ASME Flange O.D. Tolerance

[nctexan22]

I cannot find documentation governing flange O.D. tolerance in B16.5. Paragraph 7 (Tolerances) lists those for facings, but not for actual flange O.D. Am I looking in the correct place?

 

[JohnBreen]

nctexan22

Go here:

http://www.maassflange.com/downloads/ANSI_B16.5_Dimnsion_Toleran.pdf

I really like Google.

Regards, John

 

[jte]

On the link which John provided, be sure to read the asterisk note. Also note that although they are in the flange business, they still don't seem to have noticed that its ASME B16.5, not ANSI B16.5. Maybe we need a date tolerance?

The interpretation below is a bit old, but I don't think that anything has changed. I particularly like Reply 2!

jt

Interpretation: 2-10
Subject: Outside Diameter Tolerances
Date Issued: July 3, 1990

Question (1): Does B16.5-1988 have any requirements for tolerances on flange outside diameters?

Reply (1): No.

Question (2): Why not?

Reply (2): The ASME B16 Committee does not respond to questions about rationale for requirements.

 

[JohnBreen]

jte

Thanks for that. I don't think that we have ever used that answer within out B31 Code Committees but I like it and I will "keep it in my hip pocket for "contingencies".

John

 

[nctexan22]

Much appreciated.

 

[unclesyd]

I just talked to to a retired fitter with over 50 experience who stated that the most difference he has seen any in any two flanges is about 1/8" and this is not a very common occurrence.
He also stated that when there were only a few suppliers of flanges in states he stated you could almost straight edge any two flanges and the disparity has come on in last 20 years or so.

Anecdotal:
This gentleman has about every book and pamphlet written on pipe fitting. He also has a complete collection of the catalogues from the major flange supplier like Taylor Forge, Tube Turns, etc.
Many year ago he showed me how to square a square along with a few other tricks with square.