Referencing Different Editions of the Same Book

[GrimesFrank]

Pretext:
This is all within the realm of ASME Sec III ND (CED 1974)

I have a manufacturer providing me with a design report for a replacement valve. I have asked a couple seniors in my group for advice and want other opinions.
The valve designer is using B16.5-1968 to establish P-T ratings, as '74 ND references B16.5-68...fine. Thereafter the designer is using a later edition of B16.5 ('73 possibly) for his thickness calculations. Is it acceptable to mix-and-match reference editions to suit your needs? He chooses B16.5-68 because it allows him to stay at CL 1500 (2400 psi @ 200ºF) for F316L, whereas B16.5-73 would force you to CL 2500. And just to add to the confusion B16.5-2003 would allow CL 1500 as well.

This may seem like a trivial/semantical question but it has me scratching my head on when I do design, can I go just pick another year if I don't like the answer I get from one edition?

 

[JLSeagull]

Wow! ASTM B16.5-1968 is Very obsolete. Many things changed in the 1970's. The pressure and temperature limits vary by material groups.

You must use current standards. My copy of ASME B16.5-2003. The previous revision was B16.5 1996.

 

[GrimesFrank]

JL,
In CSA N285.0 land, if you are providing a "replacement" component and not "designing" you may use the code of construction as your guide, hence the B16.5-68 stone tablet. I have no problem with that per se, I have a problem with the mix/match approach.

From a safety point of view I like the valve, its the "back of envelope" look to a Nuclear Class design report that is concerning.

Maybe this is all much ado.... but as a fledgling code designer I have a problem with the confidence to tell other professionals I don't agree, unless I have a mountain of evidence behind me. Time and experience will come I guess.

 

[GregLamberson]

The only caveat is, at least in my industry (oil & gas projects) on retro-grade projects, there are 2 options: 1) one can use the code that was in effect at the time of installation or 2) the latest code, but nothing in-between, i.e. you must choose one or the other, no cherry picking.

Greg Lamberson, BS, MBA
Consultant - Upstream Energy

Website:

http://www.oil-gas-consulting.com

 

[GrimesFrank]

Greg,
As was my assumption when I started in this industry but lately I see colleagues/contractors/vendors taking some different interpretations and stating they "meet the code". Now that its my ink on the line I would like to be clear on this subject in case ass_u_m_ptions do what they tend towards down the line.

 

[JohnBreen]

Well, the nuclear industry is quite different. You must use the Code documents that are spelled out in the current FSAR. I am working on a USA plant that was designed to the draft of B31.7 and B31.1. The current (approved by the NRC) FSAR specifies ASME III, 1974 as the "Code of Record" for replacement (and analysis) of piping associated with reactor head replacement.

If you ever get it figured out, they will change the rules.

Regards, John.

 

[GrimesFrank]

John,
I don't know what a FSAR is, sorry, but in the Cdn Nuke industry, there is an allowance for you to use the "code of record" or later.
Talking to my seniors here they say as long as the vendor can explicitly justify why its appropriate to reference different years of the same book for their design (i.e. safety-wise) then it can be done. I guess as with anything so long as you analyze/justify to the hilt you can do pretty much anything.....within reason.

 

[JLSeagull]

This is not really a question is it Frank Grimes? You already know the answer that you want and now you wish to support that answer.

For instrumentation and control systems it would be difficult and impractical to replace anything "in-kind". The technology moves to rapidly. If I replace a level transmitter I would not buy the same caged displacer with a pneumatic output. I might buy a similar external caged instrument with a magnetic level indicator and guided wave radar or magnetostrictive transmitter. If I worked at a plant and the vessel flanges were A 150 Class 600 RF I would likely specified the same connection. However, I am not in maintenance, I am in engineering. I would only be replacing the transmitter as part of a plant modification. Thus, I would at least comply with the codes and standards that were current at the time of the contract execution (perhaps the latest codes even if changes occured after the contract was signed).

In addition to other instrumentation I buy control valves, shutdown valves, safety relief valves, etc. I would buy a valve to comply with the current design standards for a plant modification project. I have a real example that is similar to your preference to match the existing flanges. A flangeless WCB through-bolted ball-style control valve in a bypass around a reboiler - rated Class 150. The design pressure and PSV setpoint were 290 psig. The line had been reclassified Class 300 during a prior modification project. I bought a new control valve inline with the reboilder as Class 300. I did not bother the existing valve. However, if I had to do any modification to the existing valve I would have replaced it with a Class 300 rated valve. Also, it would have required at least a lugged body as it was in hydrocarbon service.

A little additional safety is much less costly than the additional liability of failing to maintain the current design requirements.

 

[GrimesFrank]

Thanks All,

My "quick" solution to this, so I could stop debating with the vendor and get a product going, is I did the report myself, sent it to them and said review & incorporate into report.

They agreed.

*Dusts hands* All done.

 

[pvesseleng]

Hi,
You can not use latest or another edition which are not referenced on your construction code edition.

 

[GenB]

I think that you are locked to the '68 edition
Look at other posts regarding this subject.