The MIL-STD-810F specification requires that power supplies for military applications conform to a broad range of environmental conditions.
These conditions include low pressure for altitude testing, exposure to high and low temperatures, freezing rain, humidity, fungus. And the list goes on. While more power suppliers are pushing to adhere to this standard, perhaps they should be aware of some rather worrying limitations. Tests are taken under laboratory conditions to recreate severe military conditions - however, many of these cannot be accurately replicated in test laboratories. Therefore, although a system or component may pass laboratory tests, this doesn't necessarily mean it would also pass field verification trials. Great for the company awarded the specification - not so good when an inferior component fails to work during a military operation. It would be nice to think that power suppliers strive to not only conform, but exceed the required specifications. However, there is a fine line between integrity and profit.