SYMPOSIA PAPER Published: 01 January 1991

Ignition of Nonmetallic Materials by Impact of High Pressure Oxygen III: New Method Development


The gaseous oxygen pneumatic impact test has been used by NASA to evaluate the suitability of nonmetallic materials in high-pressure oxygen systems. Several studies have been conducted in the past few years to evaluate the repeatability and applicability of the test. These studies showed that the test has an unacceptable degree of variability. It was recommended that new methods be developed for evaluating the suitability of materials for use in high-pressure oxygen systems. A modified pneumatic impact test was developed and evaluated which addresses the problems of the test currently used by NASA. The test system modifications included a view-ported specimen chamber to view ignition, larger volume between the impact valve and the specimen, ability to adjust pressurization time, and a modified specimen size. Test procedure modifications included subjecting the specimen to a single impact (the current NASA test method required 5 impacts per specimen). The ignition properties appeared to be controlled by the autogenous ignition temperatures of the specimen materials. The modified test allowed the prediction of ignitions that have occurred in component tests and in field incidents that the method currently used by NASA would not have predicted. It is recommended that pneumatic impact ignition tests be performed on components in their use configuration, and that thermochemical methods be used for batch/lot qualification of materials.

Author Information

Janoff, D
Pedley, MD
Bamford, LJ
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Developed by Committee: G04
Pages: 60–74
DOI: 10.1520/STP17757S
ISBN-EB: 978-0-8031-5170-3
ISBN-13: 978-0-8031-1461-6