IP (Ingress Protection) ratings are standards for electrical enclosures as described in document 60529 issued by the International Electrotechnical Commission (IEC). The IEC is a worldwide organization for standardization comprising all national electrotechnical committees (IEC National Committees).
The objective of the standard is to classify degrees of protection of electrical equipment in terms of a) protection of the user against access to potentially harmful parts inside the enclosure, b) protection of the electronics inside against foreign objects, and c) protection of the electronics inside against water.
In the rugged computing industry, the rating refers to the equipment's ability to permit solids and liquids to penetrate the computer's enclosure. A mobile computer's IP Rating is expressed as a two-digit number (Example: IP-66). The first number designates protection from solids, while the second number designates protection from liquids. Please refer to the table below for specific IP rating information.
If a device is truly ruggedized for use in an industrial environment, then an IP rating will be specified. If a computer is being used in an environment where dust and moisture are prevalent, then the IP rating must be considered. If the IP rating is not specified, then you can assume a computer will not be resistant to dust and moisture. Any computer product being used in a truly industrial environment should have an IP rating of IP-65 in order to be fully protected from dust and liquids. Dust and moisture can cause major problems to internal computer components. Even if a device is not used in an industrial environment, it can become exposed to levels of dust and moisture that can eventually cause major problems.
It is important that manufacturers have their equipment certified by an outside laboratory to verify the product's IP rating. UL and CENELEC are two such laboratories, but many different laboratories exist that provide this service. The important thing is that the product is certified by an outside organization. If IP ratings are specified on a product's data sheet, then an approval certification number should also be included (Example: EN 60 529 or Approved to IEC 529).
Another important consideration is that every configuration of the product is IP certified, and not only one specific configuration. Many manufacturers will claim a certain IP rating, but this rating is only achieved with one specific, and usually expensive configuration. All available configurations should be IP rated for proper protection to allow the customer flexibility when ordering a mobile computer.
IP Rating Table
||SOLIDS (1st number)
||LIQUIDS (2nd number)
||Protected against objects > 50mm (hands)
||Protection against dripping water or condensation
||Protected against objects > 12mm (fingers)
||Protection against water spray 15 degree from vertical
||Protected against objects > 2.5mm (tools/wires)
||Protection against water spray 60 degree from vertical
||Protected against objects > 1mm (small tools)
||Protection against water spray from all directions
||Protected against dust, limited ingress
||Protection against low pressure jets of water
||Totally protected against dust
||Protected against high pressure water jets and heavy seas
||Protection against the effects of immersion (6 inches to 3.3 feet)
||Protected against immersion
(from "Can your rugged machine really handle the job?" by Tim Crews, published in Pen Computing Magazine issue #52, and edited by C. Blickenstorfer)