Downloaded from https://www.everyspec.com MIL-STD-2031(SH) 40.2.2 CAUTION: A maximum sample mass d 8 grams shall be specified to reduce the risk of creating an explosive mixture. 40.2.3 Specimens, Test specimens shall be representative o[” the matcmals from which they are taken. Samples o[ composite materials and non-homugcncous assemblies must contain proportional quantities of each component. Whenever possible, the test specimen shall be a single piece of the same thickness as the material being tested. 40.3 Autoignition ternpemture. The procedure for determining the autoignition temperature shall begin with the cup furnace stabilized at 500 (930 “F).
One gram of the material shall be introdueal into the furnace. If autoignition does not occur, the process shall be repeated by increasing the temperature at 50 intervals until autoignition is observed. If autoignition occurs at 500 (930 ‘F), the furnace temperature shall be decreased in 50 increments until autoignition is not observed. At either temperature, additional teats shall be performed until the autoignition temperature is bracketed to within 25 If autoignition is not observed by 800 (1470 “F), then this shall be the maximum test temperature for the material.
40s.1 Note The electric spark or ethanol used to ensure immediate flaming of the material during toxicological testing in the flaming condition shall not be used while determining the autoignition temperature. 403.2 hmger sample. The observed autoignitimt temperature K dependent on apparatus, procedure, and sample size. A larger sampk may ignite at a lower temperature, so it is recommended that before actual testing begins, a larger sampie size (6 or 8 grams) be tested at the non-flaming temperature. Autoignition temperatures determined by this procedure may differ from Ihosemeaslmd meeorrlir@oASI?liD1929. ,, 40.4 Trial run.
For each new test material, a trial run without animals shall be performed using the non-flaming, flaming, or non-flnming/flaming transition modes as determined by the fire scenario of concern. This procedure shall determine: a. The degree of oxygen depletion during combustion of the sample b. mat the average chamber temperature over the 30 minute exposure period measured at the nose position of the animal does not exceed 40 (105 c. That the proper conditions have been established for conducting either non-flaming or flaming combustion exclusively.
40.4.4 Flaming tcs~ For the flaming test exposure, two drops of ethanol shall be added to the sample and an electrically heated wire or electric spark used to ensure immediate ignition of the test material 43