PetroStreet

Today I saw few triangular flanges installed on 4" natural gas line. Is this an obsolete type or special type of flange? for any specific function?? One of the flange was leaking. How to design a leak sealing clamp for such type of flange?
Regards

Against which piping code the piping has been designed?
I have seen triangular flanges in low pressure services but very rare. At my present site, I think there isn't a single one.
You can do leak sealing of such flanges by making a box-up clamp for the whole flange body. The only thing to be considered is that you may or may not recover the flanges depending upon the nature of service.
Box-up in two halves can be made by providing gasket sealing on both sides of the flanges.

Hope this would help.

Arcpro,

Piping was designed on ASME B13.3, however, this belongs to a relocated plant from USA.
Line operating pressure is around 150 psi and service is natural gas, which restricts any hot work on the leaking flange / pipe.

Thank you for your suggested solution of bolted box-up for whole flange. We are working on the same lines. Will share the outcome of leak sealing efforts once completed.

Meanwhile, a relevant article comes to my reading, describing the similar repair method. Attached is sharing for common knowledge.

Regards

Good document.
Do you have any design calculations for that?