Temperature and High Altitude (Low Air Pressure) Test
The Temperature and High Altitude (Low Air Pressure) Combined Test is to simulate the environments of air transportation, aerospace electronics, products with high pressure, motor, or pressurized, and high latitude countries. Experience from the field shows that the air flow in a low air pressure environment will slowly cause heat stress and temperatures on parts of the product will rise and often result in failure in functions, such as unstable motor function, and electrical arcing/ corona on high pressure components.
In order to accurately inspect and verify the product under the combined temperature and low pressure environment, International Electrotechnical Commission (IEC) has specified standards for preconditioning, post testing conditioning, temperature and air pressure changes. For example, in a low air pressure environment, the transfer of temperature is uneasy; therefore, if the pressure needs to be changed, the temperature must first be altered for the product to be exposed in the proper temperature setting, and then change the pressure.
Test applications can be divided into transportation environment and operating environment. Transportation environment testing usually is under low temperature with reduced pressure, and operating environment is under high/ low temperature with reduced pressure. In addition to simulating a real environment conditions, the test can predict failures during depressurization caused by the increased or induced mechanical stress from dynamic testing (vibration, shock) such as in a real situation. Hence, products in the designing stage should conduct dynamic testing prior to high altitude testing.
Common seen temperature and pressure effect:
Thermal heat/ portion overheat causing deformation or electrical failures, liquids or gas leakage, depressurization, deformation or cracks on airtight containers, unsteady motor or engine, electrical arcing or corona.