Phenolic resin gaskets

[Gorpomon]

Hi,

I have a cotton and phenolic resin gasket with Neoprene adhered to both sides, its full faced. It looks like a brown hunk of resin with a thin sheet of black Neoprene on each side, you can tell its two distinct materials.

I am trying to calculate appropriate bolt loads using ASME Boiler and Pressure Vessel Code, Section 8, Div. 1.

I can not find an appropriate m & y value. Is it just the listing for an elastomer with cotton fabric insertion, or the listing for an elastomer with hardness > Shore 75A? (My gasket is RockwellM 100, which I found equaled Shore 85D, which I found was well above Shore 75A.)

Should I not be using this and instead peruse the PVRC/Tightness method, if I so I run into the same problem of not knowing what materials Gb & Gs value to use.

Any help would be VERY appreciated. Also, any tips in general on how to apply BPVC Section 8 to unknown gasket materials would be so great.

Thanks, long time reader, first time poster!
-Ron

 

[gr2vessels]

Gorpomon,
1. You don't apply BPVC to unknown gaskets and viceversa, do not use unknown gaskets in pressure vessel design.
2. You must be very sure of the gasket material to attempt matching it with the listed m and Y properties in Table 2-5.1 of Appendix 2.
3. If the gasket material was manufactured by a gasket manufacturer, he should be able to give you the m,Y values tested and guaranteed. Otherwise, how would you ensure a leak free joint? Assuming or hoping?
4. However, if you can ensure the quality of your gasket material is matched with the elastomer with cotton fabric insertion, then use 1.25/400 psi values. The elastomer gasket is a rubber gasket for light duty.
By the way, what are you trying to seal?
Cheers,
gr2vessels

 

[Gorpomon]

Thanks for your reply. I should have specified some details. This is not for any application right now. We are just trying to develop a general guide for what value to torque nuts to depending on pipe diameter and service pressure.

We have a spec sheet from the manufacturer, and it lists mechanical properties such as tensile, compression and flexural hardness. As well as hardness, impact strength, etc. However it does not list m & y values. I have yet to get a reply from the manufacturer on this issue as well, so I'm looking at other methods finding my answer. Is there any way to relate mechanical properties to the m & y values?

I'm new to gaskets, so if possible can you give me an idea of what my options are for this situation?

 

[gr2vessels]

It's really not that complicated as you are trying to reinvent the wheel;- you should look for a reputable supplier of gaskets in your area, ask for a product catalogue and select from there the gaskets suited for your application(s). Then send an email to the manufacturer and ask him to provide guaranteed values of m/Y for those gaskets. If he replies with the description of the Table 2-5.1 of Appendix 2 in ASME VIII, then tell him off and look for another manufacturer. Eventually you'll get to the manufacturer (like I did), who will give you tested and guaranteed m/Y values and you stick with him. Those values will probably be less than the old cookbook got in the mentioned table, but you shouldn't trust that table anyway. Just read the Note 1 below that table...Also, try ASME P6C-1-2000 standard for your torque requirements.
Cheers,
gr2vessels