SA 234 WPB Pipe caps 1

[djmret]

What is the MAWP of SA 234 WPB welded pipe caps and where can the information be found?

 

[kwaliteitshenk]

djmret,

As far as I know there is no MAWP related to the pipeschedule of a pipecap in the ASME Code. Just make a calculation for an ellipsoidal head.

Good luck

 

[JStephen]

I don't know that I've seen anything that actually says what the shape of a pipe cap is.

 

[SnTMan]

Don't the fitting standards specify the ratings? I was thinking fittings were rated for the MAWP of the pipe of like schedule.

Regards,

Mike

 

[metengr]

The information can be found in ASME B16.11 for forged fittings, socket-welded and threaded.

 

[PEHasan]

Pipe cap is actually a 2:1 semi-ellipsoidal dished head. Therefore, refer to UG-32 to calculate the MAWP of pipe cap.

 

[NozzleTwister]

SA-234 is covered in ASME B16.9 Factory-Made Wrought Buttwelding Fittings.

NozzleTwister
Houston, Texas

 

[johnnymist2003]

Hi all,

PEHasan, I'd suggest that you approach your weld cap supplier for some dimensions of the weld caps.UG-32 design for 2:1 semi-ellipsoidal heads require the head shape to be truly ellipsoidal, or if manufactured using two radii then the crown radius must be 0.9D and knuckle 0.17D.Most weld cap suppliers I've encountered manufacture their caps using two radii, that are not necessarily within the 0.9D, 0.17D limits.This would mean that the UG-32 design for 2:1 S/E heads will not be valid for the weld cap.It would need to be designed to Appendix 1.
John

 

[mrsteam]

ASME B16.9 table I-10 (Dimensions of Caps), General Note (2) indicates that "The shape of these caps shall be ellipsoidal and shall conform to the shape requirements as given in the ASME Boiler and Pressure Vessel Code."

Given that, if a manufacturer tells me that their cap conforms to ASME B16.9, then I can assume that the shape is ellipsoidal, and thus these formulas should apply.

Any thoughts?

 

[ijzer]

If used for piping (B31.3) the cap does not need to be calculated. It shall be the same thickness as the calculated pipe wall. So the maximum allowable pressure is depending on the temperature and the selected schedule size.