Promoted Combustion (Promoted Burning) of Metals
This test is also known as Promoted Burning, Threshold Pressure tests and Metals Flammability testing. It is designed to determine the flammability of metal samples in pressurized oxygen.
The WHA promoted combustion test chamber is made from thick stainless steel pipe and internally protected with a copper sleeve. The chamber has a sight glass which permits visual access and video recording of the burning material.
The test system is also capable of testing at elevated temperatures and with a variety of gas phase diluents including supersaturated steam. WHA has the only promoted combustion facility in the world capable of producing and testing in oxygen/steam mixtures. ASTM G124 requires the test sample to be a 1/8" diameter rod as the standard sample size although a variety of geometries can be accommodated, such as: thin strips or thick rods and coupons (up to 20 mm).
For this testing, a small rod of the material is suspended in a test chamber which is filled with pressurized test gas. The chamber contains sufficient oxygen so that not more than 10% of the oxygen will be consumed when the material combusts completely. A promoter (typically aluminum or magnesium) applied to the bottom of the rod starts combustion of the material. If combustion of the entire rod occurs, then the test pressure is reduced and another rod is tested.
This procedure continues until self-sustained combustion of the rod does not occur for at least five tests at one pressure. The lowest pressure at which self-sustained combustion occurred is considered the threshold pressure for the material, and the difference between it and the highest pressure level that produced only incomplete combustion is the margin of potential error.
List of Standards
- ASTM G124
- NASA Test 17