×
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!
  • Students Click Here

*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.

Students Click Here

Jobs

ASME BPVC Section VIII Div.1 nozzle attachment

ASME BPVC Section VIII Div.1 nozzle attachment

ASME BPVC Section VIII Div.1 nozzle attachment

(OP)
Good morning everyone,

I have two questions. The first is about the ASME BPVC Section VIII Div. 1 code, and the second is about general engineering practice.

First question: In the ASME code a nozzle attached with an internal and external (double-sided) fillet weld, as shown in figure UG-40 (i) has a finished diameter (FD) equal to the inside diameter of the nozzle. This seems a little off to me, I know all full penetration-attached nozzles has a FD equal to the inside of the nozzle, and a single-sided fillet welded nozzle has a FD that is the outside of the nozzle. To me it seems a little odd that a double-sided fillet weld has a FD more like a full penetration weld instead of a single-sided fillet weld. Could anyone offer some explanation to this?



Second question: (This question is more to appease my curious mind) If you need to put a weep hold in a reinforcement plate [to let out moisture and air as the vessel heats up and cools down] why don’t you need a weep hole when you are attaching a nozzle with a double-sided fillet weld? Theoretically there’s a small space for air that gets trapped when you finish welding much like the reinforcement place.

Regards,
Tyler

RE: ASME BPVC Section VIII Div.1 nozzle attachment

TylerM, tough to answer your #1 definitively, but partly, the difference is whether the nozzle is inserted thru the vessel wall or not. See UG-40, sketches (a-1), (j) and (n) for double filleted details where the nozzle ID is not FD.

Your #2, yeah it probably should but in my experience is rarely done. I have seen (not often) a drill & tap thru the hub of a slip-on flange. More rarely, the outside fillet is incomplete. The problem with this is you get rust runs from the lapped surfaces. Looks like crap on a new vessel:) A detail that can be plugged is much preferred.

Regards,

Mike

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

RE: ASME BPVC Section VIII Div.1 nozzle attachment

TylerM

#1 Visualize the assembly from the fit-up stage. You will find the FD is indeed equal to the nozzle ID.

#2 The theoretical air trapped inside is negligible to provide for a weep hole.

RE: ASME BPVC Section VIII Div.1 nozzle attachment

Quote (Dhurjati Sen)

#2 The theoretical air trapped inside is negligible to provide for a weep hole.

Unless you are hydrogen service, in which case you shouldn't be using a double fillet anyway :)

Regards,

Mike

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

RE: ASME BPVC Section VIII Div.1 nozzle attachment

(OP)
Thank you everyone for all of your help and insight. I'm glad to know that someone (although rare) has addressed the air on the inside of the fillet welds.

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