Heat Effects of Promoters and Determination of Burn Criterion in Promoted Combustion Testing

[摘要] Promoted ignition testing (NASA Test 17) [1] is used to determine the relative flammability of metal rods in oxygen-enriched atmospheres. A promoter is used to ignite a metal sample rod, initiating sample burning. If a predetermined length of the sample burns, beyond the promoter, the material is considered flammable at the condition tested. Historically, this burn length has been somewhat arbitrary. Experiments were performed to better understand this test by obtaining insight into the effect a burning promoter has on the preheating of a test sample. Test samples of several metallic materials were prepared and coupled to fast-responding thermocouples along their length. Thermocouple measurements and test video were synchronized to determine temperature increase with respect to time and length along each test sample. A recommended flammability burn length, based on a sample preheat of 500 F, was determined based on the preheated zone measured from these tests. This length was determined to be 30 mm (1.18 in.). Validation of this length and its rationale are presented.

[发布日期] 2010-05-19

[学科分类] 机械工程学