ASME V is no good! 2

[deco0404]

The job we are currently working on is a 60ft tower which will sit on top of a new building. 20ft approx is made from Carbon steel, this section will be anchored inside the building. The welding process is SAW. The remaining 40ft is above the building and is manufactured from 2205 duplex using a combination of GTAW & GMAW. The tower is approx 1.5M diameter at the bottom tapering up to 300mm at the top.The W.T. is 15mm all the way up. All the procedures & wqt's were accepted by third party inspectors.

Our client has insisted that the tower be built using the NSSS ( National Structural Steel Specification ) with the following provisions.

Radiographic examinations _*TO*_ be carried out to ASME V Article 2.
Radiographs to be assessed using BS EN ISO5817 level 'C'-2007.

That is our clients instruction to us, two lines with big full stops at the end of each. The wording may not be entirely accurate as I am doing this from home and don't have the file in front of me, I have highlighted the word to, as this is a key point which will become clearer as I go on.

A couple of weeks ago we started doing trial radiographs and found that at a particular Kv, Ma and distance setting we could achieve the proper density ( averaging about 2.5 in parent material ) & sensitivity (averaging about 1.3%), using D7 film with 0.125mmPb screens front & back. This is well inside any boundaries set by ASME V.

Along comes the third party inspector............

Now they say that unless you use D5 film we are going to reject all 200ish films so far.......................

Their reasoning is as follows. In order to comply with the requirements of EN5817, which does not address the method of detecting defects, we must then consult ISO17635, which contains a correlation between the quality levels and acceptance levels for different NDT methods. This spec then says we must carry out our Radiography in line with EN1435.

Now here as you can imagine the fun started................

We maintain that as our client specifically asked for ASME V, and that we can produce radiographs that meet that spec, our only concern in using EN5817 is whether or not the welds are good or not. If we change our rad system to EN1435 then we are not in compliance with our clients request and scope of work, we also maintain that ASME V DOES give quality levels.

The third parties contention is that in order to use EN5817 we need to use EN1435 as well and that even though we meet the requirements of ASME V, all the films are rejectable because we don't comply with EN1435, and they are not prepared to budge on that.

As I said earlier this is not a nuclear sub we are building, and clear heads will probably prevail eventually ( we could ask the client if it would be more appropriate to use ASME VIII as acceptance criteria, but don't want to concede an inch just yet). Apart from the financial implications, there are very good lessons to be learned from this, but in the meantime if anyone can offer any kind of assistance on who if anyone is right or wrong, or if there is a standard from which we can correlate the two I would greatly appreciate it

Declan

 

[TVP]

Declan,

Your third party inspector sounds like a complete tool, and is apparently does not understand the proper usage of consensus standards (ISO, ASME, etc.). First, ISO 17635 is NOT a requirement for ISO 5817! The following is an excerpt from ISO 5817:
[navy]
2 Normative references
The following referenced documents are indispensable for the application of this document. For dated references,
only the edition cited applies. For undated references, the latest edition of the referenced document (including any
amendments) applies.

ISO 2553:1992, Welded, brazed and soldered joints — Symbolic representation on drawings
ISO 4063:1998, Welding and allied processes — Nomenclature of processes and reference numbers
ISO 6520-1:1998, Welding and allied processes — Classification of geometric imperfections in metallic materials —
Part 1: Fusion welding[/navy]

Notice that ISO 17635 is not included here; it only appears in the Introduction and in the Bibliography. This means it is not a requirement, and therefore only for reference purposes. ISO 5817 is a good standard for analysis of weld defects, and has been standardized in the European system as well (BSI, DIN, AFNOR, etc.), which is probably why your customer is specifying its use. Your procedure appears to be appropriate and meets the drawing specification that you outlined in your original post. It is possible that your third party inspector is not very knowledgeable about welding and use of standards, and is therefore trying to rigidly apply what appears in the standard, even when it is incorrect or misguided.

 

[JR97]

Declan,

My two cents worth is that your position is more correct than the third party inspector.

I can identify with your dilemna. The root cause of the problem is the customer not specifing a uniform approach to the radiography. Although I am not familar with the EN specs you are dealing with, most families of specifications are made to be applied together; e.g. ASME Code Section VIII with ASME Code Section V, MIL-STD-278 with MIL-STD-271, etc. When a customer picks parts from different families confusion reigns.

Ultimately the answer to your questions will have to come from your customer, not the third party inspector. Unfortunately, your customer probably does not have much experience or expertise with NDE specifications - at least that has been my experience.

If you want to try to play wordsmithing with the third party inspector - as you wrote the requirements in your post; the radiographs are only to be ASSESSED in accordance with EN ISO5817. That implies the radiogaphs are to be generated IAW ASME Section V, which allows D7 film provided the requried IQI is visible.

Good luck.

JR97

 

[deco0404]

Thanks for your input guys, very helpful. TVP hits the nail on the head, we actually got clarification from TWI & BSI on this issue as well. We also got the following.

ISO Directive Part 2, 'Rules for the structure and drafting of
International Standards' clause 6.1.4. states that 'the Introduction is an optional preliminary element used to give specific information or commentary about the technical content of the document. It shall not contain requirements.

Good lessons to be learned here, as I was not familiar with the above..........

Declan