A compressible gasket composition appears to exhibit a critical strain for a compressive strength failure. The strain is defined from plots of stress or strain versus weight density of the gasket in the state of compression. A method is suggested for measuring the critical strain in joint assemblies exposed to a service environment. Also mentioned is the relationship of the strain to the stress, time, temperature conditions required for a strength failure. A flange test is pointed out as an approach to evaluating strength for elastomeric gaskets. Practical design guides are listed for increasing the resistance of nonmetallic gaskets to strength failures in flanged joint assemblies.