The International Protection Rating System (IP code) often referred to as Ingress Protection Codes, are a standardisation system that governs the protection offered by electrical enclosures to provide more accurate information than the vague terms of dustproof and waterproof.
Commonly used throughout Europe (the National Electrical Manufacturers Association NEMA promote standards in the USA) as defined in international standard IEC 60529 (International Electrical Commission). The IP rating is a two digit code indicating the type of conditions the enclosure can operate in.
The two digits of the IP rating specify both protection from solids (the first number) and protection from liquids (the second digit). The first digit ranges from 0 (zero), which offers no protection from solid objects to 6, indicating total dust tight protection, with the numbers in between, indicating smaller and smaller particulate protection.
The second digit of the IP code, which indicates the protection afforded against liquids, also starts at zero, where no protection against liquids are offered all the way to number 8, where the enclosure is completely water tight and can even be immersed without suffering leakage.
A full breakdown of the IP ratings can be seen in the charts below.
Often people think for outdoor digital signage use, an LCD enclosure would need to have the maximum amount of protection possible; however, due to the need of LCD screens to have a direct airflow, to prevent overheating and provide cooling, this total sealing against water and dust is impossible.
Indeed, this sort of protection is also unwarranted. When using an outdoor enclosure, perhaps for digital signage, the protection required is only from rainfall and other weather elements.
As rainfall falls down and is at a low pressure then the type of protection required for an outdoor enclosure is around the IP54-IP65 range. An enclosure within these limits will be able to operate in outdoor locations no matter what the weather and will ensure the screen is not only protected from rain and other weather but also airborne particles, dust and pollution.