Follow the Light

In most populated areas, try going through a day without passing a cabinet sign or two — or 10, depending on the length of your commute. But an improperly illuminated cabinet sign could make the sign’s message almost invisible to its intended audience when night falls.

Since the advent of cabinet signs, internal illumination options have spanned several lighting sources, including neon, high-intensity discharge (HID) and fluorescent. Fluorescent lamps have become the most common, with HID being used somewhat frequently for large or deep cabinets.

The T12 High Output (HO) fluorescent lamp is the most popular method of lighting cabinet signs, but the future holds various possibilities, including more energy-efficient fluorescents, electrodeless lamps and light-emitting diodes (LED). T12 HO fluorescent lamps, available from various lighting manufacturers, offer approximately 12,000 hours of life, which is roughly a two-year maximum for normal sign operation.

They’re popular for internally lit, outdoor cabinet signs because they offer various colors and lengths to meet specific needs, said Roy Sierlaja, senior product specialist for GE Lighting (Cleveland). Electromagnetic ballasts have powered these lamps for years, but, recently, electronic sign ballasts have entered the market.

Their use with T12 HO rapid-start lamps is a growing trend, said David Watson, estimating and sales representative for |1659| (Birmingham, AL). Sign Builders Inc. Generally, the electronic ballast is lighter weight and offers somewhat simpler wiring, in addition to energy savings.

Electronic ballasts run at a higher frequency, which reduces the flicker associated with magnetic ballasts, according to Universal Lighting Technologies. Smaller-diameter T5 and T8 HO fluorescent lamps could soon function in outdoor cabinet signs with proper outdoor sign ballasts. Currently, those lamps are becoming more common indoors for signs or general lighting because they’re more energy efficient and can be used with various electronic ballasts when temperature isn’t an issue.

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Watson said Sign Builders has used T8 lamps for specialty applications, such as in very narrow cabinets for directional signs under Chicago’s subway system, but not in typical sign cabinets. Overall, Watson said 90% of the company’s cabinets incorporate T12 HO fluorescents with magnetic ballast (usually Universal ballasts and Sylvania lamps); 8% T12 HO with electronic ballasts; and the remaining 2% with HID metal halide for large cabinets or "high-rise" applications.

Electronic ballasts for T5s can start as low as 0F, and T8 HOs start as low as -20°F, said Eric Bobbitt, vice president of sign products for Universal Lighting Technologies. However, there aren’t outdoor, sign-specific electronic ballasts — which operate multiple lamps — for T8s or T5s, as there are for T12 HOs.

Regulations encourage a movement toward such energy-efficient lighting as T8 fluorescents — such as the 1992 Energy Policy Act (EPACT) and a ballast act that would limit magnetic ballasts, which is scheduled to take effect in 2005. Thus, T12 fluorescent lamps and their magnetic ballasts are on the path to being phased out of general lighting applications.

However, cold-temperature, special-application lighting (which includes T12 HOs for outdoor signs) is exempt from the regulations, allowing T12 HOs and their magnetic ballasts to continue in the sign industry, said Paul Walitsky, manager of environmental affairs for Philips Lighting (Somerset, NJ). But Walitsky said the sign industry should consider that other lighting is moving to T8, which could eventually make T12 lamps harder to obtain.

Jeff Barthel, cabinet department supervisor for |2288| (Watertown, SD), said the wholesale company uses many GE T12 HO Cool White fluorescent lamps with Advance electronic ballasts in cabinet signs. It also uses 175W HID metal-halide lamps and Holophane’s (Newark, OH) 400W product, which he refers to as the "Cadillac" product for lighting a large cabinet. ESCO Manufacturing

In most instances, Holophane’s Messenger series is more costly per lamp than fluorescent. It requires fewer lamps because of the high lumen output, and it can be accessed from the exterior for service because it uses elliptical fixtures typically mounted on the sides to illuminate an entire cabinet sign.

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According to Holophane, the Messenger HID lighting system will start at temperatures as low as -20°F. It offers a 20,000-hour lamp life, and light output isn’t impacted by temperature changes. Plus, the product doesn’t require additional diffusing.

In general, most HID metal halides use lamp diffusers to spread out the light. Jeff Waymouth, senior applications engineer for fluorescent lamps at |2450| (Danvers, MA), said that fluorescents offer a few more color choices than HID.

Selecting a light source

The designation of T12, T8 or T5 indicates the diameter of a fluorescent lamp. Each manufacturer offers numerous models of T12 HO, for example. Diameter is one of several criteria used for selecting the best lamp — fluorescent or otherwise — for your application requirements.

When selecting a light source, also consider the color rendering index (CRI), which describes a lamp’s ability to render accurate color on a scale of 1 to 100; and color temperature, which is a measure (in Kelvins) of how warm (red in color) or cool (blue in color) the light source appears. Color temperature impacts sign appearance and can vary among manufacturers, so it’s best to stick with one manufacturer’s lamps throughout a single sign, said Marcus Thielen, a physicist and neon-industry consultant. Additionally, the lamp — and the accompanying ballast — must be able to start at the temperature needed in the area where the sign is used. This information can be obtained by studying the data sheets provided by the lamp manufacturer, which are often found on its Website or by calling the company.

The light source used — whether you’re using fluorescent, HID or another product — depends largely on the cabinet’s size, Sylvania’s Waymouth said. Indoor cabinet signs offer greater options because start temperature is less of an issue.

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Future options

Besides the products sign companies already use in cabinet signs, several light sources hold the potential to illuminate future cabinet signs. Sylvania recently introduced the electrodeless Icetron lamp, which could be used in outdoor signs. Unlike a fluorescent, the Icetron isn’t linear and has no filaments. The Icetron offers a life of up to 100,000 hours for both the lamp and ballast, which makes it a good lighting source for large, hard-to-reach — and thus hard to service — signs. It comes in 100W with an output of 8,000 lumens, and 150W with an output of 12,000 lumens, Waymouth said.

HID ceramic metal halides, such as GE’s Constant Color, have cabinet-sign potential. Sierlaja said they offer great color, a CRI in the 90s and 20,000 hours of life.

The QL induction lighting system from Philips could be used outdoors in signs requiring long life and environments that stay above the minimum start temperature of -4°F. QL offers up to 100,000 hours of life and produces 70 lumens per watt, Walitsky said.

T8 and T5 fluorescent lamps are gaining ground indoors because of their energy savings. Future developments in the lamps and accompanying products could lead them into the outdoor arena.

Compact fluorescent lamps could also find a place in future cabinet signs. Those lamps must be rated for use inside an enclosed fixture and have a start temperature low enough to handle outdoor applications.

LEDs, which are becoming more common for use with channel letters, may find a future life lighting cabinets. Dr. Chris Bohler, director of new product development at |1054| (Valley View, OH), says that, for white LEDs to be used in cabinet signs, they would require an improved efficiency, lower cost and expanded, color-temperature range, which the company is developing.

GELcore will soon introduce a white LED system designed to replace fluorescent lighting in illuminated street signs. Bohler said these LEDs will offer lower wattage and energy savings, improved life, and the ability to withstand cold temperatures and vibrations.

Troubleshooting Fluorescent Illuminated Signs

Symptom: Repeated early lamp failure Repeated early lamp failures in a sign could mean that the problem isn’t with the lamp. To troubleshoot properly, you’ll need good lamps, good ballasts, a filament-heating voltage tester, and a volt-ohm meter or voltmeter, and a pen-type continuity tester with a pin-prick probe and alligator clip.

Step 1: Examine lamp ends for heavy, solid darkening two to four inches long, which indicates a lack of proper filament-heating voltage. Unless corrected, new lamps will continue to fail quickly. Don’t confuse a dark spot, created by collected mercury in normal operation, with this dark band.

Step 2: To make sure the cabinet is properly grounded, measure the voltage between the sign cabinet and the ballast’s white and black leads. There should be full voltage to the black primary lead and none to the white primary lead. If not properly grounded, correct the problem before continuing.

Step 3: Test the primary voltage, which should be between 110V and 130V.

Step 4: Inspect ballasts for signs of leaking filling compound or wet ballasts in the bottom of the cabinet. Replace ballasts where necessary.

Step 5: Check ballast wiring to ensure it matches the manufacturer’s specified wiring diagram. There should be no unconnected leads.

Step 6: Inspect lampholders for broken or corroded contacts, moisture or contaminants. Clean or replace as needed.

Step 7: Check for proper voltage using a filament voltage tester. With power on, the tester bulb should burn bright at each lampholder. If it doesn’t, locate the ballast leads to the lampholder. Disconnect the power. Cut and strip the leads near the ballast. Turn on the power and touch the stripped leads directly to the filament tester. If the tester doesn’t light, replace the ballast. If the tester does light, a short in the wiring from the ballast to the lampholder must be repaired.

Step 8: If the filament voltage tester burns brightly, and good lamps won’t light, shut off the power and disconnect the ballast primary leads. Check the ballast secondary leads with a continuity tester for short-to-ground condition. If the tester indicates a short, disconnect power. Cut and strip leads near each ballast, and test with a volt-ohm meter or pin-prick probe. If a short exists, establish whether the ground is in the ballast or in the sign wiring. Either replace the ballast or correct the wiring problem.

— John Tomasko
Sign industry manufacturer’s representative
Tomasko & Assoc. (Seymour, CT)

Getting More Light from Cabinet Signs

3M Commercial Graphics Div. (St. Paul, MN) offers a light-enhancement film to improve the light output in a cabinet sign. The white, diffuse, reflective film, which has a permanent, pressure-sensitive adhesive, can be applied to the sides and back of an interior, single-face sign to increase illumination. The film can be used on bare aluminum, galvanized sheet metal, painted metal and rigid plastics.

Spraylat Sign Coatings Group (Chicago) offers Star-Brite, a sprayable reflective sign coating for bare aluminum. When used with a primer for outdoor signs, the coating can increase reflectivity or eliminate "hot spots" that darken a sign.

Companies Mentioned

|2222|
Rosemont, IL
(800) 322-2086
www.advancetransformer.com Advance Transformer

GE Lighting
Cleveland
(800) 435-4448
www.gelighting.com

Holophane
Newark, OH
(740) 345-9631
www.holophane.com

Osram Sylvania
Danvers, MA
(978) 777-1900
www.sylvania.com

Philips Lighting
Somerset, NJ
(800) 555-0050
www.lighting.philips.com

Universal Lighting
Technologies
Nashville, TN
(800) 225-5278
www.universalballast.com Osram Sylvania