Sunday, Aug 21, 2016 at 18:37
"Military grade quality", or "meeting military specifications", is a real catch-all, sales spiel, that doesn't tell you much at all.
The military set a range of specifications for equipment supplied to them. The U.S. have their own military specifications, the British have theirs, and NATO has more.
Each military specification covers a very intensive and comprehensive written and detailed range of requirements to be met.
Here are some of them ....
U.S. - MIL-STD-461, MIL-STD-1275, MIL-STD-810
British - DEF-STAN 61-5, DEF-STAN 59-411
In the case of MIL-STD-461, this specification covers covers the requirements and
test limits for the measurement and determination of the electromagnetic interference characteristics (emission and susceptibility) of electronic, electrical, and electromechanical equipment.
In the case of MIL-STD-810, this specification sets up specific
test processes to address a broad range of environmental conditions, that include: low pressure for altitude testing; exposure to high and low temperatures plus temperature shock (both operating and in storage); rain (including wind blown and freezing rain); humidity, fungus, salt fog for rust testing; sand and dust exposure; explosive atmosphere; leakage; acceleration; shock and transport shock; gunfire vibration; and random vibration.
As you can see, each military specification is intensive, but many are limited in scope to specific requirements.
MIL-STD-810 is probably the most comprehensive spec, and designed to
test the durability of the item.
Note that the
test processes in MIL-STD-810 are laboratory
test processes that don't necessarily relate to actual use, but are lab processes designed to find the durability of components.
Thus, they take, say, a bearing, and spray it with mud regularly, while they put a set heavy load on it, and spin it at a set speed, for a set period of time.
By doing this, they establish a process that replicates many in-field conditions, whilst setting a standard lab process for durability testing. This standardised
test process is then used on different products or brands, to see how they compare.
So, an item may be rated to meet one military spec - or it may be rated to meet multiple military specs. It all depends on the requirements of the end-use.
An alternator used on, say a genset engine, powering electronic or communications equipment, would be required to meet MIL-STD-461 - but not necessarily need to meet the durability standards of MIL-STD-810 - which durability spec would be needed on vehicles at the front line, doing serious off-roading.
The bottom line is - just saying "military grade" or "meets military specs", without quoting a specific military spec number, means very little.
Even if a military spec number is quoted, you would have to figure out if the military spec requirements apply to the style of useage you planned to use it in.
Cheers, Ron.
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