Downloaded from https://www.everyspec.com MIL-ST13-XM1 (SH) The following data, supplied by Stanton-Redcroft, shall give the temperature-flow rate relationship required to maintain a mean gm velocity of 4.0 cm/s about the lest specimen.
Temperature I:lowmctcr K (lJmin) 273 298 323 348 373 398 423 473 523 573 623 673 0 25 50 75 100 125 150 200 250 300 350 400 10.6 9.7 9.0 8.3 7.8 7.3 6.8 6.2 5.5 5.1 4.6 43 If the flow rate is held at 10.6 L/rein throughout this temperature range, the mean gas veloeity will vary between 4.0 cm/s at O ‘C (32 T) and 9.9 cm/s at 400 (750 40.5.2 Equilibrium The system shall ,be allowed to reach, flow xatehh,mm.+uilibriwm The test spccime~ pre-mounted in its holder, shall be placed in the column with the aid of a long W Mall@ ar,atlwr .appmpuhk% dmk= Tbe sample thammoumuple JewMdl beactw&.h tk base of the test specimen and about 30 seconds shall be allowed for the sample to reach equilibrium with the column environment.
40.53. Test initiation. The specimen shall be ignited and the testing is emducted in a manner identical to the ambient temperature oxygen index determination. 40.S.4 Average oxygen.index Once the proper oxygen-nitrogen mixture has been determined (equilibrium burning is sustained for 3 minutes or R 50 mm length) 5 to 10 speeimens should be tested to permit the calculation of a average value of the oxygen index at the temperature level of interest. 40S.5 Required maasummtants. Measurements of oxygen index shall be repeated until values have been obtained at 25 (ambient), 75, and 300 (75, 165 and 570 ‘F).
4fMi.6 Temperature index pro!k The average oxygen index values shall be graphed against temperahrte, and the best representative eurveshall be plotted through the data points to txmstruct the temperature index profile.