INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Jobs

U- Stamped Equipment - Machining of WNRF Flange to WNFF Flange

U- Stamped Equipment - Machining of WNRF Flange to WNFF Flange

(OP)
Hi,

One of our projects, the contractor machined the WNRF Flange of U-Stamped Static Mixer to Flat face to match with the connecting piping. The equipment is new and the design code is ASME Sec-VIII Div. 1. Is it acceptable to convert the flange face of U- stamped equipment without following R-stamp procedure? Your expert reply/ suggestions are highly appreciated.

Thanks in advance,

Regards,
Sajeev

RE: U- Stamped Equipment - Machining of WNRF Flange to WNFF Flange

Sajeev P, assuming a B16.5 flange, that standard permits conversion from RF ot FF by machining off the raised face as long as tabulated thickness dimension "tf" is maintained. See 6.3.2.

Again, assuming B16.5, if this were done before hydro I'd see no need for an R stamp, afterwards I'd still say not, but it'd likely be up to the AI.

Regards,

Mike

The problem with sloppy work is that the supply FAR EXCEEDS the demand

RE: U- Stamped Equipment - Machining of WNRF Flange to WNFF Flange

Even after hydro I can't see an issue with this. The RF bit is not part of the structural strength of the flange as SnTman explains, but agree that the decision isn't ours to make, but the AI. I would hope sense would prevail here.

You haven't changed or repaired anything and it remains a compliant ASME B 16.5 flange so long as he doesn't remove too much of the flange material....

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

RE: U- Stamped Equipment - Machining of WNRF Flange to WNFF Flange

Have machined a ton of flanges on U-stamped equipment without ever even thinking about an R-stamp. Always assumed if you're still within B16.5, you're good to go.

NB Interpretation 98-30 seems to back me up on this

Addresses damage during operation, but I've machined damaged flanges all the way down to FF (as allowed by B16.5). I don't see how converting it wouldn't fall under the same interpretation:

Quote (National Board)

Question 1: A pressure-retaining item has its surface ground or machined to remove imperfections caused during operation. Is the resulting reduction in outside diameter, length, and thickness caused by such grinding or machining considered an alteration as described in Appendix 6, Item C4?

Reply 1: No, unless the changes affect the pressure-containing capability of the pressure-retaining item.

Question 2: A pressure-retaining item has its surface ground or machined to remove imperfections caused during operation. The grinding and machining reduces the item’s thickness, length and outside diameter. Must such grinding or machining be performed by a holder of an "R" Certificate of Authorization?

Reply 2: No.

Nathan Brink

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Resources


Close Box

Join Eng-Tips® Today!

Join your peers on the Internet's largest technical engineering professional community.
It's easy to join and it's free.

Here's Why Members Love Eng-Tips Forums:

Register now while it's still free!

Already a member? Close this window and log in.

Join Us             Close