Ruggedness Defined: Understanding IP Ratings and Military Standards
Mobile computers come in a variety of form factors – choosing the right one means matching the capabilities of the device to your application needs. For devices that must operate in extreme or challenging environments – in warehouses, freezers, oil rigs, delivery trucks, etc. – ruggedization is an important consideration.
But what does “rugged” mean when it comes to mobile computers? Just how rugged a device is can be determined via a number of technical specifications, including the device’s temperature tolerances, its Ingress Protection (IP) ratings, and whether it meets the requirements of the MIL-STD 810G standards.
Below we’ve explained the meaning behind standard IP and MIL-STD 810G ratings.
If a device is MIL-STD 810G compliant, that means it has been tested and certified to conform with the U.S. Department of Defense Military Standard.
The standard itself consists of 24 environmental tests designed to prove the device will survive a variety of conditions. Those tests range from temperature and humidity to vibration, immersion, acoustic noise, gunfire shock, solar radiation, and even fungus. The more methods tested and passed, the more rugged the device generally is.
For the MIL-STD testing to mean anything, you have to find out what testing methods were used for the certification.
No commercial organization or agency certifies MIL-STD 810G compliance, so manufacturers can create their own test methods. In some cases, that may skew the results. Be sure to verify the testing methods and obtain as much information as possible about testing conditions and parameters (do they match your application?), as well as who conducted the testing.
Ingress Protection (IP)
The IP rating specifies the level of environmental protection a device has against solids (dust) and liquids. IP ratings are defined by the IEC 60529 standard. The ratings are expressed as a two-digit number; the first number refers to protection against dust, and the second digit refers to protection against water.
The ratings are listed below.
First Digit (Protection Against Dust)
0: No protection
1: Solids larger than 50mm
2: Solids larger than 12.5mm
3: Solids larger than 2.5mm
4: Solids larger than 1mm
5: Protected against dust; limited ingress
6: Total protection against dust
Second Digit (Protection Against Water)
0: No protection
1: Dripping water
2: Dripping water (tilted)
3: Water spray
4: Splashing water
5: Water jets
6: Nozzle under pressure
7: Immersion (1 meter for 30 minutes)
8: Submersion (at depth, under pressure)
Why Is This Important?
Different levels of ruggedness are typically available for different types of application. Not every solution requires complete protection against dust or liquids.
For example, Zebra Technologies’ pocket-sized TC55 carries an IP67 rating against dust and water immersion, and meets the MIL-STD 810G spec for 4-ft. drops as well as applicable IEC tumble specifications. The Zebra MC-40 carries a lower IP rating of 54, but still meets MIL-STD specs for multiple drops.
The drop specifications under MIL-STD 810G also vary; some units are rated for 4-ft. drops, while others can sustain multiple 6-ft. drops to different surfaces at different temperatures.
Both of these standards are important because, in extreme operating conditions, the durability of the device can greatly reduce the total cost of ownership (TCO). The more rugged the device, the fewer failures you will experience in the field. That directly affects productivity and profitability.
There are other features that affect ruggedness and durability. Keypads should be fully sealed against dirt/liquid damage. Displays should be rugged enough to resist scratching and shattering if there is an impact.
I/O ports and peripheral connections can also represent a point of failure. Integrated features (like barcode scanners or credit card readers) are more durable than separate peripherals that have to be connected via a port or cable.
Determine your application requirements up front, and use that information to identify a mobile device with the right level of ruggedization for your environment. Doing so can ensure that your mobile employees can count on their mobile computers to remain operational even under the worst conditions.