Understanding ruggedised PC terminology

Edited by the Engineeringtalk editorial team Mar 4, 2005

Care in choosing a suitably rugged PC, be it a notebook, tablet or chassis, is crucial where it is envisaged the system is to be used outside the relatively benign environment of the office.

It is especially important to take care in choosing a suitably rugged PC, be it a notebook, tablet or chassis, where it is envisaged the system is to be used outside the relatively benign environment of the office.

A set of ratings have been produced to fix some definable standards, and so judgement can be made as to the suitability of a particular computer system to more rugged requirements.

This is commonly are defined in two forms: first the (military) MIL-STD-810E/F testing protocols for resistance to rain, humidity, salt fog, sand/dust, vibration, shock and temperature; and secondly IP (ingress protection) testing, which establishes the ability of an electrical enclosure to withstand penetration from solids (sand/dust) and liquids.

The military standard MIL-810E and F (F superseded E in January 2000) is a complex testing protocols for rain, humidity, salt fog, sand/dust, vibration, shock and temperature, among others.

This complexity does make it difficult to place in a nutshell all the various aspects of this stringent standard, rather it is best to concentrate on the its most relevant application to portable rugged PCs; that is drop tests and vibration.

For example, the MIL-STD-810E/F specification for mechanical shock, calls for notebook computers to withstand 26 drops, (one drop on each face/edge/corner with display screen closed, and unit powered off), onto 2in plywood over solid concrete without failure from a height of 1m.

Any computer successfully completing such a test is certified as MIL-810E/F compliant.

In the real world this set of circumstances will be unlikely to be repeated, but it does give a good indicator as to the suitability and likelihood of survival, after all many off-the-shelf high street computer systems can barely survive the general knocks in the office, let alone any kind of drop.

The MIL spec also defines resistance to vibration such as that from machinery or a vehicle.

Overall this means that a PC system with a MIL specification will almost inevitably have a longer life.

The IP rating looks at another aspect of environmental protection and describes the ability of an electrical enclosure to withstand penetration from solids and liquids, in real life most commonly dust and rain water.

Choosing a suitable IP level is a critical factor for electronic equipment, a two digit number after the letters "IP" uniquely determining the level of protection provided, the first digit giving the level of protection from solids, the second liquids.

A reference table that summarises the levels is provided on the DataQuest Solutions website.

If the PC system is to be used where there is any risk of liquid or dust contamination then choosing a system with a rating of at least IP54 is advisable.

Such a rating will allow outdoor operation, repelling rain water and wind borne dust to a high degree.

However where it is envisaged the system is to be used for several hours in heavy blowing rain, or the exterior deck of a ship a higher IP67 level should be considered.

For further advice on the above considerations DataQuest Solutions provides a number of portable rugged solutions, including notebook and tablet PCs.