I noticed that the new 2004 edition of ASME B31.3 now references ASME
B16.48 1997 for blinds, however, the blind thickness calculation in section
304.5.3 of B31.3 is still the same.  In some cases, the B31.3 calculation
requires a thicker blind than specified in B16.48.  Now that it's listed
as a reference standard in B31.3, what does this mean?  Does it mean the
B31.3 recognizes B16.48 thickness as being acceptable to the flange rating
of the same material with the same corrosion allowance?

Regards

Hi Anindya,

I think the committee will catch up with that and maybe you can help. The only thing you will get at this forum will be individual opinions. There needs to be an inquiry sent to the Code Committee to have an interpretation of the Code rules. The next meeting of B31.3 is close at hand so an inquiry will go through the Committee very quickly if you send it.

Regards, John.

John,

Thanks for your response.

I have never sent any query to B31 commitees. Kindly let me know if queries can be sent by e-mail.Along with the aforementioned question, I have two more queries.

Best regards

Anindya

Hi Anindya,

I see your point. I am thinking that the process shown in B31.3 Appendix Z (mail) might be too time consuming. Perhaps Dave Diehl will be willing to "carry the ball" for you as he will be at the next meeting. If you ask Dave via email perhaps he will frame the question in "Code speak" and submit your questions as "his" questions. There are many precedents for this. I would do it for you but it looks like I will be in Ft. McMurray, Alberta, and will only be able to nip in at the end of the week for the Mechanical Design Committee meeting.

"Code speak", would have you frame your questions such that they could be answered as "yes" or "no". John Luf provided examples on this forum as to how the Committee would "rephrase" incoming questions in his responses to the "Occasional Stress" thread, below.

The most useful questions for the Code Committees are those that come from actual piping engineers that are using the Codes. I would encourage ALL Code using piping engineers to participate by sending intelligent inquiries to the B31 Committees. This will make for more useful Code documents.

John Luf presented this information in another thread:

Link for preparation of inquiry per B31.3 http://cstools.asme.org/csconnect/pdf/CommitteeFiles/3565.PDF

Contact information for B31.1
James N. Shih
The American Society of Mechanical Engineers
Three Park Avenue
New York, NY 10016
Phone: (212) 591-8539
Fax: (212) 591-8501
shihj@asme.org

Contact information for B31.3
Noel Lobo
The American Society of Mechanical Engineers
Three Park Avenue
New York, NY 10016
Phone: (212) 591-8540
Fax: (212) 591-8501
lobon@asme.org

Regards, John.

One mans opinion....

Once a standard is listed it is part and parcel to the code. My guess would be that blinds that meet that standard in its entirety would be acceptable....

Not having B16.48 in front of me my guess is that it may cover more than just thickness per se.

Send an RFI in... our next meeting is next spring but we may get back to you before that... prepare the RFI yourself this will help you to think of it from the codes perspective....

The B31.3 Section recently approved a change to paragraph 304.5.3 (Blanks) that will point to ASME B16.48. Paragraph 303 points to Table 326.1 (Component Standards) and Table 326.1 lists B16.48.

The new Code should read:

"304.5.3 Blanks
(a) Blanks not in accordance with para. 303 or 304.5.3(b) shall be qualified as required by para. 304.7.2

(b)"[existing text]

Two more reviews must be completed before this change is approved for inclusion in B31.3 - 2006 Edition.

Huh????

The question concerns now.... the current 2004 edition.... as to 2006 I would place no bets on when or how.... but hopefully it will appear in 2006 calendar year

...............and one would certainly hope that if it will not be fixed before the 2006 edition is issued, a interpretation would be forthcoming in the much more immediate future(?).

Steady as the Rock of Gibraltar........

John C Luf/Dave/John Breen,

Thanks a lot to all of you.I will send my questions to Dave via e-mail and Dave in turn can place it to the code committee in CODE SPEAK.

Best regards

I'm going to try avoiding a little more work by doing a little more reading...

"302.2.1 Listed Components Having Established Ratings. Except as limited elsewhere in the Code, pressure-temperature ratings contained in the standards for piping components listed in Table 326.1 are acceptable for design pressures and temperatures in accordance with this Code."

If B16.48 does not provide specific ratings, then 302.2.2 may apply.

"303 General (Pressure Design of Piping Components) Components manufactured in accordance with standards listed in Table 326.1 shall be considered suitable for use at pressure-temperature ratings in accordance with para. 302.2.1 or para. 302.2.2, as applicable. The rules in para. 304 are intended for pressure design of components not covered in Table 326.1..."

From these two excerpts, I do not believe it is necessary to forego ASME B16.48 (listed in Table 326.1) and instead use para. 304.5.3 rules for blanks.

Blanks per ASME B16.48 are listed components and therefore acceptable. See para 303. The pressure-temperature rating of these are based on pressure class and are per B16.5.

Alternatively, blanks may be designed per the equation in 304.5.3(b.