As you scan the wide variety of LED products available and have that spec sheet staring at you, just what is it trying to tell you? With all the documented terms, it can be confusing to figure out what everything means and how those measurements will affect your sign. But taking the time to read and learn the basic principles of a spec sheet will arm you with key information that will help you to determine the best LED product to fill your needs.
Think of a spec sheet as an all-inclusive fact sheet, suggests Jill Bonilla, marketing manager of SloanLED.
By reading a spec sheet, you can tell exactly how bright your sign will be. Photo courtesy of SloanLED.
“I think that people need to be able to find what the product does. It’s kind of like a fact sheet in one place. What is the voltage? What size is the module? Can I use it in a small application? What colors does it come in?”
For instance, one particular LED product line may offer a full color range, says Bonilla, while another series from the same manufacturer only provides white LEDs. As basic as it sounds, diligently inspecting your LED spec sheet will tell you anything and everything you need to know.
SPEC SHEET PRINICPLES
When examining your spec sheet, the lumens-per-watt figure is key, says Chris Smit, chief technical officer of US LED. Lumens per watt measures the product’s ability to convert energy to light. Basically, this figure tells you the LED’s efficiency. Keep in mind, the higher the number, the more efficient that LED is, says Smit. And that higher efficiency means a cost savings on energy.
The color temperature is another important metric, which measures the hue of a specific type of light source. By identifying the color temperature on the spec sheet, says Kirk Fowler, Western region sales manager of Sylvania, you will ensure your that your LEDs are all of the same illumination. Color temperature is measured in Kelvins.
Spec sheets will help you understand what product is best for your needs. This sign was designed, fabricated and installed by Excellent Signs located in London, Ontario. Photos courtesy of SloanLED.
“Within an LED module, you want to have every LED chip be at the same measurement—say, 2700 K—so they all look the same. Where you get into inconsistencies is when you have a 2700 K LED right next to one measuring 3300 K,” says Fowler.
This concept is true for colored LEDs, as well, but the metric to look for on the spec sheet is based on the wavelength, which is listed as nanometers, says Fowler. To ensure your LEDs are at a matching color temperature or wavelength, look for the product code, which sorts the modules based on those measurements. However, Smit says the exact measurement is dependent upon the end user’s preference.
If you are planning on installing a high-rise application, Eric Stevenson, global product manager of signage of GE Lumination, suggests looking for a remote power-supply option on the spec sheet, which allows the unit to be fixed in a convenient location.
This sign was fabricated by SignArt in New Mexico, using Sylvania LEDs. It was purchased through New Mexico Sign Supply. Photo courtesy of SignArt.
“Let’s say you have a channel letter sign that is placed 20 stories high on a building, and you are not able to remote-mount the power supplies to the LED system. Instead, your power supply would more than likely have to be placed inside the letter, which usually is the weakest point of the LED system,” explains Stevenson. “Somebody would have to hire a crane, or somebody would have to send someone up to take the face off the letter to change the letter.
But, instead, if that installer could remotely mount the power supply, then maintenance or repairs could be controlled by an accessible unit.
Of course, avoiding those incessant trips to the power supply is ideal for any installer, so Smit recommends finding an LED that provides acceptable lumen maintenance, meaning the lifetime expectancy of the module. A 50,000-hour lifetime generally is sufficient for signage needs. But after those 50,000 hours, the LED brightness begins to fade by a 30 percent drop off, leaving the LED illuminating at 70 percent from its original brightness, notes Smit. Because of that 70-percent figure, the spec sheet often refers to lumen maintenance as L70.
Stevenson also recommends that you closely look at the viewing angle of the LED product. For example, Stevenson explains that if you have a viewing angle of 100 degrees, your spacing approximately will measure 3" in between each LED stroke. However, a viewing angle of 155 degrees allows for 7" spacing between those LED strokes, which also improves the illumination of the sign face for a more even look. Bonilla points out that a wider viewing angle also requires fewer LED modules. Of course, fewer modules means less cost to your bottom line.
A spec sheet will help you determine the efficiency of a particular LED set. Photo courtesy of GE Lumination.
In addition to the spec sheet, Bonilla says the density guideline chart is a valuable tool. This chart tells the installer what color of LED should be used with a specified substrate.
“Sometimes, when using yellow acrylic, instead of lighting that acrylic with a soft yellow, maybe a warm white might be the best way to light it up versus using a yellow-amber color, which might make that acrylic a darker shade,” says Bonilla.
The density guideline chart particularly is handy when working with dark-colored substrates, especially blue, adds Bonilla. To create the blue color, more pigments are required, which, in turn, means more LEDs are required to effectively light the sign face.
Bonilla believes this chart is useful because they already have tested the acrylic and vinyl products from various manufacturers, which eliminates the guess work from the installer.
Remember, you also can take advantage of the complimentary layouts offered by many LED manufacturers. Your selected vendor specifies how many LED modules you need for that particular project as well as their locations within the sign.
By learning to accurately read a spec sheet, you will become an informed buyer and can more readily make educated decisions regarding your LED product.
“If you yourself can go online and take two spec sheets and look at them side by side, you should be able to determine what is the better product by whatever you deem the most important whatever it might be,” explains Fowler. “If brightness is the issue, then that is your most important spec; and you can say, is brightness so important that I’m willing to double the wattage—and so it’s just a way to be informed.”