PED vs ASME B31.3 Cat D Fluid 1

[tommyb96]

Hello All,

I'm hoping for some help with a question that has arisen around pressure testing new pipework.

I have a fluid (instrument air) that would be classified as Category D under ASME B31.3 (i.e. safe, <150 psi, < 186 DegC, >-29 DegC).

Under ASME B31.3 I do not need to carry out a hydrostatic test, this can be proven through an initial service leak test (345.1/345.7).

My question is, how does this relate to the PED requirement for proof testing (3.2.2/7.4)? Paragraph 7.4 of the PED references "for pressure vessels" - is this accurate wording meaning that this will only apply to a vessel designed for containment, or would my pipework still be considered a pressure vessel?

I am in the UK so will be governed by the PED (albeit now PE(S)R).

And before anyone states it, I want to carry out a hydrostatic pressure test regardless given the headache involved in pulling this pipe back out if it fails the service test... just hoping for an understanding of what the code legally requires!

Thanks

 

[XL83NL]

If it’s SEP (art 4.3) under the PED, the essential safety requirements don’t apply and the mentioned point 7.4/7.5 does not need to be satisfied. For this medium I suspect this is SEP. UKCA/PESR currently holds the same approach on categorisation afaik.

Huub
- You never get what you expect, you only get what you inspect.

 

[tommyb96]

Thanks for the response XL83NL.

Just to add on to this as well, I've found some further useful information in PED in paragraph 7 of the scope, where this states " However, this Directive should not apply to the assembly of pressure equipment on the site and under the responsibility of a user who is not the manufacturer, as in the case of industrial installations." which often seems to be the case for pipework.

 

[MortenA]

Compressed air is within the scope of PED (if the pressure is >0.5 barg)

PED art 13 par 1 defines the two groups.

Group 2 is all that is not group 1. Based on the definition of group 1 i would say compressed air is group 2.

Tommy, i think your point of view depends on who you are. There is always somebody who has the responsibility. But the manufactor may not have it if the owner modifies the equipment or builds it into something else (then the owner has the responsibility)

Wrt to testing,i think you should use Table 2 in Annex II

https://eur-lex.europa.eu/legal-content/EN/TXT/?uri=CELEX:32014L0068

So dependig on your pipe diameter and pressure you may have to do more than "check your self".

Im not an expert on the subject so you may want to consult one - but given that your instrumet will walways be build into something else i would assume that the responsibility will be transferred. Just look at table 2 for high pressure or large diameter you might not be covere by article 4 par 3.

Heres a link to a category calculator for what its worth:

https://www.hpivs.ie/ce-certification-2/ped/pressure-vessel-calculator

Best regards, Morten



--- Best regards, Morten Andersen

 

[LittleInch]

We looked into this fairly recently and "interconnecting pipework" is not normally included in PED. However if it is all part of a package, e.g. on a skid, then it usually forms part of the overall package and is inside PED AFAIK.

However in some locations they have decided to move interconnecting pipework into PED, give every piece of pipe a pressure vessel number and then re test it every 7 years. Madness in my view, but if people want to wrap themselves up in knots that's up to them.

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

 

[tommyb96]

Thanks Morten - useful calculator, looks like I'm pretty firmly in at most Category I (Module A) unless we go to a particularly large N.B.

In the interest of SEP I'll hydrotest this regardless but good to have the input into where exactly we fall in the legal requirements associated with the project.

 

[tommyb96]

Interesting point LittleInch - sounds like they're scared of falling foul of any regulations. Agree that it seems overkill but I imagine they're thinking that it's a problem for the next guy to deal with in 7 years time!

 

[MortenA]

@Littleinch,

As i said im not an expert, and i also have difficulties grasping "assembiels" against individual components - and distrubution of responsibility. I wont quothe the entire article 1&2 but...:

Article 1

Scope

1. This Directive shall apply to the design, manufacture and conformity assessment of pressure equipment and assemblies with a maximum allowable pressure PS greater than 0,5 bar.

Article 2

Definitions

"For the purposes of this Directive, the following definitions shall apply:

(1)‘pressure equipment’ means vessels, piping, safety accessories and pressure accessories, including, where applicable, elements attached to pressurised parts, such as flanges, nozzles, couplings, supports, lifting lugs;

(2)‘vessel’ means a housing designed and built to contain fluids under pressure including its direct attachments up to the coupling point connecting it to other equipment; a vessel may be composed of more than one chamber;

(3)‘piping’ means piping components intended for the transport of fluids, when connected together for integration into a pressure system; piping includes in particular a pipe or system of pipes, tubing, fittings, expansion joints, hoses, or other pressure-bearing components as appropriate; heat exchangers consisting of pipes for the purpose of cooling or heating air shall be considered as piping;

So i fail to see hwo "interconnecting pipiwork" is not included in PED? Yes i agree that they are not vessels but nevertheless covered by PED. So your requirements for design and testing may differ from that of a vessel - but its still covered?


--- Best regards, Morten Andersen

 

[LittleInch]

This is the key bit though

"when connected together for integration into a pressure system"
It doesn't actually define a "pressure system", but does define an assembly.

"assemblies’ means several pieces of pressure equipment assembled by a manufacturer to constitute an integrated and functional whole; [my emphasis]

I guess it depends on what the manufacturer is supplying. If they supply all the piping systems made up as spools to bolt together then it may well be classified as part of the overall assembly.

But a separate contractor buying elements of pipe and building them to connect the separate assemblies??

I'm normally looking at pipelines and stations which is also a bit of a gray area when it comes to the boundaries of them.

I think you have to go back to the intent of the regulations which is that manufacturers selling pressure equipment within the EU all conform to the same standards and don't need individual country approval to their own standards. Extending that to the piping which connects different vendor packages or skids together was not the intent of PED, unless it is supplied by the manufacturer and then put together on site.

At least that's the way I've always seen it....

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

 

[MortenA]

@Littleinch,

Right. I think im still uncertain but then again, i wouldnt have to make these decitions myself im just the process engineer (or process safety as it is these days)...



--- Best regards, Morten Andersen

 

[XL83NL]

Just to add on to this as well, I've found some further useful information in PED in paragraph 7 of the scope, where this states " However, this Directive should not apply to the assembly of pressure equipment on the site and under the responsibility of a user who is not the manufacturer, as in the case of industrial installations." which often seems to be the case for pipework.

I don't necessarily agree this sentence provides you a waiver to not CE-mark piping.

We looked into this fairly recently and "interconnecting pipework" is not normally included in PED.

Define interconnecting

However if it is all part of a package, e.g. on a skid, then it usually forms part of the overall package and is inside PED AFAIK.

Agreed, our POV on the legal aspect of the PED as well.

Thanks Morten - useful calculator, looks like I'm pretty firmly in at most Category I (Module A) unless we go to a particularly large N.B.

For assessment of piping, you have to look at the largest diameter that is in your pipe spool or piping isometric line number. Even if that means that 60 welds are 1", and 1 weld is 1.5", that 1.5" defines your category. This is (how unfortunate the impact may be) spelled out in one of the guidelines.



Huub
- You never get what you expect, you only get what you inspect.

 

[tommyb96]

Thanks for the input XL83NL

I think that the paragraph does exactly as you’ve mentioned - this is not to say that the pipe work will not conform to SEP and it will be designed in accordance with a relevant code (ASME B31.3). Given the purpose of the PED is to provide relevant harmonised legislation there unfortunately seems to be some grey areas such as above and it should fall to the responsible owner or owners representative to design/manufacture to a safe standard using recognised codes.

Well aware of the requirement for using the largest bore pipe work when determining category - my earlier point falls into the assembly context before where if I have two separate assemblies operating under the same conditions and one is 1”, the other is 12”, they’ll fall into different categories under PED - this is what I meant by I’m within Category I unless I use relatively large bore pipe work.

Wish I could figure out how to reply to specific quotes on mobile!

 

[LittleInch]

Define interconnecting

Interconnecting for me is when a different party designs, procures and builds the pipe which connects between two or more assemblies or packages.

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

 

[XL83NL]

That’s a fair definition. The point is that the PED doesn’t care about this point, unfortunately

Huub
- You never get what you expect, you only get what you inspect.

 

[LittleInch]

PED is a bit of a work of art alright....

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

 

[XL83NL]

That work of art makes it both interesting, but also difficult at times. We have major issues with package units (compressors, chillers, hoi oil units, scrubber packages, mechanical systems) where reputable companies don’t seem to have the slightest clue about the role the PED has on assemblies, and how it affects their work.
It even gets more frustrating when the MD kicks in (which is most often the case with package units/assemblies), and they come up with a IIB decl. of incorp.

There’s currently work underway to further write out major differences between the PED and B31.3, that will be addressed in a future revision of B31.3, appendix N. It will not make it for the 2022 edt but probably the 2024 edt. if all gets balloted quickly. Thisnahould help overseas (US) users with the CE route, and may hopefully as well help in bridging the gap by creating more understanding.

Huub
- You never get what you expect, you only get what you inspect.