Downloaded from https://www.everyspec.com MIL-STD-81OC 3.4 Procedure IV. Ground fire control and shipboard equipment. Step 1 - Prepare the test item in 3.2. accordance with General Requirements Step 2 - Dry the test item at a temperature of not less nor more than 50”C (122”F) for not less than 2 than 40”C (104”F) hours. Step 3.- Condition the test item at f5° C (77° t9° F) relative humidity for 24 hours. and 50 percent Step 4 - Take initial measurements as specified in the equipment specification in accordance with General Requirements, 3.2. NOTE: The test item may be readjusted or realigned as necessary to conform to the equipment specificationrequirements.
No further realignment or readjust- ment shal1 be permitted throughout the test period other than with accessible controls, external to.the tesk item, employed for operation of the test item. If repairs, replacement of parts, or adjustments other than by the accessible external controls are made at any time prior to completion of the measurements required at the end of the fifth cycle, all five of the 24-hour cycles shall be repeated. Repairs include any change to the test item that is not made by use of the accessible controls external to the test item. The test item shall only be operated when specified test measurements are being performed.
Step 5 - Subject the test item to five 24-hour cycles in accordance with figure 507.1-3. A 24-hour cycle consists of 16 hours at *5° C (140° f9”F) and approximately 8 hours at fS° C (86° t9° F) (include.transition times). The relative humidity shal1 be maintained at 95 percent, or greater, at both tempera- tures. Each transition time between 30° *5° C (86° i9° F) and ~5° C (140a +9”F) shall be not greater than 1-1/2 hours. The relative humidity during each transition need not be con- trolled.
Approximately 2 hours after stabilizationduring the high temperature and low temperatureportions of the first or second cycle, a sampling of the atmosphere in the chamber shall be made to determine that the conditions of temperature and relative humidity are uniform throughout the chamber. Measurements as specified in the equipment specification shall be made during the second cycle at 60° t5°C (140° t9°F) immediatelyprior to decreasing to 30° i5° C (866 f9”F). The test item shall be energized only a sufficient warmup and measurements specified in the equipment time to allow the required specification. 507.1-7 METHOD 507.1