An automated apparatus and test procedure was developed to test elastomers for explosive decompression (ED) resistance.The apparatus utilizes a cyclic gas
pressurization followed by rapid decompression.The test continues until the one of two elastomeric O-rings in the apparatus fails and pressure is
transmitted,automatically shutting down the test. A study was done to determine optimum gas soak period and to screen some common O-ring materials. Preliminary results show different gas permeation rates for different materials. The validity of the test technique to screen elastomers for ED resistance is shown.