Rugged computing terminology and standards
(by Conrad H. Blickenstorfer)

What's an IP rating? Ingress Protection? How is that measured, and what does it mean? What does "intrinsically safe" mean? How do they do drop tests and such? Where can you find information on testing procedures? What are NEMA ratings? What does RoHS mean, and is it important? (Yes, especially if you deal with European markets). And what's FIPS 201? Or does a client request adherence to IEC 60601? Or what does a vendor need to do to comply with MIL-L-85762A for night vision imaging systems?

All of these terms, and more, you'll encounter in ths specifications and sales pitches of rugged computing equipment. Knowledge of what it all means is crucial to understanding the potential suitability of equipment for your applications, and also when discussing your needs with a vendor.

In this section you'll find explanations of the many definitions and terms used in rugged computing, and also information on the various rating systems employed to indicate ruggedness, sealing and other environmental protection. You'll also find descriptions and updates on enabling technologies, such as outdoor-readable notebook computers screens.

You also find primers of a variety of ancillary technologies, such as RFID, bar code scanning, and others. What you see now is just the beginning. Over time we'll be adding additional definitions, primers, and white papers.

Vendors: If you have Technology White Papers which you'd like to share with potential clients, please email us at cb@pencomputing.com.

At RuggedPCReview.com we consider the Ingress Protection rating to be especially important. It tells you whether dust or water can get into your computer. Below is the IP rating table.

IP (Ingress Protection) Rating Table

	SOLIDS (1st number)		LIQUIDS (2nd number)
0	No protection	0	No protection
1	Protected against objects > 50mm (hands)	1	Protection against dripping water or condensation
2	Protected against objects > 12mm (fingers)	2	Protection against water spray 15 degree from vertical
3	Protected against objects > 2.5mm (tools/wires)	3	Protection against water spray 60 degree from vertical
4	Protected against objects > 1mm (small tools)	4	Protection against water spray from all directions
5	Protected against dust, limited ingress	5	Protection against low pressure jets of water
6	Totally protected against dust	6	Protected against heavy seas
7	N/A	7	Protection against the effects of immersion (6 inches to 3.3 feet)
8	N/A	8	Protected against immersion

What's MIL-STD-810F Method 506.4 (Rain)?

Manufacturers often refer to MIL-STD-810F Method 506.4. The MIL-STD-810F is a Department of Defense document that describes test methods for environmental engineering considerations and lab tests in great detail. Method 506.4 describes testing to determine how well a piece of equipment is protected from rain, water spray, and dripping water.

Procedure I tests resistance to rain and blowing rain, with variations up to 45 degrees from the horizontal.

Procedure II sprays all exposed surfaces with water for not less than 40 minutes per face.

Procedure III drips water from no less than 3 feet for 15 minutes.

What's MIL-STD-810F Method 509.4 (Salt Fog)?

Salt fog can quickly ruin equipment. 509.4 describes testing methods to determine the effectiveness of protective coatings and finishes on materials for corrosion, electrical effect and physical effects. It can also determine the effects of salt deposits on the physical and electrical aspects of materiel. The product is exposed to salt fog mist from a 5% salt solution via atomizers at about 95 degrees Fahrenheit for a minimum of four alternating 24-hour periods, two wet and two dry. The product is then examined for salt deposits that can clog or bind components, electrical malfunction, and potential short and long-term impact of any observed corrosion.

What's MIL-STD-810F Method 510.4 (Sand and Dust)?

Specs also often include references to MIL-STD 510.4. Those are tests that evaluate the ability to resist the effects of dust that may obstruct openings, penetrate cracks, crevices, bearings, and joints and to evaluate the effectiveness of filters.

Procedure I tests if the device can keep out blowing dust.

Procedure II determines if it is sealed against blowing sand.

Procedure III tests what happens if dust settles on the computer as that can affect heat dissipation or clog up filters.

What's MIL-STD-810F Method 516.5 (Drop)?

MIL-STD-810F 516.5 also often appears in ruggedness specs. This tests a device's ability to survive a variety of impacts and shocks. Procedure IV -- Transit Drop -- is especially popular and commonly called "drop test" or "drop spec." The test requires that items weighing 100 pounds or less survive a total of 26 drops on each face, edge and corner. The 26 drops an be divided among up to five samples of the same test item. Drop distance generally depends on how a device is commonly used in the field. A mobile computer might typicall drop from about 48 inches when it falls while being operated. According to the DOD, field data suggests that a typical piece of equipment will be dropped from heights up to four feet an average of four to six times during its life cycle.

What other MIL-STD-810F tests are there?

The MIL-STD-810F is a very comprehensive document. As a result, a statement saying a device is "MIL-STD-810F tested" doesn't provide enough information. The MIL-STD-810F is an almost 600 page document with tests for about two dozen things that can affect a piece of equipment. The tests are:

• 500.4 Low Pressure (Altitude)
• 501.4 High Temperature
• 502.4 Low Temperature
• 503.4 Temperature Shock
• 504 Contamination by Fluids
• 505.4 Solar Radiation (Sunshine)
• 506.4 Rain
• 507.4 Humidity
• 508.5 Fungus
• 509.4 Salt Fog
• 510.4 Sand and Dust
• 511.4 Explosive Atmosphere
• 512.4 Immersion
• 513.5 Acceleration
• 514.5 Vibration
• 515.5 Acoustic Noise
• 516.5 Shock
• 517 Pyroshock
• 518 Acidic Atmosphere
• 519.5 Gunfire Vibration
• 520.2 Temperature, Humidity, Vibration, and Altitude
• 521.2 Icing/Freezing Rain
• 522 Ballistic Shock
• 523.2 Vibro-Acoustic/Temperature