UG-16 (C) CAPS - ASME VIII Div.1

[ElCidCampeador]

Hi,

does UG-16(c) mill undertolerance apply also to fittings and caps? I've founded in some drawings caps with 12,5% indication but also some other calculation report where this undertolerance is set to zero. Could anyone help me? Thank you!

 

[Afox88]

In accordance with ASME B16.9 2012 Table I-12 Note 2: "A minimum wall thickness of 87.5% applies unless the purchaser specifies a different wall thickness tolerance". Therefore, 12.5% reduction is the usual.

 

[ElCidCampeador]

Thank you!
If I used fittings which are not in accordance with B.16.9 in a vessel designed with ASME, would this tolerance be valid?

 

[Afox88]

If you are ordering a head or other such fitting that is formed from plate, such as an elliptical, f&d head, etc, you do not need to include the 87.5% tolerance. You do need to account for thinning during the forming of the head. Calculations should be done based on the minimum thickness after forming. The vendor of such heads should provide that information.