NDT requirements for Valves

[johnthebest]

Hello everyone, as per our project specification
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“Production casting (Body, Bonnet, and Cover) and forging (Body, Bonnet, and Cover) shall be examined in accordance with ASME B16.34 Paragraph 8”.
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Unquote

As per the contractor,
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All valves in this project are conforming to pressure-temperature ratings as specified in project pipe classes. In view of same, these valves will fall under the category of Standard Class Valves as per ASME B16.34.
In addition, NDT requirements including Radiography mentioned in Paragraph 8 of ASME B16.34 are intended for Special Class valves but not for Standard class valves. (Refer ATTACHMENT)
Considering the same, NDT requirements including radiography as mentioned in Paragraph 8 of ASME B16.34 are not applicable to forged valves in this project.

Request Client to confirm the same.

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What are your thoughts?

 

[The Obturator]

Your contractor is not reading the specification right.

I am using ASME B16.34 (2013) Paragraph 8 for reference.

Paragraph 8 SPECIFICALLY states the NDT requirements for SPECIAL VALVES, which includes radiography, surface examination etc.

Your contractor, for whatever reason, has decided to offer STANDARD VALVES and hence making the comments along the lines of "does not apply etc". In other words, his quote to you does not conform to specification.

Your client has stated a specified requirement. Your client wants a spec for special valves. This has not been offered.

Not knowing the full requirement I can't comment further. If that's all this contractor can offer, then if you decide to proceed, you will need to state and sell the deviation to your client for their acceptance.

Personally I suspect your contractor is trying to push his standard line against a "special" requirement whatever that is.

Hope that helps.



Per ISO, only the term Safety Valve is used regardless of application or design.

 

[johnthebest]

Thx for your replies. in the attached, you will find the whole requirement of our projet specification about this point.
require your further judgement and thx in advance

 

[The Obturator]

OK. I might see where your vendor is coming from.

It appears the valves are not exactly "special" but are to be treated as such (by NDT testing to para 8), if they are non standard production or prototype castings.

this is where the specification is vague. Just a change in material or size etc., may constitute a special if it has not been made before.

Best way to approach this, is to advise the client exactly what he is getting (without NDT) and the reasons why;-

We have offered our standard established designs, which are in our normal manufacture, and therefore not specials to be made specifically for your requirements. These are not prototypes. Hence no NDT is offered and the certification that will be supplied is xxx (test/material/conformity certs). Should you specifically require any NDT, then please specify to what items this will apply to advising type of NDT, quantity etc. Please understand that this will no longer be a standard offering and higher costs and longer delivery times will be advised to cover the additional requirements.

Per ISO, only the term Safety Valve is used regardless of application or design.

 

[johnthebest]

there might be a bit of misunderstanding. I represent the client and the contractor is the one who raised this clarification.
The contractor had already made his valve design based on PT rating and judged that the valves fall into the category of standard valves and not special valves. the valves are not made yet.

 

[The Obturator]

Then the contractor is telling you that standard designs have been offered for the reasons I outlined above. It is then up to you, the client, to be satisfied with this.

Per ISO, only the term Safety Valve is used regardless of application or design.

 

[johnthebest]

What I want is that he follow the requirement of the specification. Now my question is: according to the specification, are NDT requirements including radiography applicable to this project or not?

 

[SJones]

Based on the one sentence quoted in the originating post: Yes. The spec requires the stated NDT; it doesn't care whether they are special valves, ordinary valves, fairy dust valves, or any other valve classification that may be dreamt up to avoid doing what has been specified.

Steve Jones
Corrosion Management Consultant

http://www.linkedin.com/in/drstevejones

All answers are personal opinions only and are in no way connected with any employer.

 

[johnthebest]

Thx for your response