Double material certification EU

[JVT_Stress]

Hello,

I'm working for an EPC contrcator based in Europe and we design and construct piping according to PED and EN13480 code requirements.
Besides my job as a pipe stress engineer, and i'm also tasked with setting up the piping specifications for our projects.

When we request a quotation for piping components, we notice a trend that our typical material suppliers are offering more and more "double or triple certified material" EN/ASME/API?

Example:

When we request welded pipe according to:
EN10217-5 P235GH DN900 (32") 914mmx8mm.

we get offered a welded pipe according (double certified):
API5L grade B/P265GH TC1 acc EN10217-5 with dimensions 914mmx9,5mm?

So for the material part I have no issues, because if it's double certified it conforms to our request EN10217-5.
But on the dimensions I have serious doubts, because I think the tolerances between API5L and EN10217-5 are very different?

The same goes for fittings:

If we request fitting
EN10253-2 P235GH ELBOW 3D DN150 (6") wall thickness series 2 (WT=4,5mm) type A

we get ANSI B16.9 ASTM A/SA234 WPB & EN10253-2 P265GH certified with dimensions 6"xSTD?

Which to my opinion is not acceptable?

Does anyone on this forum has the same expierinace with material suppliers?
How do you deal with this double or triple EN/ASME/API certification?
Because if I insist that the material supplier must be conform to our material and piping specification the price and delivery time of these piping components goes up. With a frustrated PM as a consequense.

Best regards,

 

[XL83NL]

Direct experience? No.
I have done some projects on EN 13480. Iy you review my older posts, you might find my experience on there.

There may be multiple answers to your question/issue, but I think one main reason could be supply & demand. Mills offers that what's demanded most, and try to sell that with minimal extra fabrication steps/effort. hence the multiple certifications. I have seen the same quadruple cert on 316/316L/1.4404/1.4401 to both A312 and EN 10216-5. Im not 100% sure if both have sufficient overlap but you may assume that, apart from historical demands for A312 TP316, mills now also get requests for EN 10216-5 1.4401/1.4404, and tru to look for ways to produce such pipe within 1 lot or batch. That way of certying material, in essence, is perfectly fine.

Now, related to your issue, what happens to be the issue is the addition of a dimensional standard, e.g. B16.9. Since you need to deal with EN 13480, the most straightforward way of code compliance is to use (annoying) fittings to EN 10253-x. Those have their own ratings, albeit in a very awkward way (A & B route), that conform to the requirements of EN 13480. Not meeting those requirements, I think, takes away the presumed conformity to comply with the design code, and thus with the PED. If you need 100% EN 13480 conformity, you'd have to recalculate that B16.9 A234 WPB/EN10253-2 P265GH fitting, using EN 13480 formulae, and B16.9. But that's where it gets tricky since B16.9 doesn't list all required dimensions you need for that EN 13480 formula. In practice, I would just tell the NoBo (in advance) what your issue is, and how you dealt with it. I would assume that the elbow is equally strong as the pipe its connected to, provided the OD and ID are the same (thus same wall), since that's how B31.3 does it.

Next time, I'd stay away from EN 13480 design. I have, and experienced from personal work, a lot of these issues with that Code on this forum. EN 13480 can be used with little issues provided the wall thickness is very small (so low-pressure stuff), in only a few common materials. Once you deviate from that principle, EN 13480 gets difficult to use, and expensive, since very few mills and stockits will provide you with what you exactly need in terms of materials and fittings. The market simply doesn't seem to be able to provide code-compliant EN 13480 materials, since the demand just isnt that high. Thats why, I guess, they made this fitting also ASTM & ASME compliant so they have some 'assurance' of selling it.

Whats your application in terms of service/medium, pressure, temperature? PED Category?

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

 

[JVT_Stress]

Hello XL83NL,

Thank you very much for your reply.

To answer your question conserning application :
We design and build complete (steam cycle) power plants up to 100MW max mainly in Europe. The piping ranges from main steam piping CAT III (ex: DN350 (14") 68Barg 450°C) to large bore >2m (78") LP steam ducts to small utility piping Art4.3 (SEP). We are PED manufacturer for piping (Cat III mod H certified) and also for complete assemblies (PED Cat IV).
The codes we use for piping is 90% of the projects according to EN13480 and 10% of the projects according to ASME B31.1

Concerning your remark "to use (annoying) fittings to EN 10253-x",
->I understand your point of view from an ASME piping code vieuwpoint. Those type A & B fittings are a heritage from the old DIN standards in Germany, that are now harmonised for every member state in the EU by means of EN 10253-x standards. It's just another design philosophy where I have no issues with as long as we are consistent and do not mix those 2 ASME/EN design philosophies. But if this is marklet driven we are left in the dark, and can only conclude that the intention of the PED is realy good, but it does not play out in reality.

"If you need 100% EN 13480 conformity, you'd have to recalculate that B16.9 A234 WPB/EN10253-2 P265GH fitting, using EN 13480 formulae, and B16.9. But that's where it gets tricky since B16.9 doesn't list all required dimensions you need for that EN 13480 formula."
-> Correct I can confirm this, this takes away presumption of conformity because we do not follow a harmonized standard, but PED does not restrict this. It is allowed as long as we can proof that a same level of safety is guaranteed. But as you stated this is not possible because we do not know the exact dimensions of an ASME B16.9 BW TEE to re-calculate according EN13480/EN10253. Thats where it becomes messy.

Unfortunalty I cannot stay away from design according EN13480:
-we have sucessfully build power plants according to this code, with the correct harmonized fittings. (as stated 68Barg 450°C design condition) this plant has operated for almost 10 years without problems.
-our clients sometimes request that their new plant is build according to EN13480. Or that their existing DIN plant shall be modified with EN13480.

As you stated :
"The market simply doesn't seem to be able to provide code-compliant EN 13480 materials, since the demand just isnt that high. Thats why, I guess, they made this fitting also ASTM & ASME compliant so they have some 'assurance' of selling it."
-> I agree
-> It's also in some sence a political issue, the sectors where our clients are situated want to keep things the European way. The more EN13480 and EN piping components are to be used in Europe, the lower the price and improves the availability of those components. Thats what I have heard 20 years ago aswell, when PED was introduced as a law in Europe.

So the only thing I can do is keep pushing for EN10253 fittings and keep with EN13480 design code, and to be consitent PED essential safety requirements.
I need to compare the additional cost of the material, with the additional engineering cost or recacluating everything twice depending on what is availableon the market.

Best regards,

 

[EdStainless]

The PED is a political system, it was designed for restraint of trade, period.
So you pay for that in time and money.
I have had customers beg me to make tubing to EN specs, but I simply can't work to some of those specs. They tell me that buying from the traditional supplier will cost 30-100% more and take twice as long.

= = = = = = = = = = = = = = = = = = = =
P.E. Metallurgy, consulting work welcomed

 

[XL83NL]

Concerning your remark "to use (annoying) fittings to EN 10253-x", smile
->I understand your point of view from an ASME piping code viewpoint. Those type A & B fittings are a heritage from the old DIN standards in Germany, that are now harmonized for every member state in the EU by means of EN 10253-x standards. It's just another design philosophy where I have no issues with as long as we are consistent and do not mix those 2 ASME/EN design philosophies. But if this is market driven we are left in the dark, and can only conclude that the intention of the PED is really good, but it does not play out in reality.

My experience so far with EN 10253 is that getting the right fittings is quite tricky, esp. for type B. I do agree it's not good to mix up EN and ASME, but in some cases, you have little choice. We have done a lot of projects with piping where the client required EN/PN-rated flanges, which we used under a B31.3 design, with ASTM materials and ASME design, NDE, testing, etc. Simply because in the end, the total cost of the piping systems was something the client did want to pay for. An all-compliant EN 13480 piping system would've been too expensive.

PED intention is good, but quite often doesn't turn out to be cost-efficient. There's also a lot of misconception at users and NoBo's, very often resulting in strange requirements that are impractical to meet.

I guess that's what Ed is also pointing at, although I don't fully agree with him.

The PED is a political system, it was designed for restraint of trade, period.
So you pay for that in time and money.

CE-marking has provided a lot of benefits, it's just that some parties (NoBo's) included make ridiculous requirements on top of the PED, and simply make it part of the PED where i fact it really isnt. I have that experience esp. with a few German NoBo's

"If you need 100% EN 13480 conformity, you'd have to recalculate that B16.9 A234 WPB/EN10253-2 P265GH fitting, using EN 13480 formulae, and B16.9. But that's where it gets tricky since B16.9 doesn't list all required dimensions you need for that EN 13480 formula."
-> Correct I can confirm this, this takes away presumption of conformity because we do not follow a harmonized standard, but PED does not restrict this. It is allowed as long as we can proof that a same level of safety is guaranteed. But as you stated this is not possible because we do not know the exact dimensions of an ASME B16.9 BW TEE to re-calculate according EN13480/EN10253. Thats where it becomes messy.

I would say that if such a B16.9 fitting is both ASTM and EN certified, you'd have little issue. Use EN material stresses, and simple apply the B31.3 method where a fitting of sml construction is equally strong as pipe. So, the fitting has the same rating as EN pipe, calculated with the EN 13480 formula for pipe. AFAIK, there's nothing in the PED which doesn't allow you to do so. By doing so, you make use of a worldwide recognized and applied code with dozens of years of successful practice & service.

As you stated :
"The market simply doesn't seem to be able to provide code-compliant EN 13480 materials, since the demand just isnt that high. Thats why, I guess, they made this fitting also ASTM & ASME compliant so they have some 'assurance' of selling it."
-> I agree
-> It's also in some sence a political issue, the sectors where our clients are situated want to keep things the European way. The more EN13480 and EN piping components are to be used in Europe, the lower the price and improves the availability of those components. Thats what I have heard 20 years ago aswell, when PED was introduced as a law in Europe.

Agreed, but after some 20 yrs in which the code now exists, so little benefit is noticable. Even for the most straight forward materials like A106B or 316, in EN grades, we have found so many issues. You in your own, together with a few others, will not make that things will change significantly in say 10 yrs, I suspect. Ive seen some reports from CEN on the application of EN vs ASME for European plants. They make it look very attractive, but those reports give a different view of the current real market. As long as you have low pressures (say up to PN16), youre moderately OK, provided you have simple materials like P235 or 1.4404. Anything besides that becomes difficult.

@ JVT_Stress; where are you from? Which suppliers do you have for piping materials and fittings?

PS: on a side note, what I do like about the EN codes (both 13480 and 13445), is that theyre requirements for NDE are very clear, simple to understand, and easy to check on delivered equipment and NDE reports for code compliance.

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