Hello Stressers,

I have come across this one requirement from a client.

"Integrally reinforced branch welding fittings that abut the outside surface of the run wall, in sizes NPS 4 (100 mm) and larger, are not permitted under any of the following conditions:

a)The d/D ratio (branch NPS/run NPS) exceeds 0.8
b)The run piping wall thickness is less than standard schedule
c)The run piping wall thickness is less than 0.75 in. (19 mm) where outside diameter exceeds 36 in. (900 mm)"

What's the possible reason behind this requirement? Is this due to high "stress intensification factor or stress concentration factor" at the branch/header junction? or is this due to fabrication reasons where it's hard to fabricate this type of fitting at the given size and thickness range? When we say "integrally reinforced branch welding fittings", I'm thinking "weldolet" is one of them?

Your opinion is greatly appreciated.

Cheers!!!