MIL-DTL-24640C
4.7.14.4 Observation. Specimen failure shall be construed if the collected water volume exceeds that shown in
table XVII.
TABLE XVII. Limits for water leakage.
Sum of specified cross-sections of all specimen
Collected water volume
conductors (see 3.1)
(cubic inches, maximum)
(circular mills)
Less than 9,001
4
9,001 to 15,000
5
15,001 to 25,000
6
25,001 to 50,000
7
50,001 to 100,000
8
100,001 to 200,000
10
200,001 to 500,000
11
500,001 to 800,000
12
800,001 or greater
13
4.7.15 Acid gas generation. The method given below is to determine the total emission of any strong soluble
acids (pH less than 3). The required apparatus is shown on figure 10. A weighed sample of the jacket, fillers, and
insulation materials (for component wire, use insulation removed from a 22 AWG wire), normally ¼ to ½ gram,
shall be placed in a silica boat which is put into the center of a silica tube, length 50/60 centimeters and internal
diameter 20/22 millimeters. The materials shall be tested individually. The silica tube shall be placed in the tube
furnace. An air supply, derived from a blower or compressed air cylinder, at the rate of 1 liter per minute ±5 percent
shall be passed through the silica tube and then through four absorber flasks each containing 30 milliliters of
deionized water. The furnace heating shall be commenced and the temperature of the tube and sample shall be
raised to 800+10 °C over a period of approximately 40 minutes and then held at temperature for a further 20
minutes. During the heating period, any acid gases produced will be carried over into the absorber flasks. On
completion of the heating cycle, the acid content of the fluids in the absorber flasks shall be titrated against 0.1 N
sodium hydroxide solution using Congo red as an indicator. The total titrate indicates the total soluble acids. 1.0 ml
of 0.1 N sodium hydroxide solution is equivalent to 3.65 mg of acid expressed as "acid equivalent relative to
hydrochloric acid."
4.7.15.1 Observation. Specimen failure shall be construed if the acid equivalent exceeds the percentage, by
weight of the sample, specified (see 3.1).
4.7.16 Halogen content. The halogen content of the cable jacket and fillers shall be determined by X-ray
fluorescence or analytically following an examination and analyses of the chemical composition of all ingredients
used.
4.7.16.1 Observation. Specimen failure shall be construed if the halogen content is greater than that specified
(see 3.1).
4.7.17 Smoke index. The smoke index shall be measured as specified in Defence Standard 02-711 with
4.7.17.1 Specimen.
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