Which gasket material is not acceptable for use in gas piping flanges?

Rubber is not an acceptable gasket material for use in gas piping flanges primarily due to its tendency to deteriorate when exposed to hydrocarbons and other elements commonly found in gas. This deterioration can lead to leaks, which pose serious safety risks in gas systems.

In contrast, fiberglass, neoprene, and silicone gaskets have properties that make them more suitable for gas applications. These materials are generally more resistant to chemical breakdown and can withstand the pressures and temperatures associated with gas piping systems. Fiberglass offers good strength and rigidity, neoprene provides excellent resistance to oils and chemicals, and silicone gaskets are known for their flexibility and high-temperature resilience. Therefore, using rubber as a gasket in gas piping flanges can compromise the integrity of the system and violate safety codes.