reference of standard on drawing 1

[waqasmalik]

Hi friends,I have a question regarding the mentioning of two different standards on drawing,one for welding and other for inspection. I received a drawing from the defense industry they were referring one military standard for welding but on the same drawing it was noted that inspection shall be done according to other mil standard.

Is this possible? Should'nt there be uniformity in the application of standards?

Thankyou

 

[Duwe6]

Not that unusual; first spec is "how to weld it" and second is "how ti inspect it".

 

[waqasmalik]

But at the last pages of first spec there is mentioned the acceptance criteria.Should'nt we refer the inspection criteria of the same standard which is being referred for welding? Actually they are conflicting thats why it confuses me, its a class three weld, first spec says there will be no Radiography but second spec says there will be radiography

 

[Duwe6]

The second spec has been invoked by the dwg, so it is mandatory.

 

[BUGGAR]

No, Specifications typically govern over the drawings. Or is there a specified Order of Precedence that places the drawings first?

See why it is so important to do the specs right? It's O.K. to combine them like that but modify them as required to not contradict each other. We frequently combine AWS and API but VERY carefully. The Order of Precedence will cover a few misses but it is still a crutch.

 

[tbuelna]

I agree with Duwe6. The component must conform to all requirements listed in the drawing notes. Based on your description, the NDI requirement in the second note is supplementary to the inspection requirements listed in the process spec of the first note. What the drawing asks for is a class 3 weld that gets a radiographic inspection.

You did not note what MIL-Specs were called out on the drawing. Typically, in addition to a weld spec and a NDI spec, there should also be a standard called out for NDI accept/reject criteria.

 

[waqasmalik]

Welding spec is Mil 22248-A and inspection spec is Mil 2035. If the weldment is made by using the parameters in 22248-A, why it needs to be inspected on Mil 2035, its not been welded using the parameters of 2035. 22248 says for class 3 weld there will be no RT, 2035 says that for class 3 weld there will be RT

 

[Ron]

BUGGAR....I disagree. Neither takes precedence. They are both contractual obligations. Unless there is a statement in the contract giving an order of precedence, a discrepancy between the two is simply a conflict that requires resolution, usually through an RFI.

As for referencing a separate inspection standard, as others have stated, that is not unusual. If the acceptance criteria are given in the welding standard, then the inspection protocol should address that. If there is a conflict between the acceptance criteria in the two different standards, then issue a request for information and let the design professional of record make the call (in writing of course!).

 

[gtaw]

MIL-STD-2035 is the acceptance criteria for VT and other NDE methods. It is used when referenced by the fabrication document such as NAVSEA S9074-AR-GIB-010/278 or a different fabrication standard or the customer's drawings.

All military fabrication documents include a provision stating the hierarchy or precedence of the other documents. Generally, there is an upper tier document that addresses the general requirements of construction. That document references other working documents such different NAVSEA documents for qualifying the welding process, a fabrication document for actual fabrication requirements, a different working document for acceptance criteria, and a standard for qualifying inspection personnel. Also referenced are various material standards, painting standards, standards for properly marking items, cleaning standards, packing standards, etc. All of these requirements can be modified by the customer (Government agency. Such modifications, i.e., exceptions, additional requirements, material substitutions, etc. are usually noted in the project specifications or purchase order. Generally, the construction drawings are reviewed and approved by the customer. Exceptions taken by the contractor/fabricator are suppose to be noted during the submission process. All exception or modifications to the contract documents are supported by letters of approval. Those letters are noted on the approved drawings so that anyone reviewing the drawings at a latter time understands the modifications have been noted and approved by the client. The bottom line is the approved drawing and approved bill of materials becomes the "Bible" for the purposes of construction.

Best regards - Al

 

[weldstan]

When specification requirements conflict, an RFI should be generated to the Purchaser to provide clarification.
Governing specifications can be defined on a drawing or within an overarching Engineering Specification or a Contract Document within the Purchase Order.

 

[ewh]

I don't see the discrepancy. One note directs which spec to follow for welding and another directs which spec to use for inspection. It does not matter if both specs include sections for welding and inspection, the drawing directs which specs are to be used for which particular function.

"Know the rules well, so you can break them effectively."
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