why skirt longitudinal seam and circumferential seam efficiency is taken as 0.7 and 0.49 respectively??.. please help me to know basis behind this.. thank you .

The 0.7 Efficiency on long. seam is arbitrary, because this applies to Type 1 weld (pressure retaining) without RT. I don't think it can be applied to skirt with loads other than circumferential of pressure vessels.
The 0.49 I presume to be the factor given to S (in tension) to the calculation involving shear. Presuming the circ. seam it applies is only the attachment skirt to bottom head
mauro

Dear Members,

Could i know where you refer joint efficeincy, E=0.49 for circumference seam?. It is lapped joint skirt to head?

Thank you.

_________________
Faizol
(PV-elite User)

ya, it is lapped joint skirt to head.

thanks .

I believe it is because it is subject to shear not tension
Mauro

See ASME VIII div. 1 UW-15 and Pressure Vessel Design Handbook, by Bednar

regars

rhg