SORF Flanges

Found on the internet after a brief search:

http://wiki.answers.com/Q/What_is_SORF_flange

For the first two letters: SO = slip-on, SW = socket weld, WN = weld neck;
For the next two lettere: RF = raised face, FF = flat face.

These are the most common, but there are also female threaded flanges whose designation I forget, and also Van Stone flanges (movable flanges backing up a 90° flared pipe end).

Go here and read all about Flange types.

http://www.pipingdesigners.com/Training%20-%20section%201d.htm

To answer your first question, you need to know the answer to ur second question: 1- what are the types of flanges.

refer any piping handbook and also refer ASME B 16.5 to understand the flange constructions, types of flanges.

2-What are SORF flanges?

SORF-slip on raised face

Unlike WNRF flanges, these flange just slip-on to the O.D of the pipe and are fillet welded with them, instead of butt welding. (WNRF flanges are butt welded with the pipe).This fillet welding makes them to use in low pressure/ less severe lines like instrument air, cooling water, raw water etc.

Another case where SORF flanges are mostly used are in case of piping material being SS or Non ferrous -NF (exotic).In these cases we can go for CS(carbon steel) SORF flanges over SS/NF pipes to save on piping item cost.

Other members kindly correct my statement if i am wrong somewhere.

SLIP ON RAISED FACE FLANGE

this type of flanges use up to rating 300# only , in larger rating it is to favor to use WNRF welding neck raised face flange up to 600# rating , then from rating 900# use WNRJT welding neck ring joint type flange.

in special cases in pressure vessel and piping it could be used ( self reinforcement flanges)