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Bolt tightening torque for EPDM gaskets

Bolt tightening torque for EPDM gaskets

Bolt tightening torque for EPDM gaskets

We have to use raised face steel flanges mating flat face flanged cast iron valves.

I know that it is not recommended to use iron flat face flanges with raised face steel flanges, but we donĀ“t have time to buy new flanges.

We are using:
-Rubber gaskets, EPDM, 1/8" thickness, brand: S.H. but I cannot find information from the vendor of the gasket.

-Class 150 ANSI B16.5 1/16" slip-on, raised face flanges, A105, carbon steel. Diameters: 4", 6", 8" and 10".

-Water, design pressure: 150psi
I want to know if somebody could comment on the case and if someone know what would be a recommended tightening torque for the bolts that could be safe for the cast iron valve flanges.

RE: Bolt tightening torque for EPDM gaskets

Could you just have somebody in your machine shop (or whoever you use) take the raised face off the flanges, or are these already welded in place? In any event, it's unlikely that an experienced fitter, using an ordinary 1/2" drive ratchet would or could normally tighten the flange bolts to the point of damaging something. If there's a guy on the fitters crew nicknamed "Hoss" or "Bull", don't let him tighten the bolts. :)

RE: Bolt tightening torque for EPDM gaskets

I assume that the steel flanges you mentioned are ANSI`s.
Dig into web pages or garlock, flexitallic or may be kemptchen of Germany (they have ANSI gaskets). You`ll probably find there practical torque tables instead of doing calculations.

RE: Bolt tightening torque for EPDM gaskets

I ran into this problem some years ago ...cast iron valve mated up to raise face steel flanges. AND as aways there wasn't enough time to correct the surfaces. SO what we did was make some adapters from 1/16" bass shim plate. They fit around the raise face section with the proper bolts holes cut into these adapters. SO what you were doing was making the raised face section into a flat face configuration. They have been in service about 8 years now with no problems. Good Luck!  ...Mark

RE: Bolt tightening torque for EPDM gaskets

The recommendation from 11echo is right-on.  You need to use these adaptors to turn your RF flanges into FF flanges or else you're very likely to:
1)  Crack you CI flanges or
2)  Over-compress the EPDM gasket because of the small contact area of the RF flange.  

You can use any hard, chemically/thermally compatible gasket material for these adaptors.  Use a full face EPDM gasket instead of a ring gasket.

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