MSS-SP 72 vs. B16.34 2

[Mous1747]

Not sure why the customer wants the valve to be per MSS-SP-72 rather than B16.34 ?
would anybody know what could be the reason?

 

[Danlap]

Given your general question, then I can only imagine general multiple-choice answer
a. MSS-SP-72 define port sizes for ball valve smaller than 24” for both full bore and reduce bore. I believe this is not covered by ASME 16.34 solely. Thus, customer maybe requires an exact Cv or pressure drop requirement as like to like replacement
b. “Customer always right” mindset
c. This is replacement of existing old valve>designed/selected as per MSS-SP-72 > thus replacement with other standard requires Management of Change (MOC)> thus not desirable by customer
d. Critical safety related valve, thus any changes will involve government official approval>thus not desirable by customer
e. Customer do not have the capability to assess the gap between MSS-SP-72 and ASME 16.34. this is quite common if the purchase order driven by procurement without engineering consultancy
f. etc.

Sometimes the practical solution is for the PO awardee to assess the gap of their existing stock valve (let say as per ASME 16.34) and issue a declaration of conformity that it is also adhering MSS-SP-72

Kind regards,
MR

https://nosuchvalve.com

All valves will last for years, except the ones that were poorly manufactured; are still wrongly operated and or were wrongly selected

http://www.eng-tips.com/faqs.cfm?&rat1=2&fid=376

 

[Mous1747]

i did go through every section of the MSS-SP-72 from section 1: scope till section 7: testing, and compared to 6D.
i found that 6D is equal or better than MSS-SP-72. so basically if the valve is meeting 6D then it meets MSS-SP-72