Limit compressed, non-asbestos fiber gaskets to temperatures <250F (they have lots of rubber in them). Use a reinforced graphite gasket between 250-600F. Above 600F graphite will oxidize with time and create leaks. Foil or tang reinforced graphite sheet gaskets are much better than pure...
You are going to end up with many leaking RTJ gaskets if they're installed with low skilled labor. You had better have assembly training for these fitters and a defined assembly procedure and target torque value if you stay with RJ flanges. You didn't mention temperature or pressure, but I...
Another proven approach is to fit an adapter ring outside the RF of the mating flange, which essentially converts the RF flange to a FF flange. Then use an full face or Reduced Area (OPRA) gasket. Both flanges must be the same NPS and pressure class.
You need to look at the total bolt load required to seat the SW gasket, and then convert that load into assembly bolt torque. Good luck trying to seat a hard, inner ring SW gasket with low stress B8M bolts. If you must use stainless bolting, you'll likely need to upgrade to B8M Class 2 (strain...
Spiral wound gaskets may not be the panacea that you think. You have to fully seat them first, and many class 150 flanges do not have adequate bolt load to seat down to the guide rings.
There are several WRC Bulletins and PVRC projects that have looked at the effect of external bending moments...
Throw out your used bolts, install new B8 bolts (preferably strain hardened class 2- and make sure that your supplier really does supply class 2), calculate the assembly torque required staying below 60% of yield if possible, then use controlled torquing following the legacy (star pattern)...
Coated (Xylan) bolting will provide improved atmospheric corrosion resistance and consistent effective thread lubricant for assembly, however this coating should not be relied upon to provide chemical resistance. It won't.
B8 or B8M class 1 bolts/studs should be avoided if at all possible. They are low strength and their use in piping connections will seriously limit your available gasket choices. They simply cannot develop the compressive load needed to seat many gasket materials; especially in class 150...
Flexitallic and all SW gasket manufacturers produce inner ring (CGI style) spiral wound gaskets in both 316 and 304 metallurgy. Fact.
Confirm that your service is chemically compatible with either 304 or 316 an then standardize on one if compatibility allows.
Do you need both PTFE and Flexible...
Conventional torque wrenches are limited to 250 ft-lb. Some larger torque wrenches will take you up to 600 ft-lb. In addition to the inaccuracies of torque, it's gets to be a safety risk pulling on wrenches to develop 600 ft-lb. I suggest using hydraulic torquing or tensioning at torques >250...
Agree with Stanier. Unreinforced elastomer gaskets should be used at pressures <100 psig. Fiber reinforced non-asbestos gaskets are a good choice as long as you have adequate bolting. B7 for instance. With flat face cast iron flanges you'll need full face gaskets and that's a lot of area to...
