In the second of our series examining what makes a rugged device, well, rugged, Sharon Clancy explores IP ratings...

IP environmental ratings along with MIL standards (MIL-STD) are perhaps the most widely recognised yet also perhaps the least fully understood of the standard definitions of what makes a mobile computer or tablet rugged.

Ingress protection is an important element in fit-for-purpose and Total Cost of Ownership considerations because it underpins reliability in the field.

You’ll also add weight, so potentially making it less appealing to your field workers.

In contrast, under-specify and you’ll be plagued by in-service unreliability and higher costs - not just of repairs but also those incurred by having technicians unable to carry out critical tasks.

As with all field service buying decisions, it’s a question of ensuring the mobile devices you select for your team are fit-for-purpose: reliable, user-friendly and able to cope with the demands made of them. And when it comes to environmental protection, it’s obvious that the device used by a technician fixing office equipment is less exposed to nature than a utility engineer working outdoors for much of the day.

There’s been lots written about the risks of under-specifying mobile devices for field service, but over-specification, particularly with IP ratings, is also widespread. It adds both unnecessary cost and can have a detrimental effect on productivity – taking us full circle back to the fit-for-purpose question.

“In the case of IP ratings, less can be more (peace of mind and money in your pocket) and excess protection is counter to the mission of mobile workers, as surely as too little protection will be. It’s a Goldilocks-type situation that can be resolved by having just enough.”

On the other hand, rugged device manufacturers warn against “rugged” versions of consumer smartphones and tablets – often delivered with the addition of a case rather than designing in protection from the start with components such as sealed keyboards and ports and enclosed internal components.

What the IP figures mean 

IP ratings are defined by International Electrotechnical Commission (IEC) standards and tell you how well devices are sealed against dirt and moisture ingress and the level of protection components have against whatever is thrown at them.

IP ratings have two numbers: the first indicates the degree of protection against dust, dirt and foreign bodies entering the device while the second is about how resistant the device is to the ingress of fluid from drops, sprays and submersion.

We’ve included a link to access a full IP ratings table at the bottom of the page, but for field service the numbers to look out for on a rugged mobile device are “5” and “6” for dust protection and 4,5,6, or 7 for water or fluid ingress. (In comparison, consumer devices typically have a rating of IP42 or lower.)

Both are important when assessing devices: if, like me, you’ve ever spilled tea or coffee on a computer keyboard, you’ll know that water ingress can be the kiss of death to electronic components.

Less dramatic but in the long term just as damaging are ingress of dust and dirt particles. They can cause keys to stick and generally penetrate causing damage to components.

While “6” is dust-proof, a “5” rating doesn’t mean the device will prove unreliable, just that it isn’t completely sealed against dust ingress.

It’s worth noting, too, that complete sealing against water and dust ingress may increase internal temperatures which in turn might impact on processor performance.

There are more numbers for fluid or water ingress: a “4” rating signals protection from splashes, “5” against water from a nozzle, “6” will cope with more powerful water jets or sprays, while “7” means you can submerge the device in water and it will still survive.

Again, which is best for your operations depends on the working environment - for many field-service environments, a “5” rating and even possibly a ”4 “will be perfectly adequate.

MIL-STD 810G

We’ll be taking a closer look at MIL-STDs later in this series, but we think it’s worth mentioning here that while most people associate MIL-STD 810G with drop and vibration checks, it also includes water-resistance and particle tests which tablet and notebook manufacturers also use to demonstrate the ruggedness of their products, especially in the ultra-rugged sector.

Unlike some computer manufacturers, says Panasonic, it does not shorten the duration of liquid resistance tests. For instance, for the Blowing Rain test, Toughbook fully-rugged computers are tested for a full 30 minutes per surface with a 70 mph wind at rainfall of 5.8in per hour.

Toughbook fully-rugged computers are tested for a full 40 minutes on liquid resistance. Although different Toughbook and Toughpad models have different levels of water resistance, all can survive 6oz of water poured on a keyboard.

Panasonic’s dust resistance test uses MIL-STD-810G, Method 510.5, Procedure I (Dust) and Procedure II (Sand), at up to 140°F, using both fine-grain silica flour and abrasive sand. To pass the test, a device must continue to operate with no binding or blockage of moving parts and no malfunctioning contacts or relays.

A testing question

While IP ratings do provide a standard for comparing devices from different manufacturers, some buyer caution is advisable.

Testing costs money, so some low-cost units may “conform” to IP65, for example, but may not have “passed” the required test or even been tested at all.

It’s also sensible to check how the testing was done – in-house by the manufacturer, or by an independent lab.

Getac, for example, uses a 3rd party to test its tablets and notebooks to ensure they are done to the full requirements.

Want to know more? Visit http://fs-ne.ws/10hVys to see full IP table

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