MIL-DTL-8777F
4.6.4.8.3 Flammability test procedure II. A specimen of completed wire of sufficient length shall be
suspended taut in a horizontal position within an enclosure which allows a flow of sufficient air for
combustion but is free from drafts. The tension applied to the specimen shall be sufficient to prevent
sagging of the specimen during application of the flame. A piece of facial tissue paper shall be
suspended taut and horizontal 9.5 inches (241.30 mm) directly below the cable and at least 0.5 inch
(12.70 mm) away from the table top. Melted or dripping material from the wire specimen shall fall on the
tissue paper. The top of the 2 inch (50.80 mm) flame of the top of the inner cone of the optional flame is
applied directly under the center section of the specimen for a period of 15 seconds for wire sizes 22
through 10 and 30 seconds for wire sizes 8 and larger. The stem of the burner shall be in a vertical
position and the flame spreader opening shall be parallel to the wire specimen. The position of the
apparatus in relation to the specimen shall be as specified on figure 1. Before removal of the gas flame
from the specimen at the end of the ignition period, a marking wire or indicator shall be placed
approximately 0.5 inch (12.70 mm) away from the wire, locating on the burning specimen the outer edge
of burning at each side of the flame. The rate of flame travel and self-extinguishing time shall be
measured from both indicating points. During the entire flame test, the Bunsen burner supporting rack
shall remain stationary.
4.6.4.9 Abrasion.
4.6.4.9.1 Abrasion procedure I. This test shall be performed on an abrasion testing machine
conforming to appendix A. One inch of the insulation shall be removed from one end of a 36 inch
(914.40 mm) sample of finished wire. The specimen shall be placed in the test machine and subjected to
the tension load specified in the applicable MS sheet. Using the weight support bracket and weight
specified in the applicable MS sheet, the sample shall then be subjected to the abrasion test. After each
reading, the specimen shall be moved forward 2 inches (50.80 mm) and rotated clockwise 90°. Eight
readings shall be obtained for each sample. An average shall be obtained by calculating the arithmetic
mean of all those readings for that wire which is individually less than the arithmetic mean of all the eight
readings per wire. This average shall define the abrasion resistance of the wire under test.
4.6.4.9.2 Abrasion procedure II. Previously untested specimens of wire, each 36 inches
(914.40 mm) long, shall be immersed in fluids as specified in the procedure specified in 4.6.4.6. After
removal from the fluids, the specimens shall be air-dried at 25° ±4°C for 24 hours and shall then be
subjected to procedure I as specified in 4.6.4.9.1.
4.6.4.10 Humidity resistance. A 52-foot sample of wire shall be subjected to the test specified in
4.6.4.10.2 for not less than 14 days, following which the wire shall be subjected to the test specified in
4.6.4.10.1 Apparatus. The apparatus shall consist of a test chamber capable of maintaining an internal
temperature of 71° ±2°C and an internal relative humidity of 95 ±5 percent. The test chamber shall be
capable of being sealed in order to retain the total moisture content in the test space. The heat loss from
the chamber shall be sufficient to reduce the internal temperature from the preceding operating
temperature too not greater than 38°C within 16 hours from the time of removal of the source of heat.
Distilled or demineralized water shall be used to obtain the required humidity.
17
For Parts Inquires call Parts Hangar, Inc (727) 493-0744
© Copyright 2015 Integrated Publishing, Inc.
A Service Disabled Veteran Owned Small Business