Basic Hot is applicable to many parts of the world, extending outward from the hot dry category of the southwestern United States, northwestern Mexico, central and western Australia, Saharan Africa, South America, southern Spain, and southwest and south central Asia. There are two climatic categories where high temperatures are typically encountered: Hot Dry and Basic Hot. However, climatic conditions should be considered. Identify the appropriate climatic conditions for the geographic areas in which the materiel will be operated and stored. Humidity is usually not a factor in high temperature testing. In general, companies will publish both storage and operating temperature specifications but rarely, if ever, tactical standby to operational for computers or LCDs. The term “tactical” is used to identify materiel that is not in storage, but is in a standby operational configuration, and as such is subjected to extended non-operational conditions immediately prior to operation.

Procedure III – Tactical Standby to Operational.

For the purposes of testing, time is allowed for the test item to stabilize in temperature. The limitations for 501.5 specify the Method is appropriate for short term (months as opposed to years), even distributions of heat throughout the test item.

Thus, a manufacturer stating their device has been tested per Mil-Std-810G for operation between 0 and 50 deg C has written their own test method. There is no specification delineating a maximum temperature of 50 deg C, for example. With a few exceptions, the Methods for temperature do not place absolute limits on the devices to be tested.

The screen on LCDs can turn black at elevated temperatures.

Intermittent operation as power supply modules shut down in a protective mode.

Intermittent operation as the processors automatically slows down in a protective mode.

Exceeding operating limits on components inside the power supply such as transformers.

Exceeding the published high temperature limits for the components such as processors and chip sets causing damage.

High temperature effects on computers and LCDs include:

Method 501.5 covers 12 pages of Mil-Std-810G. Methods 502.5 and 520.3 will be examined in future blogs. Method 520.3 details testing which combines temperature, humidity, vibration and altitude interactively. 810G covers temperature in 501.5 (High Temperature), 502.5 (Low Temperature) and 503.5 (Temperature Shock). This is Part 3 of a series delving into the intricacies of Mil-Std-810G.

Lightwright 6 high temperature