Outdoor Digital Signage – Understanding NEMA Codes

The use of outdoor screens has increased in recent years. Advertising, information kiosks and outdoor digital signage are situated in various locations. From the high street to train stations, sports stadiums to ski resorts, digital signage screens are seemingly everywhere.

Part of this rise in the use of outdoor screens has been the falling cost and increased performance of the technology. LCDs are a fraction of the price they once were and now come in so many different varieties; with high brightness, high definition, waterproof, outdoor and other types of displays, continually hitting the market.

The need for a standard

With so many different types of LCD technology available, understanding the limitations of the devices can be difficult. For instance, a TV may be on display as waterproof, but can it be taken outdoors; alternatively, if you have a dusty or industrial location – what type of device would be suited there?

These questions and others are the reason why the National Electrical Manufacturers Association (NEMA) issue standards for electrical device enclosure to indicate the type of conditions they can operate in.

NEMA provide standards for outdoor enclosures

NEMA 4

For using outdoor digital signage or other outdoor screens, the standard that is most suitable for the level of protection required is NEMA 4 code. NEMA 4 devices are housed in an enclosure that are, “constructed for either indoor or outdoor use to provide a degree of protection to personnel against access to hazardous parts; to provide a degree of protection of the equipment inside the enclosure against ingress of solid foreign objects (falling dirt and windblown dust); to provide a degree of protection with respect to harmful effects on the equipment due to the ingress of water (rain, sleet, snow, splashing water, and hose directed water); and that will be undamaged by the external formation of ice on the enclosure.” (NEMA guidelines, www.NEMA.org).

Limitations of the NEMA standard

While this standard is useful for determining if a screen or LCD enclosure can operate in outdoor locations, it does have limitations. The NEMA code does not take into account factors such as temperature which in some locations across America can be extreme. These sorts of conditions can disable a device too. NEMA 4 devices may also be vulnerable to impacts, vandalism and other circumstances not covered by the NEMA standard.