Small bore flanges

[isg1968]

Flanges
When piping engineer is developping material class specification for a service e.g Class 600 pound, size flanges less than 2 inch should be 2 rates higher than 600 pound which will be 900 and 1500 pond (same approch for valves). Can someone tell me which codes(ASMEB...) is this statment from ?

 

[BigInch]

Its NOT code. Maybe its a company specification, probably originating from some old guys experience, to provide for extra mechanical strength.

BigInch-born in the trenches.

http://virtualpipeline.spaces.msn.com

 

[LSThill]

What is the services?
Piping Classfiication Speiification 1) limited by B16.5; and or 2)Calculation.

 

[moltenmetal]

Not only is this practice not founded in "code", it would seem to be based on confusion about how flanged piping actually works.