available length of reinforcement

[stephenebrady]

Branch connections to ASME B31.3
In section 304.3.3 the length of branch available for reinforcement (L4) is determined from two formulae and the lesser of the two is used.
In my problem, this value is 1000mm.
However, if there is a flanged connection only 500mm along the length of the branch, is it necessary to limit L4 to 500mm, or is this being very conservative?
Also, does it make a difference if the flange is a connection to an isolation valve?

 

[prex]

Though this doesn't seem to be explicitly said in B31.3, it is obvious that the available area must be really available, and you can't count on metal in the flange, as this is required by the flange itself to resist.
However your figure of L₄=1000 mm is really surprising: what kind of a huge thing are you speaking about? prex

http://www.xcalcs.com

Online tools for structural design

 

[stephenebrady]

Sorry, my mistake.
L4 is actually very short.
d2 is the length I was using which is NOT along the length
of the branch but along the length of the pipe itself.
Hence the flange on the branch is irrelelvant.

Thanks Prex, as I thought, you can't take the compensation from the flange.

Cheers..problem solved