Designing to ASME VIII & need compliance to PED. 1

[SMacG]

Hi All,

I am relativity new to designing to code (ASME VIII). I have been tasked to design a vessel intended to be sold in both America & Europe.

I therefore have to make sure:

1) The vessel complies to ASME VIII Div. 1 and to be U Stamped (When sold in America).
2) The vessel complies to PED (When sold in Europe).

I intend to design one vessel to meet all these requirements, and get it CE/U Stamped ect. dependant on where it is being sold to. (My company currently designs vessels to both ASME, and to PED. However we have no experience in designing one vessel to meet both requirements)

The broad outlines of the design requirements have been defined in terms of capacity, max. temp & pressure.

I was wondering if someone could highlight the main issues when designings to comply with both the code & directive?

My initial concerns are material compliance, hydro test pressures ect.? I understand it is possible to incorporate both requirements into one design, dependant on paperwork ect., is there any experience of issues and restraints in doing so? Cheers in advance!

Samuel

 

[jwhit]

I think the first thing you need to do is determine which PED Category the vessel will fall into, keeping in mind that the rules get tougher with higher category. I'm not involved in design, but, so far the biggest issue I have found is that as an American material manufacturer it seems to be difficult to get straight answers on how to go about getting the needed qualifications in place. What it seems to come down to is deciphering which parts of the EN/ISO standards have to be applied in addition to the ASME code requirements. Everything is based on equivalency to the European standards. You will need to find a good third party European based RTPO or NOBO to work with. I have found that they will help to guide you once you have signed on with them. Hope this is a little help to you.

 

[fegenbush]

jwhit,

While I agree that the RTPO or NOBO will be of great assistance in the process, I do not believe it to be necessary for them to be European based. The first vessel that I did that was PED compliant, we hired a very expensive RTPO and went through several revisions due to their inexperience with our process. After that, I learned that our normal AI was qualified to perform those activities. It would have saved us considerable time and money had we known that at the beginning of the job.

 

[XL83NL]

There are several good topics on this at engtips. Furthermore, ASME has published a PED guide once I think, that discussies the main differences.

In short, here are the main issues to address. These main issues are all due to the Essential Safety Requirements (ESRs), that typically come in place when your category is I or higher. You need to review the PED yourself to get a good overview, as there are other important aspects that may or may not be covered by ASME.

Depending on your category, WPQ and PQRs need to be third party certified. That means a nobo or RTPO needs to certify the welders and the procedures.
You can fullY apply ASME design rules, and ASME IX, BUT materials need to comply to the ESRs, meaning youll have to make a PMA for each material. An example PMA can be found on Lloyd's website, which is useful as a template.
Noach toughness issues become a design aspect in the PED at 20 C and below, I think, so impact testing may be requird. There are some exceptions for aust. materials though, covered in the PED guidelines.
Safeguarding is something you might want to review. PED saus the momentary pressure surge for vessels shall be less than 10% of the max allowable pressure.
Materialcertificates and traceability need to be kept in place.
There's a minimum test pressure (but ASMEs is usually higher)
Third party approved NDE personeel for certain categories
CE marking

All n all, it took me some years to get it all in place. One useful doc that assisted me in that are the PED guidelines, which are kind of interpretations that detail a lof of things for which the PED is too vague.

Good luck and success. Let me know if I can be of any further help.

 

[SMacG]

Hi guys,

Some really good replies! I had not previously known about the ASME guide to PED compliance. I will look into it and see if we have or can obtain a copy!

I believe the vessel is Cat. 1, however this is yet to be confirmed due to the infancy of the project. [I am just trying to plan ahead and foresee any major issues.]

By the sounds of things I need to study the ESRs applicable to a Cat. 1 vessel to see what aspects are not included within the ASME scope.

Unfortunately I am relativity new to the industry (9 months), I have successfully bought to manufacture a small number of ASME coded vessels. I will however be the first to admit I don't have the strongest understanding of the code. I am therefore worried with the incorporation of both PED & ASME.

It is slightly disconcerting to hear it took you years to get it all in place! Thank you all for the initial pointers.

 

[XL83NL]

Within few months or weeks, you'll have the basics figured out. The details, and interpretation of the (almost political) wording requires a lot of rereading and experience, which caused me to take years to master it to the level I now have. I still learn everyday from the PED though

 

[DekDee]

SMacG,
XL83NL gives sound advice regarding the PED.
I had the misfortune to be exposed to it when I worked on the construction of a US$5 billion Nickel Refinery in New Caledonia (a French territory/island).
I sincerely hope I never have to have anything to do with it again - IMHO an absolute nightmare,
Cheers,
DD

 

[OSIRIS7]

PED, Guidelines and PMA's:
[URL unfurl="true"]http://ec.europa.eu/enterprise/sectors/pressure-and-gas/documents/ped/index_en.htm
[/url]

PED category selector and flowchart:

http://www.lr.org/compliance/directives/171816-pressure-equipment-directive.aspx

Link


Also have to comply to country specific requirements:

http://ec.europa.eu/enterprise/sectors/pressure-and-gas/pressure-equipment/memberstates_en.htm

Link
Unless of course you are able to eliminate risks in a risk analysis (do this risk analysis BEFORE a project! It will most probably save you expenses and some head aches).

 

[jwhit]

fegenbush,
Particular material appraisals, NDE personnel qualifications that take SNT-TC-1A personnel and classify them as equivalent to EN9712 must be done by a European addressed organization (Lloyds, BV, TUV etc). The same holds true of welding procedures. NDE personnel must be approved if you are making Category III of IV vessels, and welding approval applies to Cat. II, III and IV vessels. If you are working to sound engineering practice it is not as restrictive. An AI is not authorized to do those approvals. I'm going through it right now and agree with DEKDEE, it is certainly no fun, you get run in circles trying to find the answers and even the people that know the answers aren't totally certain in many cases. Determining the need for the qualifications is one of the simpler tasks, but they make it difficult to actually accomplish it.

 

[BigTank]

We are going through the qualification of a standing design to PED compliance. As is alluded to (and explicitly stated), applying CE certification isn't a linear thing. We hired a TUV Rheinland to get us through the process.

As it turns out, we will be certifying our exchangers onesy-twosy as we build them through an inspection similar to the A.I.'s final hydro witness, qualification of the welders working on the unit, a 'design review' and PED-required safety-related documentation, and PED-qualified material sourcing. It's a simple process, but I get the feeling one simply can't accomplish it successfully and with concision without someone holding their hand.

--------------------------------
Fitter, happier, more productive

 

[fegenbush]

jwhit,

From the HSB Global webpage:

"Through our relationship with HSB GS Europe, we are able to offer Notified Body services to those manufacturers shipping vessels to the EEA."

Please advise as to whether this satisfies the requirement you presented in your post.

 

[jwhit]

Fegenbush,
Our customers have told us that for anything more than SEP, use of HSB is not acceptable as they are not universally recognized. Also, I don't believe they are able to do the NDT equivalency.

 

[ARHeit]

I think everything I could suggest has come up except for one item: double check your material specifications. We were using ASME to calculate material thicknesses using the ASME high stress values for material at elevated temperatures from ASME Sec. II, when going through the process of filing PMAs and design considerations we found out that the GmbH only accepts ASME low stress values for materials at elevated temperatures. We were making T-304 and T-316 stainless steam jacketed cookers, for that material the differences were enough to need the next larger plate thickness. Caused a lot of headache. We even looked up stress values published for European material suppliers/certifications and they were lower than ASME's, but if you have a U-stamp using ASME design they won't listen.

Can't remember all the circumstances and maybe with different materials it won't matter as much. But it's worth considering before you order material.

"Whether you think you can or think you can't - you're right." - Henry Ford

http://www.eng-tips.com/faqs.cfm?fid=376

 

[OSIRIS7]

only accepts ASME low stress values for materials at elevated temperatures.

To which table are you refering? ASME II part D table Y-1? Just out of curiosity.

 

[ARHeit]

I don't have a copy of the code books currently, but that looks correct from memory. Some material specs are listed twice but have different values. I've heard these referred to as the high and low values.

Found this related discussion:

http://www.eng-tips.com/viewthread.cfm?qid=318287

"Whether you think you can or think you can't - you're right." - Henry Ford

http://www.eng-tips.com/faqs.cfm?fid=376

 

[DekDee]

jwhit,
That is interesting - if by HSB you mean Hartford Steam & Boiler, they were the NoBo for a lot of our pressure vessels fabricated in Malaysia, Korea and India.
We had one guy on the project(a very knowledgeable engineer) whose sole role was ensuring interpretaion of and compliance with the PED.
Cheers,
DD

 

[XL83NL]

GmbH only accepts ASME low stress values for materials at elevated temperatures

They must have a reason for this which should be based on the PED.

Im currently reviewing a vessel for operation in the creep regime, designed acc VIII-1, compliance with PED 97/23/EC. PMA's are required (Cat. IV), hence NoBo needs to sign the PMA.
From which paragraph of the Essential Safety Requirements does it follow only low stress values from ASME may be used?

 

[ARHeit]

In PED 97/23/EC Annex 1 7.1.1 it says that the yield limit should be a 1.0% proof strength for austenitic steels. The values from ASME II table Y-1 are 2.0% calculated values. The europeans told us that as a saftey factor they have only ever accepted the low values for the reasons that they are calculated, not measured values, and they are 2.0% instead of 1.0%. We talked to them for a full week about how a 2% value would be more accurate. We looked up the values of comparable metal numbers (there is no T-304 or T-316 in their charts, but you can find materials with VERY similar chemistry) and their values were HIGHER than the ASME high values. I wish there was a point in this discussion where I could see there point...but as we kept digging it just seemed more and more arbitrary.

During that time I produced an excel spreedsheet comparing the materials yeild, Rm, Rm/t, and so on. I'll try to find it and maybe that could clarify some of the issues. But above is the discussion that we had with the French GmbH who wouldn't accept the design. They told us that for some T&SHE there is some loop hole to all this, but we were making steam jacketed kettles, and that may have been part of the issue. ASME VIII doesn't speak directly to jacketed kettles, you have to do a fair amount of interpreting. But we always got through it with ASME. Our NoBo AI said he agreed with us, but the European body has to sign the documents.

"Whether you think you can or think you can't - you're right." - Henry Ford

http://www.eng-tips.com/faqs.cfm?fid=376

 

[jwhit]

DEKDEE,
Yes it is the same HSB. I honestly don't know the entire reason behind it other than it had to do with certain countries(outside the EN)not accepting them, it may not be fully PED related in fact. I will find out more in the next couple of weeks. It was darn inconvenient for us to be told not to use them since our PED cert per 4.3 Annex 1 is through HSB.
We're a material manufacturer rather than a PV manufacturer, but are going through procedure and personnel approval for Cat II to IV per a customers request. It has been a long complicated path with a lot of wild goose chases and lack of help/co-operation while trying to get answers as to how to proceed.

 

[XL83NL]

ARheit, thank you for clearing that up. Clear. However, Im not sure how this 1%/2%-thing is related (only) to creep, as para 7.1.1 of PED doesn't refer to creep ion general.
I must be missing something - or its just he Monday morning start-up.