Flange Elastomer fabric Gasket Sealing Toque

[NewENG102]

Hi, I need some help calculating torque required to seal elastomer fabric flange. I am new to this and need some help.

Pipe ID = 12"
Pipe OD =19"
Pipe BC=17"
Bolt Hole = 1" dia 12 holes
Bolt Dia =0.875"
Retaining Ring ID = 10"
Sealing Area = 518.25 in2 (Pipe OD Area - Ring ID Area)(excludes bolt holes for simplicity)
Pressure = 100 psig
Gasket Factor "m" = 1.25
Seating Stress "y" = 400 psi
Joint contact width "2b" = (19"-10")/2 = 4.5"


I need to figure out the torque required at operation of 100 psig

Any help would be greatly appreciated.

 

[TGS4]

1) What does the gasket manufacturer recommend?
2) What lubricant are you using on the bolts and nut-to-flange face?
3) What assembly technique (e.g. star-pattern, 50-70-90-100 with 2 circular passes @ 100%)?
4) What training have the assembled received you ensure that they will assemble it correctly?
5) When was the last time the torque wrenches were calibrated?

 

[NewENG102]

1) What does the gasket manufacturer recommend? I am trying to use the ASME Boiler code to determine the torque- This way I can always calculated it on my own.

2) What lubricant are you using on the bolts and nut-to-flange face? K = 0.2

3) What assembly technique (e.g. star-pattern, 50-70-90-100 with 2 circular passes @ 100%)? Star Pattern

4) What training have the assembled received you ensure that they will assemble it correctly? I am trying to understand how to apply the ASME Boiler code to determine torque

5) When was the last time the torque wrenches were calibrated? I am trying to understand how to apply the ASME Boiler code to determine torque


I want to use the ASME Boiler code (Wm1, Wm2) to calculate the torque with the given values above.

 

[TGS4]

Under no circumstances should you use Appendix 2 of VIII-1 for actual installation purposes. See the cautions in Appendix S.

If your are interested in learning this stuff, refer to ASME PCC-1.

 

[gasketguru]

This sounds like a regular 12"-150 flange, presumably flat faced (not with a 15" raised face), so you have full contact. Note that rubber does not compress it only displaces, so if you over-load it then it squeezes out of the side of the flange. I don't get your area calculation - 12" x 19", or even 10" x 19" is a lot less than 518 in^2, and the 10" "retaining ring" is not clear either, if it is smaller than the pipe bore.

A regular 12"-150 gasket as full face would normally be 12.3/4" I/D x 19" O/D with holes as you describe, so a contact area of 146.4 in^2. As has been mentioned already the traditional ASME code calc may not give the best results - perhaps start with around 800-1000 psi as a gasket stress on this joint (we don't know what hardness and modulus your rubber insertion gasket is here), but this then gives us about 10,000-12,000 lbs/bolt. Friction on the threads and under the nut can vary considerably (are washers used, did you lubricate threads and nut face etc.) - with a basic "nut factor" of 0.2 you could estimate 11,000 x 0.2 x 0.875/12 to get 160 ft-lbs, which might be a reasonable starting point. The stress at the root of the bolt becomes about 25,700 psi, so I assume the bolt grade is sufficiently strong. If the gasket is extruding too much then stop at a lower value of course.

 

[Duwe6]

ASME PCC-1, like TGS4 recommended. And don't overthink it. Evenness of 'squeeze' [bolt torque] and proper alignment of the flange halves is much more important than an exact value. Willing to bet a paycheck that 75 ft-lbs will seal it properly IF the flange is assembled correctly and torqued up in stages and in a proper pattern. Technique is MUCH more important than the torque value.

 

[rconner]

While I am likwise thrown off a little by the OP stipulation, "Retaining Ring ID = 10", for what may be an essentially 12" flange joint, I would add that it is also advisable to select/apply non-galling bolting material and with clean threads, and also make sure flanges are not bolted up in any bind ;>).
About only other comment I'd make with regard to "elastomer fabric" gasket is that if service is no more than 100 psi I'm not really sure fabric reinforcment is really necessary or desirable for such service [while I guess it's possible designers of modern gaskets have over the years solved the problem by design or manufacture, I think I have seen some instance many years ago where a sort of weeping or wicking (within the gaskets) alongside the embedded fibers occurred, even with some pretty hefty bolting.]