Downloaded from https://www.everyspec.com MIL-STD-81OC 10 March 1975 3.1.4 Stabilization of test temperature 3.1.4.1 Gperating. Unless otherwise specified, temperature stabilization will have been attained when the temperature of the part of the test item considered to have the longest thermal lag is changing no more than 2.O“C (3.6”F)per hour. Exceptions may occur on large test items. 3.1.4.2 Nonoperating.
Unless otherwise specified, temperature stabiliza- tion will have been attained when the temperature of the part of the test item considered to have the longest thermal lag reaches a temperature within 2.O“C (3.6“F) of the prescribed temperature, except that any critical com- ponent (e.g., battery electrolyte for engine starting test) will be within l° C (1.8”F). Exceptions may occur on large test items.
When changing tem- peratures, the temperature of the chamber air may be adjusted up to (9”F) beyond the desired end point for a period of time of up to 1 hour to reduce stabilizationtime, provided that the stabilizationrequirements of this paragraph are ultimately attained relative to the specified end point temperature, and provided the extended chamber temperatureswill not cause damage to the test item. .3.2 Performance of test 3.2.1 Pretest performance record.
Prior to proceeding with any of the environmental tests, the test item shal1 be operated under standard ambient conditions (see 3.1) to obtain data for determining satisfactoryoperation of the item as specified in the equipment specification,before, during and after the enviro~mental test, as applicable_. data shal1 be made to determine that the test .,item specificationrequirements. The pretest A record of specific pretest item performs within prime record shall also include the following, as applicable: a. The functional parameters to be monitored not specified in the equipment specification.
during and after the test, if This shall include accept- able functional limits (with permissible degradation) when operation of the test item is required. 3.2.2 Installation of test item in test facility. Unless otherwise specified, the test item shall be installed in the test facility in a manner that will simulate service usage, making connections and attaching instrumentationas necessary. Plugs, covers, and inspection plates not used in operation, but used in servicing shalI remain in place. When mechanical or electrical con- nections are not used, the connections normally protected in service shall be adequately covered.
For tests where temperature values are controlled, the test chamber shall be at standard ambient conditions when the test item is installed. The test item shal1 then be operated to determine that no function or damage was caused due to faulty installationor handling. mal- The s