Split Flanges

Hi,

I’m working on a project on which we need to replace some badly corroded backing flanges for WN stub ends on a 10”NB CuNi line 150lb system. We have been looking at the options available with regards to Split Backing Flanges.

Personally these are not something I have used in the past so was interested to see what was available.

There are a number of sources I found for split backing flanges manufactured from plate material;
www.precisionflange.com/html/plateProducts.html
www.marzolf.com/index.html

Now these state they supply ANSI class 150 bolt hole patterns but I am concerned as to how the pressure rating of these products is verified & if they are suitable under ASME B31.3

The company I am working for has used split flanges in the past which have basically been two off standard backing flanges split in half, these flanges are then installed back to back with the split lines at 90 deg to each other.

Another option was proposed by a local supplier which was to take two of standard backing flanges and machine them down to fit together much like the precision flange type.

If anyone has any advice on the use of split flanges or point me in the right direction of some good guidance then it would be greatly appreciated.