The workers in the field may simply need something that can be used in a truck, of they may leave their trucks and need something that can survive in the wild - surveyors and foresters are good examples.
But these units typically cost at least twice as much as the commercial-grade devices available in computer stores. (Some, shielded by only a rubber cover, may be only a few percentage points higher.) Are they worth it?
'In many applications, the ruggedized units were more cost-effective,' said Tim Shea, analyst at Venture Development Corporation, a market research firm, who studied the matter recently. Basically, the failure rate of the commercial units, used in industrial or other harsh environments, was three times (or more) higher than ruggedized units. The commercial units had a failure rate of 29 percent or more per year, while the ruggedized ones failed at a rate of five to 10 percent yearly, he said. Meanwhile, commercial units may only have a one-year warranty, and the LCD screens are typically not covered at all by the warranty. Meanwhile, the worker whose unit died is unproductive until a new one is brought on-line.
On the other hand, 'Interesting studies have found that hardened machines don't last that much longer in the field,' said Rob Enderle, head of the Enderle Research Group. 'Users abuse the hell out of them (the ruggedized devices) - throwing them in puddles and kneeling on them - while taking care of the commercial devices. And they are a lot heavier, which means they are often shipped with luggage on an airline rather than being carried on (with the passenger.) But the screens are susceptible to rapid pressure and temperature changes, which means they will often split. It's difficult to harden them against that.
'In rough environments you might see a 30 percent loss of commercial units as opposed to 20 percent for the hardened units. Increasingly, they are deciding that the difference in price is not worth the additional ten percent survival rate. But I am talking about units that are taken from a truck to a job site, not ones that are taken into the field - or the battlefield - where a commercial unit might die in 15 minutes,' Enderle noted.
On top of that, the performance of hardened units tend to be slower than commercial units, Enderle added, since the processor has to run slow to avoid over-heating. Using a fan would open the unit to the outside, and defeat some of the ruggedization. Experiments using water cooling, with the case of the unit housing a radiator, show promise, he noted.
The degree of ruggedization is usually expressed as an IP (intrusion rating) number (at least in North America.) There are two numbers in the rating, the first for dist protection and the second for moisture protection.
For the first number (dust or solid object protection), the scale looks like this:
0: No special protection against intrusion by solid objects
1: Protected against solid objects greater than 50 mm in diameter
2: Protected against solid objects greater than 12 mm in diameter
3: Protected against solid objects greater than 2.5 mm in diameter
4: Protected against solid objects greater than 1 mm in diameter
5: Protected against dust
6: Dust-tight
The second number (concerning protection against liquids) looks like this:
0: No special protection against moisture
1: Protected against dripping water
2: Protected against dripping water when tilted as much as 15 degrees from a normal position
3: Protected against spraying water
4: Protected against splashing water
5: Protected against a jet spray
6: Protected against a heavy jet spray
7: Protected against immersion
8: Protected against submersion
The difference between immersion and submersion was unclear, but immersion appears to mean that the unit can be temporarily covered in water, while submersion appears to mean that it can operate under water for extended periods.
Therefore, a rating of (for instance) IP67 means complete dust-proofing and resistance to immersion in water. Sources agreed that IP 68 is never seen, there being no market demand for it (outside marine equipment, where it's assumed.)
Shea indicated that the 'sweet spot' in the market is IP54, which is adequate for use in warehouses.
Vendors also often give impact-resistance rateings their units indicating how far they can be dropped onto a wood-covered floor. Four feet seems to be about the average claim, and that is about how far a person would drop it if the unit fell out of his hands.
A very small (but insistent) market niche also demands units that are 'inherently safe,' meaning they can be used in the presence of explosive gas without generating a disastrous spark.
Lamont Wood