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As we continue our series decoding the language used by rugged hardware manufacturers we turn our attention to one of the most widely cited certifications MIL STD 810G

Almost every rugged device you see will proudly boast the magical code MIL STD 810G somewhere in the specs but what exactly does it mean and why is it just so important?

Well as you may well have guessed MIL STD is actually short for Military Standard (the artwork was probably a give away wasn’t it?) In fact it is an American military standard that although has it’s origins with the US Air Force is now upheld in a tri-service agreement between the US Army, US Navy and US Air force. However, the standard is widely adopted amongst commercial products that need to be able to hold up to rigorous environmental tests.

The G if you were wondering relates to the current revision of the certification document and we have been at G since 2008.

General Program Guidelines

The first part of the MIL-STD-810G is a set of general guidelines that describes management, engineering, and technical roles in the environmental design and test tailoring process.

It focuses on the process of tailoring design and test criteria to the specific environmental conditions an equipment item is likely to encounter during its service life.

Laboratory test methods

The second element of MIL-STD-810G is focussed on the environmental laboratory test methods to be applied using the test tailoring guidelines described outlined in the general program guidelines.

With the exception of Test Method 528 (Mechanical Vibrations of Shipboard Equipment), these methods are not mandatory, but rather the appropriate method is selected and tailored to generate the most relevant test data possible.

Each test method also supports the test engineer by describing preferred laboratory test facilities and methodologies. These environmental management and engineering processes can be of enormous value to generate confidence in the environmental worthiness and overall durability of equipment and material.

 

However, it should be noted that there are always limitations inherent in laboratory testing that make it imperative to use engineering judgment when comparing lab results to how a device may cope in real world environments as in many cases, real-world environmental stresses (both singularly and especially when combined with other stresses) cannot be duplicated practically or reliably in test laboratories.

That said the MIL STD 810G is accepted as a global standard when it comes to the robustness of rugged devices.

The tests themselves are varied across a range of different environmental stresses which include:

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• Temperature ranges
• Shock
• Vibration
• Humidity
• Salt fog
• Explosive atmosphere

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As well as a number of other environmental stresses. However, a device can be tested and certified as MIL STD 810G for each and any of these tests individually and they are not mutually dependant on each other. So for example a device could be tested to MIL STD 810G for shock (test 516) only without having to be able to pass any other MIL STD 810G criteria.

In terms of rugged devices suitable for field service perhaps the most important of these tests (and the most likely you are going to see in manufacturers spec sheets) are Shock, Operating Temperature, and Vibration. There are MIL STD 810G tests for sand and dust ingress as well as contamination by fluids but generally most manufacturers stick with the IP rating system for these areas.

Test 516: Shock

Almost certainly the most widely cited of the MIL STD 810G tests by rugged manufacturers, this test method is often referred to as the “drop” test as it gauges how well a device holds up to impacts while falling from certain heights.

The tests are designed to find out just how much general physical abuse a device can take while in operation and there are eight different procedures to choose from that each use different ways to cause shock or impact but of these the most common is procedure IV.

 

Just how extensive the test is down to a devices weight but generally tablets, phones and laptops all fall into the first category (weights of less than 100 pounds and lengths of less than 91 cm). The devices are dropped from a height of 4ft onto each of it’s six faces 12 edges and 8 corners onto two inches of plywood over concrete (which apparently is the most common surface a device is likely to land on). Testers then visually inspect for damage and determine whether the device still works after each drop.

Tested to. Vs. Engineered to

One problem with MIL STD 810G testing is that it can be very expensive and it’s important to remember that MIL-STD-810 is not a specification per se but a standard. A specification provides for absolute criteria which must be satisfied to “meet the spec”. MIL-STD-810 as a standard provides methods for testing material for use in various environments but provides no absolute environmental limits.

Therefore, some OEMs will skip the whole second part of MIL STD 810G (the actual testing part) yet still claim their devices are engineered to meet MIL STD 810G standards.

Whilst such devices may well be more than capable of surviving the rigours of your field engineers toughest day, the simple fact is that they haven’t been actually tested to do so.

That said most of the dedicated rugged players within the space such as Getac, Panasonic and Xplore et al will all have their own internal testing facilities and will also often engage with a third party to validate their findings.

What MIL STD 810G does do however, particularly when it comes to the ‘drop test’ is give you a base line understanding of what you can expect your field service engineers shiny new tablet etc to withstand.

 

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