RTJ Gasket torque specs

[garnet1]

I am having a hard time finding a generic torque table for type R ring joint gaskets when used in B31.3 piping. Has anyone got any info? Can I use API 6A tables?

 

[aybee]

thats a good question, I would like to know the answer to that also..work out the bolt loading from ASMEV111 div 1 flange design rules it has values of M &y for ring joints then you can get a torque from the bolt loading value

 

[tothepoint]

I would recommend you not develop assembly torque values based upon sect. 8, div.1, app. 2 design rules. You will end up with bolt loads that are WAY too low. Appendix 2 is for design, not assembly. You can contact the ring joint manufacturer, but I'll bet they won't be much help. I typically use a seating stress of 40,000 psi and calculate the contact area of the gasket which are the tapered edges of the gasket (not the top and bottom). You should be using high temp/high strength fasteners, and you'll need at least 50% of its yield strength.

 

[aybee]

agree TOTHEPOINT,the design bolt stress often ends up not enough, I usually work to min 45000psi bolt stress with an upper limit of 60% of bolt yield under normal circumstances with 80% being the top limit.This is on ring joint and CMG type gaskets.

 

[deanc]

Have alook at SecVIII Div I Appendix S. The Industrial Fastners Institute also has a good handbook called Fastner Standards.