FED-STD-228A
Method 5231.1
18 APRIL 2014
FLAMMABILITY, SPARK METHOD
1. SCOPE
1.1 This method is intended for use in determining the flammability of flame-proof, heat- and flame-
resistant, and oil-proof wires and cables both with and without armor. It is particularly applicable to wires
and cables for use on shipboard.
2. SPECIMEN
2.1 The specimen should consist of a piece of the inspection unit approximately 18 inches in length.
3. APPARATUS
3.1 The apparatus shall be as follows:
3.1.1 Test chamber which shall be of sufficient size to contain the specimen, specimen support, heater
coil, spark plugs, flame travel gage, and other accessories. It shall be constructed so as to eliminate air
drafts and to permit a clear view of the interior through shatter-proof glass windows. Vent holes shall be
provided around the sides adjacent to the base to permit the admission of fresh air. An exhaust fan shall
be connected to the top of a capacity just sufficient to carry off smoke and gases.
3.1.2 The support shall be suitable for holding the specimen in a vertical position with an unsupported
span of not less than 14 inches.
3.1.3 Heater coils consisting of 7 turns of No. 10 (0.102-inch diameter) resistance wire, space wound
0.25 inch per turn. The nominal inside diameter of the coil shall be 0.5 inch greater than the overall
diameter of the specimen to be tested. The lower end of the coil shall be located 1.5 inches above the
top of the lower specimen support. The resistance wire shall meet the requirements of ASTM B344.
3.1.4 Two spark plugs with extended electrodes spaced 1/8 inch from the surface of the specimen shall
be located on diametrically opposite sides of the specimen and shall be placed with their longitudinal
centerlines in a horizontal plane ½ inch above the top of the heater coil in such a position as to ignite any
gases emitted from the heated specimen. A suitable electric circuit shall be provided to maintain
continuous sparking at electrodes during the test. The plugs shall be mounted in such a manner that they
may be moved away from the specimen after ignition takes place so as not to interfere with the travel of
the flame and to prevent the electrodes from becoming fouled.
3.1.5 A suitable flame travel gage for judging the distance of flame travel shall be mounted near the
specimen and in such a position as not to interfere with the travel of flame.
3.1.6 A constant current as required in table I shall be supplied from a suitable transformer source to the
heater coil.
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