FED-STD-228A
3.1.5 Anhydrous calcium chloride.
3.1.6 Distilled water.
4. PROCEDURE
4.1 Unless otherwise specified in the detail specification, the specimen shall be immersed in water at 21°
± 1°C (70° ± 2°F) for a period of 22 ± ¼ hour.
4.2 The specimen shall be free from mechanical damage and shall not be bent or flexed until it has
reached room temperature. Handling and flexing of the specimen shall be reduced to the absolute
minimum necessary in testing.
4.3 The specimen shall be bent around a mandrel of the diameter specified in table I. If the size of the
wire or cable to be tested is size No. 2 AWG or smaller, as many turns shall be made about the mandrel
as will permit it to conform closely to the mandrel with a 2 to 2 ½-inch straight length of the specimen at
each end. The adjacent turns around the mandrel shall not touch each other and shall be 1/8 inch to ¼
inch apart. If the size of the wire or cable to be tested is larger than No. 2 AWG, a simple U-turn shall be
made about the mandrel.
4.4 The specimen shall be removed from the mandrel without disturbing its form, and shall be placed in
the desiccators over anhydrous calcium chloride for not less than 18 hours at room temperature. It shall
then be removed from the desiccators and weighed to the nearest 10 mg. within 3 minutes and the value
recorded as W1.
4.5 The specimen shall then be immersed in distilled water for the required period of time at the required
temperature with 1 inch ± 1/8 inch of each end of the coil or U-bend projecting above the surface of the
water. At the end of the immersion period the specimen shall be removed from the water bath, shaken
vigorously for 5 seconds to remove the adhering moisture, and weighed to the nearest 10 mg. within 2
minutes, and the value recorded as W2.
4.6 All fibrous coverings other than tape shall then be removed from the full length of the specimen. The
conductor, insulation, and tape, if any, shall then be weighed to the nearest 10 mg. and the value
recorded as W3.
4.7 The moisture absorption shall not be corrected for the portion of the specimen projecting above the
surface of the water.
4.8 If at any time the water in the bath becomes dirty or shows the presence of a surface film of dust or
wax, it shall be replaced with fresh distilled water.
5. RESULT
5.1 Calculation. The moisture absorbed by the fibrous covering of the specimen shall be calculated as
follows:
Moisture absorption, percent = W2-W1 x 100
W3-W2
240
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