Pipe support attachments to Chapter IX pipe 1

[PipingGB]

Are full encirclement pads required for pipe support attachments to Chapter IX piping similar to that required for Pipeline codes. The code does not acually say they are required but it is a point of debate in the office.

 

[C2it]

The primary intent of the circumferential welds only rule is, I believe to avoid other stresses aligning with the hoop stress direction, generally in relatively thin wall, high yield applications such as B31.4.

Vis-a-vis Chapter IX pipe .... high pressure, very heavy wall, common sense says don't screw around with local stresses. It will be a boom, rather than a bang. However, thinking of Lame pressrue equation, that accepts that in heavy wall there is a reduction of hoop stress across the wall and less at the outside (assumed constant in many codes). Does that suggest a longitudunal weld may be ok ?

For comfort, I would still use circ. only.