Although perfluoroelastomers were designed for high temperature and severe service, they have become the preferred elastomeric material for high pressure oxygen applications. The main reason for their widespread use in oxygen is that perfluoroelastomers typically perform better in most ASTM standard test methods designed for evaluating oxygen compatibility. The principal disadvantage of the use of perfluoroelastomers is that they are prohibitively expensive — approximately 50 times the cost of most other elastomeric materials.
The ASTM standard test methods that are used to evaluate oxygen compatibility of elastomeric materials do not necessarily measure the resistance to ignition in oxygen of o-ring materials in their use configuration. The seal configuration tester (SCT) simulates a typical dynamic o-ring application and is therefore a better method for comparing the relative wearability and oxygen sensitivity of various elastomeric o-ring materials. while data from the ASTM standard test methods suggest that perfluoroelastomers may be less oxygen sensitive than other materials, data from the seal configuration test demonstrate that fluoroelastomers are superior to perfluoroelastomers in a dynamic o-ring use configuration. Seal configuration test data were also compiled for other elastomeric materials such as butadiene nitrile and silicone. This data are compared to the test data for perfluoroelastomers and fluoroelastomers and are discussed in the paper. The seal configuration test data provide additional information to aid in the selection of elastomeric materials for high pressure oxygen o-ring applications.