Downloaded from https://www.everyspec.com MIL-STD-810C ,. 10 March 1975 3.1.1 Measurements of test conditions. Al1 measurements of test conditions shal1 be made with instruments of the accuracy specified in 3.1.3. 3.1.2 Tolerance of test conditions. Unless otherwise specified, toler- ance of test conditions shall be as follows: a. Air temperature at the control sensor tl.4° C (*2.5“F). The equipment sensor response time (T) shal1 be 20 seconds or less. Temperature gradient across the cross-sectional area occupied by the test item shall not exceed 0.3° C (O.5“F) per foot in any direction, but never more than 2.2° C (4”F) total (equipmentnonoperating). b. Pressure:
When measured by devices such as manometers, *5 percent or *1.5 mu. (O.059 inch) of mercury, whichever provides the greatest accuracy. When measured by devices such as ion gages, *IO percent to 10-5 Torr. c. Relative humidity at the control sensor: *5 percent. d. Vib~ation amplitude: Sinissoidal: *1O percent Random: See Method 514.2. e. Vibration frequency: *2 percent, ~= fl/2 Hz belO~ 25 Hz. f. Acceleration: i10 percent. NOTE: (T) is the time required for the percent of a step change in temperature sensing system to respond to 62.3 in the measured environment. 3.1.3 Accuracy of test apparatus.
The accuracy of instruments and test equipment used to control or monitor the test parameters, shall be verified and shall satisfy the requirements of MIL-C-45662 to the satisfaction of the procuring activity. Al1 instruments and test equipment used in conducting the tests specified herein shall: a. Conform to laboratory standards whose calibration is traceable to the prime standards at the U.S. 8ureau of Standards. b. Have an accuracy of at least one-third the tolerance for the’variable to be measured. In the event of conflict between this accuracy and a requirement for accuracy in any one of the test methods of this standard, the latter shal1 govern.