Metallic gaskets are used for pressure and temperature extremes that cannot be handled by nonmetallic gaskets. If the product of operating pressure in psi times operating temperature in °F exceeds 250,000, metallic gaskets should be used. Metallic gaskets are also used for temperatures below -65°F, above 850°F, and for pressures above 1,200 psi. Other conditions calling for metallic gaskets include vacuum below 10-4 torr and radiation above 108 rad.