Welding 12" sch 40 pipe with 12" sch 20 WN flange 1

[ajnabi01]

Hi Everyone..!

Due to mistake of procurement we have 12" 300# Sch20 flanges delivered at site instead of required 12" 300# Sch40 flanges.

Is it permissible to trim the pipe ends for weldability..?

Line conditions are
Oper. Press.: 24.53 Kg/cm2 g
Design Press.: 48 Kg/cm2 g
Oper. Temp.: 45 C
Design Temp.: 87 C

 

[metengr]

You need to evaluate code of construction design minimum wall thickness.

Considering what happened, I would reject the fitting for use in this pipe system.

 

[ajnabi01]

Design Code is ASME B31.3 and calculated minimum wall thickness on above pressure is 8.45mm which corresponds to Sch40.

 

[ajnabi01]

I understand Sch40 pipe bore can be trimmed to suit Sch20 flange.
My concern is these flanges are to be installed at pump discharge. Should I take the risk of installing Sch20 flanges or not..??

 

[metengr]

NO.