I want to know which one is correct

[yongheekim]

I want to know which one is correct among the following three when flange pressure rating is indicated:

ASME/ANSI 16.5 CLASS 300 RFWN
ASME 16.5 CLASS 300 RFWN
ANSI 16.5 CLASS 300 RFWN

Thanks

YONG H. KIM

 

[KANN]

I would say - none of the above!

I would use ANSI/ASME B16.5 Class 300 RFWN.

See

http://www.nssn.org/search.html.

 

[PAN]

Don't forget to mention about material, size and thickness of flange neck.

 

[yongheekim]

what do you mean by your comment?

 

[metaltrade]

the second one. the ansi was drop in the 90's.

 

[DSB123]

The correct designation is:-

ASME B16.5 Class 300 Lb RFWN

As stated there are many who still use ANSI B16.5 as the designation mistakenly. ANSI B16.5 Standard does not exist anymore.

 

[mtk220]

Hi Yong,

Actually the correct designation would be
ASME B16.5 Class 300 RFWN. There is no lb (pound) in the correct designation. However it is also important to list the bore diameter to ensure that it matches the pipe.
In my company we do the following:
There is a note on each piping drawing that states "ALL FLANGES ARE IN ACCORDANCE WITH ASME B16.5 UNLESS OTHERWISE NOTED." The BOM description would then be:
"FLG 6.00/300 WN SCH 40" which means it is a 6" Class 300 raised face weld neck flange with a schedule 40 bore.
Here's the history...
It was ANSI, then it went to ANSI/ASME, and now it is termed and ASME specification. But no matter which way you term it almost everyone will understand. Many people still refer to flanges as ASA. ASME is now correct but it will be sometime before it is fully adapted. It takes forever to catch up. Because of the costs, many small companies don't maintain the standards as well as they should and work with older versions much longer than adviseable.
For the record,
ASA = American Standards Association (+ a half dozen other associations)
ANSI = American National Standards Institute
ASME = American Society of Mecanical Engineers

 

[KANN]

I agree the B16.5 is now strictly an ASME standard. I checked through the ANSI website and thought B16.5 is still a ANSI approved standard. My appologies as it clearly is no longer approved by ANSI.

Unfortunately,the improper designation is still being indicated by some suppliers (eg.

http://www.buffaloflange.com).

Also listed on NSSN (National Standards Systems Network, an ANSI website product) is: BSR/ASME B16.5-199x and BSR/ASME B16.5, Part II. I understand the BSR prefix to indicate Board of Standards Review (ANSI). It is not clear to me whether B16.5 is under review again by ANSI or whether this designation is used to indicate withdrawn standards. The latest ANSI newsletter on standards actions does not indicate any activity on B16.5. Can anyone clarify?

 

[DavidCR]

I would add:

Sizes: Use ASME B36.10 to specify the correct size or NPS nominal pipe size).

Use for example -NPS 6-. And avoid to use: -6"-, -Nominal diameter: 6"-, or other designation that would be understood, but is more correct to call for -NPS 6-) and can help you if you are dealing in an international environment.

And about PAN´s:
The material: for carbon steel pipes the most common is ASTM A105, you have to specify the correct material for the correct materials group included in the B16.5 standard.

I agree with: ASME B16.5, Class 300, WN. RF.

ps.
Take care since B16.5 is limited to sizes to 24 NPS, if you are thinking of big flanges the thing gets more complicated.