Piping and pipeline codes

[engr2GW]

Hell,
This question is for US onshore oil and gas production facilities and gathering flowlines.
For lines that are typically in the middle of nowhere, and in ranches where there are barely any houses. We use ASME B series as the governing code for our tank batteries and pipelines (31.3, 31.4, and 31.8).

In environments like that, is that a proper code to apply, most companies I know in the Shale business and onshore use those codes.

Secondly, what is the place for DOT regulations. An approach is to evaluate for DOT 49 CFR 19...applicability on a case by case bases (depending on evaluation of location) and use the ASME B31 series as the main codes to apply...Is this a good approach?

As much as possible, do it right the first time...

 

[1503-44]

You have to be a bit careful in the USA. It is basically Title 49 that applies as the law. but ASME B codes apply also, as they are referenced in Title 49, however pay attention to the years of edition of the ASME codes that are referenced, as they are not the latest ASME editions. See 192.7

Part 192.8 and 192.9 discuss requirements for gathering lines. It references an API document, RP 80 to define exact start and end points of gathering lines, but IMO that doc is written for tax accountants and IRS people and I'm sure your understanding of what a gathering line is adequate already. Basically those lines going from the well's flow meter to the tanks, or to something like a gas dehy, treatment, metering station, or processing plant.

It used to be that onshore gathering lines in the middle of nowhere were not subject to any regulation. That has changed a lot in recent years and many now fall under the CFR regulations, but some still do not. IMO, that makes a difference to mostly PHMSA inspection, material requirements, and traceability, record keeping, certain operations reporting requirements and other legal matters. I say that because, even though some gathering lines and pipelines are regulated and some are not, I have always believed that a pipeline still needs to be designed to operate safely and the best way to ensure that is to simply design all of them to CFR/B31 design requirements. I started applying the technical design requirements of the CFRs and ASMEs to all the pipelines and gathering lines that I designed in the remote South Texas gathering fields way back in 1980's, when virtually nothing out there was regulated at all. As the technical requirements of the CFR regulations and ASME codes only prescribe the MINIMUM requirements for pipelines of all kinds, you really cannot obtain any long term benefits by not using them, assuming that you do want your design to result in a safely operable system. I mean what are you going to do otherwise, push the hoop stress design factor to 0.90. Not use a corrosion allowance in a gathering system? The basic cfr/asme design requirements are in reality quite minimal. Squeezing those is likely to pop the seams in other areas. So, for design purposes, I feel that there is not much to be gained by not using the codes. DOT/PHMSA reporting requirements and recording keeping might be easier, but IMO, you will one day need those records anyway. I just always do design by the cfr/code and sleep peacefully at night.

Did I answer your questions?

 

[LittleInch]

The bit that has always got me is that B31.8 is not officially valid for flowlines as it is two or three phase fluid. I think B31.4 has similar restrictions on its "official" validity for flowline design. They are though widely used for this service, in theory they don't cover well fluids (oil, gas & water mixture)

I'm not actually sure what you're supposed to use - B31.3??, but that sucks for pipeline design.

But definitely go for a pipeline code vs anything else and just be judicious on the design factor (nothing higher than 0.72) or corrosion allowance (1-3mm).



Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[1503-44]

Online copy f the 2002 edition, I think that is the one that the CFR Title 49 Part 195 (Liquid HC Transportation) references, is here,

https://archive.org/details/gov.law.asme.b31.4.2002/page/n20/mode/1up

See Section 400.1.1 Scope

"This Code prescribes requirements for the design, materials, construction ...
of piping transporting liquids such as crude oil, condensate, natural gasoline, natural gas liquids, liquefied petroleum gas, carbon dioxide, liquid alcohol, liquid anhydrous ammonia, and liquid petroleum products between producers lease facilities, tank farms, natural gas processing plants ..."

Would you not agree that "crude oil, condensate, natural gasoline, natural gas liquids" includes the bulk of the fluid mixtures normally found inside flow lines and that, as transport from producers lease facilities to other facilities is almost always coincident with the need to move various quantities of directly associated quantities of water, brine, condenstates and gases produced from the wells, that B31.4 must also include those fluids and gases? If it did not include these associated fluids and gases, B31.4 couldn't very well say that it was valid for transportation of hydrocarbons via pipeline "between producters lease facilities, tank farms, natural gas processing plants, refineries, stations, ... etc. as those pipelines ususally are doing precisely that. Validity of B31.4 & CFR 195 for flow lines must at the very least be strongly implied. I always took that position when submitting permit applications for offshore construction and onshore construction in BLM agency land and no permitting agency ever questioned that approach. Admittedly that was some time ago.

Once you get past the which code question, you can realize that there isn't a whole lot of difference between the codes in the design of the physical pipe and components anyway, other than class locations and block valve locations, that would really make a great difference in the design of a liquid or a gas pipeline, for example, as in wall thicknesses, configurations, safety equipment and all. For those certain instances where there are differences, the cfrs and codes are minimum requirements and there is nothing stopping the engineer from including specific features that he/she felt are necessary for safe design and operation. In fact it is required that the design engineer provide all things that he/she thinks is necessary to make it that way. So consider class factors of B31.8, if you think you need to in order to be safe. Don't include overpressure allowances, if you don't think that is appropriate. In effect, design for B31.4, but include all the provisions of B31.8 to handle any associated well gases, and remember to include every other thing you believe you need in order to create a safe and code compliant design as well.

 

[LittleInch]

Well that's the problem with having two pipeline codes, one for gases and one for liquids.

What happens when you have a mixture of the two?? No one seems to know. There is a code case for B31.8 where it explicitly states it is not valid for flowlines with multi phase fluid.

I agree that the end result is often fairly similar, but I was just noting this anomaly with the ASME B series remains.

Your idea to use B 31.4 initially and then if your location class following B31.8 gives you a lower design factor then use that is a sensible way to go.

Then yes no overpressure allowance as there is gas in there remember.

Document it properly and get someone (client, regulator, other competent engineer) to review it and it should keep you safe from law suits and make it easier to sleep at night.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[1503-44]

Wait. B31.4 specifically says "between producer's lease facilities and facility" X. That is exactly what a "flow" or "gathering line" is. Also refer to the schematic diagrams and it is perfectly clear that it is B31.4 that applies. The one and only potential arguement is, if associated gas, water and condensates can be in that flow line. I can tell you that it is, because you cannot possibly design a flow line without any associated gas in the stream, plus the old Minerals Management Service approved a number of my designs for flow lines running between GOM well platforms and production treating platforms for separation and dehy and subsequent transport in each of separate pure gas pipelines and pure liquid natural gasoline-condensate pipelines. And, as I said, if you are not happy with a resulting B31.4 design, due to high volumes of produced associated gas, then simply include any additional provisions you need that will adequately address your particular concerns.

Right, no 10% overpressure is permitted for gas lines.

 

[LittleInch]

You're quoting from an old version. My 2006 version has that but not the latest one.

However the key bit is that it transport "liquids". Not liquids and gas co mingled or multiphase fluids, but liquids.

Like I said - in reality there is no other code commonly used or even signposted within the ASME B system for multi phase flowlines other than B31.3 and only a mad person would use that for a buried flowline so I'm not surprised that it is used and accepted. My point is that STRICTLY according to the letter of the code, you shouldn't and you therefore should use something like ISO 13623 unless some other authority who is approving the design, be that client or regualtor tells you to use B31.4. or accepts its use as a valid design code.

One of the problems with the CFR thing is that they lifted whole sections of the relevant ASME B code and dumped it into the document as legislation / regulation and have then never updated it. The ASME codes get updated as you well know every two or three years and hence the CFR is now about 6 or more versions out of date if they are using the 2002 code. Madness. All they needed to do was say use the latest version of ASME B xx.x and saved themselves the bother of cutting and pasting it into their regulation.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[1503-44]

True in the EU. But he's asking about USA and ISO doesn't fly in the US, and technically, neither does B31.4/8. The law says CFR. 192 (Gas pipeline regulations) and 195 for liquid

192 Gas regulations

https://www.law.cornell.edu/cfr/text/49/192.1

See 192.1 a Applies to
(b) exception
(4) Onshore gathering of gas
(ii) through a pipeline that is NOT a regulated onshore gathering line

That means yes CFR 192 (Gas pipeline regulations) does apply to regulated gathering pipelines.

For liquids its CFR 49 Part 195

https://www.law.cornell.edu/cfr/text/49/195.1

195.1 covered all of the following, EXCEPT for %% a whole bunch of pipeline types, including onshore flowlines, see b-4 %%

SO ... what to do to design a safe unregulated flowline???
You must use CFR 192/B31.8 if it is regulated. If it is not regulated, as I said, my philosophy has always been to use B31.4, modified to address any particular concerns that you may have above and beyond for large quantity of gas, area class, etc.. REMEMBERING THAT THESE ARE NOT REGULATED, so you can follow that philosophy if you want, or you can develop some other one that suits you, including using B31.8, modified for liquids, or using ISO 13623! ANYTHING is better than nothing, so I did it as per my philosophy described above.

 

[alchemon]

The simple fact is that intrastate pipelines are not regulated by PHMSA and are regulated at the state level. Most states adopt CFR 192/195 but many have amendments.

Therefore if you are operating intrastate pipelines, you need to know the state and type of pipeline. PHMSA does not have jurisdiction to regulate many intrastate pipelines.

 

[1503-44]

The States adopt CFR 192 & 195 as a condition to receive Gov funding for the state's utility regulation authority to carry out DOT/PHMSA policy at the state level. That is an agreement to enforce the provisions of the CFRs within the state as minimum requirements. They may add additional requirements. As far as I know, only Alaska has somewhat more of an independent arrangement, but I am not familiar with those specific details.

The regulations have changed over the last few years as the result of a number of campers being killed on a remote right of way, I think it was in Arizona, and they now seem to cover many interstate and intrastate pipelines that were never previously included, but I have not been involved with those recent changes and cannot tell you specifically how they have been implemented.

In any case, the sensible and safe thing to do is design all pipelines to the appropriate code, whether they are regulated or not. You can't hardly do otherwise and wind up with a safe system anyway.

 

[alchemon]

1503-44, that is what I mean - you need to check if the State has only marginal additional requirements over the PHMSA minimums. Therefore, there can be things which XYZ State requires and/or regulates over the PHMSA minimums. Some things that I have heard about are not as marginal. For example, I am aware of certain States having very strict odorant requirements. Others do not adopt (aka have stricter rules) on things like Cathodic protection (some will not, for instance, allow certain alternative CP criteria).

It would have been more proper for me to say "Most States adopt CFR192/195 outright. But many have amendments".

 

[1503-44]

OK. Yes, that's absolutely true. In fact I might still have a study of those differences.