertises "over a million miles installed". Others are similar. This stuff is so good that it will not be held back by idiots on quasi-regulatory committees of ASME, API, or ISO.

BigInch, I'm ignoring the jape.

David Simpson, PE
MuleShoe Engineering

"Belief" is the acceptance of an hypotheses in the absence of data.
"Prejudice" is having an opinion not supported by the preponderance of the data.
"Knowledge" is only found through the accumulation and analysis of data.

 

[BigInch]

Nor by idiots offshore either?
I actually think that the stuff looks very promising, but no way I would use it in any location that could be exposed to fire. Don't make sense to risk a nice big money-making pipeline just for saving a few thousand dollars.

"People will work for you with blood and sweat and tears if they work for what they believe in......" - Simon Sinek

 

[zdas04]

I use it everywhere that they have a size the fits the application and have for 10 years. Today 6-inch products are widely available I and I wish the spools were longer, but I still use it. I've never been terribly concerned about fire on pipelines--mostly I bury them and dirt don't burn. Seriously, I have never seen a pooling liquid fire outside of a plant fence. Every fire I've investigated has been a jet fire that cut through steel pipe as fast as it would have cut through plastic. The fire thing really is a non-issue.

David Simpson, PE
MuleShoe Engineering

"Belief" is the acceptance of an hypotheses in the absence of data.
"Prejudice" is having an opinion not supported by the preponderance of the data.
"Knowledge" is only found through the accumulation and analysis of data.

 

[rconner]

While not diminishing any claimed utility of the same nor intending to in any fashion pick sides in this educational debate, the FlexSteel pipe as detailed at e.g.

http://www.flexsteelpipe.com/products/pipe-specifications

does appear some limited as far as pipe size, tensile/pulling load and maximum water depth capabilities (that I would think could be judged important in much "offshore" work). Also, it also looks like the "FiberSpar" pipe may still have the (McDonalds-style?) lifetime aggregate production sign/banner still up and running now at the website

http://www.fiberspar.com/#

, though it appears to date with a magnitude "50,000,000" FEET displayed (scrolling, fifth balloon in banner) .
While I guess this amount of pipe is meant to sound like a lot, maybe (with less than 10,000 miles total?) it may not really be a whole lot yet in the whole energy pipe market/scheme of things.