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Particular material appraisal

Particular material appraisal

Particular material appraisal

(OP)
Has any one has succes with particular material appraisal, PMA, acc to PED. I'm mostly intrested in US materials as A-105, A-106 grB A-234 WPB etc.

Please share your experiance

JH

RE: Particular material appraisal

There is an official form of the PMA edited by the CEN. Hereafter the content of the form:

Particular Material Appraisal

PMA Ref. No. :
Pressure Equipment Manufacturer :  
Application :
Material Specification :
Thickness Range :
Max. Allowable Pressure :  
Max. Allowable Temperature :
Min. Allowable Temperature :
Design code :

Compliance with Essential Safety Requirements :

Property    Requirement    Compliance    
Appropriate Properties    Allowable stress at 250°C  Rm/20     
Sufficiently Ductile    A%        
Sufficiently Tough    27J at 20°C or lowest operating temp.
Not Significantly Affected by Ageing    At intended operating temperatures    
Suitable for Intended Processing    Machinability Forming Welding
Type of Certificate    Cat. II, III, IV : -3.1.B    
Material Manufacturers Approval    ISO 9000 by Euro. Accredited Body    

Additional testing results are given in Test Report No :

Where selected to be sufficiently chemically resistant to the fluid contained and to avoid significant undesirable effects when the various materials are put together, the named material specification may be used for the construction of the pressure equipment intended for use within the stated limits and subject to the following restrictions :

Restrictions :
Additional Testing :

Signed :                                      Date :  1
    

Approved :                 Date :             Notified Body No.:  
Reviewed    First issue                            
Approved    N.A.                            
I can e-mail it you.
Note that you have to check the material according to the annex I-4. See correspondants guidelines.
For cat. III and IV PMA must be performed by NB.
I did PMA for A-105, A-106 and A-216 WCB.

RE: Particular material appraisal

laphroaig,

Have you contacted your Notified Body? They may have a standard form for this type of thing. We use ASTM materials and have developed PMAs for a number of materials.

Take a close look at the products you're using. For instance, if you're using a metric flange that use on in accordance with EN-1092. Within this standard there are ASTM materials that are considered compliant with the ESRs (see Annex Z).

Fawkes

RE: Particular material appraisal

One point I forgot.

The above PMA form for ASTM A105 shows an impact test value. ASTM A105 isn't impact tested, this would be correct with ASTM A350 LF2.

This is the case with many ASTM materials. Take a look at the guidelines at the ped website (see FAQs). Here you will find a guideline that states impact testing is not required where brittle fracture is not a design requirement.

Fawkes

RE: Particular material appraisal

I am also confused about the materials that can be used in PED vessels.  For example can I use ASTM A 516-70 plate, A-106B pipe, and A-105 flanges?

From what I can see on the PED site, allowable materials must be either:

1. produced to a harmonized standard (of which we have EN 10028, 10213, and 10222 and these, we are warned, may not comply)

2. have received a EAM certificate (of which none of those applied for have yet to be accepted)

3. have received particular approval (for which the guidelines are being prepared)

It looks like a PED vessel is going to be tough to find material for, unless you are in Europe.(question - Have the common ASTM and JIS grades, like those above, been grandfathered" into the harmonized standards?)

Why would anyone (not legally obligated to) want a PED Vessel vs. a B5500 or ASME VIII design?  Is it cheaper? Is it safer?  Can I repair/modify it if I need to? Will the documentation weigh more than the vessel? I guess you can put me in the "wait and see" category for now.

Regards,

Gunnar

RE: Particular material appraisal

gunnarhole,

I think you've misunderstood how the PED works.

The PED outlines how the risk involved in design, manufacture and test of a vessel is managed. To meet this risk you must meet the essential safety requirements (ESR) of Annex 1 (Section 7 of the ESR is not mandatory), the elements of the ESR should be met using a design code such as PD5500 (formally BS5500), ASME VIII Div.1 or the new European code EN 13445.

You can use materials identified in these codes, PD5500 allows ASTM materials (Enquiry case 91) and ASME is now allowing some EN materials. You do not have to use EN materials as long as you provide a PMA. Take a look at EN 1092, European flanges that conform to the PED, the specification allows ASTM materials.

The PMA is specific to the design so I can't offer any more advice than has already been provided.

Regards,

Fawkes

RE: Particular material appraisal

Fawkes,

As you say, perhaps I have misunderstood the intent of the PED.

As an example, let's assume a horizontal API type separator, designed to handle an oil/water/gas mixture at 10 bar and 50 C.  Let's also assume that the materials of construction are ASTM A105/106B/516-70.  Let's also assume it's going to be fabricated in an ASME Code approved shop.

What supplementary documentation would be required by the PED in order to receive approval to use this vessel in Europe.  I mean those documents above and beyond what would be provided for an ASME VIII vessel.  I understand from your previous post that completed PMA's "certifying" that each of the materials selected were appropriate for the design conditions would be required.  What other documents would need to be filed?

I understand that the philosophy of the PED is a noble and wondrous thing.  I just want to know how to buy and use one without employing a consultant from Brussels.

Regards,

Gunnar

RE: Particular material appraisal

(OP)
Fawkes, Gunnarhole

You can use material from almost any code
If you can convince your notified body (NB)that the material fulfil the essential safety requirements (ESR) of Annex 1.The NB makes a PMA.
For the rest of fabrication the notified bodies don't have the same acceptance over Europe. It has been deliverd CE markt vessels, made acc. to ASME, and only ASME! in some memberstates, but I would not think this possible in i.e. Scandinavia.
Unfortunaly you may have to choose "right" NB for your way of fabrication.

RE: Particular material appraisal

laphroig is correct, the choice of notified body is important.

start from the beginning, if you are designing a vessel calculate the total volume upto and including any end connections. Identify the vapour pressure at the maximum design temperature (in this instance 50°C) to help with fluid type selection (liquid or gas).

Identify if the mixture is a group 1 or group 2 fluid.

when you have these details then assess, using tables 1, 2, 3 or 4 as appropriate, if it falls into Article 3 Paragraph 3 or requires CE marking. If it falls into Category I you create the vessel in accordance with Module A and in this instance there isn't any notified body involvement and you assess your own PMAs. Otherwise you need to involve a notified body.

I have designed U-stamped, CE marked vessels and it works that you design the vessel entirely in accordance with ASME (this is necessary for the U-Stamp).

You must still perform a risk or hazard analysis and an essential safety requirement(ESR) checklist. For the ESR checklist reference where each requirement is covered in the technical file used for the U-Stamp. When an element of the ESR isn't covered then you need to address the issue.

Also complete PMAs. If you are completing the vessel with A105, A106 Gr.b and 516 Gr.70 complete PMAs for these materials.

When considering the use of carbon steel it is worth noting that, if brittle fracture is a consideration then section 7 of the ESRs requires a minimum of 27J at MDMT. It may be better to use A350, etc. There is a guidline on the PED web site (see FAQs) that states impact tests are not required if brittle fracture isn't a consideration.

When we write PMAs we address this issue and identify the design parameters for the material and any supplementary requirements placed in the purchase order to ensure the material meets the necessary mechanical and quality requirements.

The additional point to note is that the PED and ASME require different markings so we had to place two nameplates on the vessels.

It is worth knowing where in the world you are. It may be possible that your AI could also be your notified body inspector, this would life a lot easier.

Regards,

Fawkes

RE: Particular material appraisal

The contribution made by abbver98 on Aug 23, 2002 was very helpful. Can someone please send me a copy of the official PMA form. It was mentioned that it was edited by the CEN does anyone know who originated it. Also whether the Notified Bodies have adopted it? Having received a copy of a PMA from one of the major notified bodies prior to Aug 2002 some of this information was missing from their document. However their document included "formability" which seems to have several different definitions.

Michael

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