Great article by Peter Kaszycki
To successfully deploy digital displays in outdoor environments, many factors must be considered.
By Peter Kaszycki
With indoor environments, everything is nice and comfortable. It does not rain inside, temperatures and humidity are controlled, the sun does not shine indoors, ambient light conditions do not change, the air is clean, power is consistent, the wind does not blow and vandalism is rare. Basically, digital displays that are deployed indoors are in a controlled environment in virtually every respect.
However, with outdoor environments, everything changes – and it changes dramatically. Outside, digital displays are in an uncontrolled, harsh environment that is constantly changing, meaning anything can happen to them. Therefore, it’s important to consider the following factors before choosing and deploying outdoor digital displays:
|Temperature||65 to75°F||-20 to 110°F|
|Humidity||Under 30 %||Over 80%|
|Rain, snow, dust, dirt||None||Yes|
|Brake dust, fumes||None||Yes|
|Wind Load||None||Yes – up to 140 MPH|
|Ambient Light||Same all day||Changes throughout the day|
|Duty Cycle||8-12 hours/day||16-24 hours/day|
The table above shows just what severe conditions outdoor digital displays have to endure. They must be built to withstand direct sunlight, extreme temperatures and humidity, rain, snow, dust and dirt, harsh windy conditions and also be protected from vandalism. It’s imperative to keep all of the above factors in mind when evaluating outdoor displays. But, now that I’ve covered the range of considerations that must be thought over prior to purchasing and installing outdoor displays, let’s take a deeper dive into one specific factor – the impact of the sun.
Before placing displays in direct and indirect sun conditions, consider that:
- Sunny environments require high-bright displays for optimum viewing;
- Display’ luminance should normally be between 1,500-2,500 nits or candelas;
- Brightness should be measured through cover glass/film, not just at the surface of the LCD;
- Versions that maintain set brightness levels over time are preferred;
- Some displays will lose 10-12 percent brightness/year;
- Some displays will lose 10-15 percent brightness in hot or cold ambient conditions;
- Solar Clearing of the LCD screen is a concern. With direct sunlight, the LCD crystals could go through a phase change and cause black blotches on the screen.
- Some LCDs are rated at 68°C, others 80°C and some at 110°C. The higher rating, the better.
- Solar Clearing will reduce the operating life of the displays.
- CCFLs are not recommended for outdoors. Only use LED backlight systems.
- Avoid digital displays that are optically bonded to cover glass.
- The sun is worse in winter with clear skies/lower haze.
- Employ ambient light sensors to automatically adjust brightness based on light conditions.
- East/West orientations are worst. North/South orientations are best.
- Rising and setting sun are the worst times of the day, not high noon.
There is a great deal to consider when thinking of how the sun alone will impact outdoor displays. But also consider the following when it comes to the impact of temperature and humidity on outside digital displays.
- Be designed for temperatures down to – 20°F and over 110°F.
- Be designed to be based for high temperatures and direct sun load.
- Have a display that is “sealed” to prevent condensation forming inside the cover glass.
- Have a start-up procedure for low-temp power up; at -20°F
- Have a start-up procedure for high-temp power up; at +110°F
- Have a plan for when the display is not to be run. Consider just turning off the backlight, not the entire digital display
- Have embedded electronics (player, modem, etc.) that are rated for internal display temperatures.
- Have a plan for cooling. Conventional A/C systems will drip, require maintainance and consume significant power. Consider alternative cooling methods.
- Have a plan for heating when operating in freezing conditions
- Be prepared for how temperature fluctuations can affect brightness.
While the considerations related to sun, temperature and humidity may seem overwhelming, once they are factored into your outdoor display purchase and deployment, you can rest easier knowing you have taken every precaution to protect your investment. Beyond environmental conditions, also mull over installation, operational and service conditions.
Ask yourself these questions:
- Are there any city/state permits required?
- Does the mounting need to be certified by a Professional Engineer?
- Must design digital display AND mounting structure for wind loads. Have you thought about Gail winds, hurricane force?
- Are Unions/safety personal required for installation or for service?
- How is power to be run to the unit?
- How is connectivity to be achieved? Consider 3G Modem/Antenna.
- What is the cellular service like for the area?
- What are the restrictions relative to full-motion video content?
- What are the restrictions relative to type of transition, frequency of transition?
- What are the codes/requirements for auto-dimming/shut-down at night?
- What power is available? Consider displays with a universal power supply of 85 V to 265 V.
- Who will be paying for power? Outdoor displays consume three to five times more power than indoor.
- Consider brown-out conditions in summer. Current draw will spike and may trip breakers.
- Most outdoor displays run 18-24 hours/day. Is your display designed for this duty cycle?
- If unit is to be “turned-off” at night, consider just turning off backlights and not entire display.
- What type of cover/safety glass will be used? It must resist breakage
- The glass should have an anti-reflective (AR) coating to reduce reflections from eight percent to under two percent. (AR coating helps with reflections from buildings, cars, and direct sun.)
- Glass should be separate from LCD screen. That way you can replace glass without replacing LCD.
- Can the digital display be serviced in the “installed” position?
- How easy is the service and will repairmen be working in outdoor conditions (cold, rain, wind-blown dust)?
- How modular are the replacement components?
- How intelligent is the display? Can it verify that the image is being displayed on the screen?
- Can the display report back to the NOC operational data and alerts?
- Can the display be controlled and updated remotely?
- Can the embedded player, 3G modem and switch be automatically or remotely re-booted?
- Provisions for mini-UPS system so unit can “phone home” if it experiences a failure?
- What is the “sealing” rating of the display? NEMA 3, IP 65, etc. Will it be washed down?
- How is the unit protected from insects, rodents?
- Does the paint finish provide protection against harmful UV rays over time?
Other considerations for outside displays:
- Some cities do not allow for full-motion video, while some cities do.
- Also, cities may only allow for digital static ads and then they may or may not allow for transitions from one ad to another.
- If your area allows for digital static ads, then you may only be allowed to change the ad every 10-15 seconds or 30 seconds.
- Some cities do not allow for the digital side to be facing traffic, like a Bus Shelter application. It has to be opposite the traffic flow as to not distract drivers.
- Many cities have nighttime restrictions requiring the display to be dimmed down at night or turned completely off after 11 p.m.
Though there are many considerations and questions that come with properly deploying outdoor high-bright digital displays, the benefits of reaching the OOH (Out Of Home) marketplace are significant. It’s worth the time and thought to carry out your deployment after taking all points suggested here into consideration.
In summary, remember that:
- True outdoor digital displays are NOT re-packaged indoor displays.
- The environmental conditions are significantly harsher than indoor conditions and are every-changing
- The sun is the #1 enemy of Digital Displays.
- Common failure points include overheating, solar clearing, fading brightness and insufficient power.
Peter Kaszycki is president and CEO for Alpharetta, GA-based LG-MRI, which provides indoor and outdoor digital displays ranging in size from 47 inches to 84 inches. He can be contacted via email at [email protected].