Published In February 2001
Fires take the lives of thousands of people each year. In 1998 and 1999 alone, 4,035 and 3,570 civilian fire deaths occurred in the United States. The most deadly fires often occur in industrial settings. In 1999, 17,500 fires on industrial properties, 9.4 percent more than in 1998, resulted in 120 civilian deaths, and $1.4 billion in property damage. In 1999, industry was plagued with deadly industrial fires. For example, in January, a fire at a bolt-making plant in Mariesville, Fla., killed two workers. Then in February, a fire at the Rouge Steel Company in Dearborn, Mich., killed several employees; a fire at the Concept Sciences plant in Allentown, Pa., killed five; and a generating plant in Kansas City, Mo., left one dead and 21 injured. Tragically, the list goes on and on. This rash of deadly fires has stimulated a revival of national fire safety and prevention awareness. Over the past decade, emergency lighting technology is one area of fire safety that has significantly advanced. Progression of emergency lighting technology Ten years ago most exit signs used incandescent lamps. These lamps only lasted about 5,000 hours and had poor energy efficiency. To operate properly, these lamps required changing twice a year. Neglecting this frequent maintenance could yield devastating results. Incandescent emergency lighting’s drawbacks led to fluorescent lamp sources becoming an alternative. Although it provided longer lamp life, lasting about 10,000 hours, and only requiring annual maintenance, fluorescent lighting’s operating cost was high. Today’s exit signs use light-emitting diodes (LEDs) the most economical and energy-efficient lamp source available, lasting more than 10 years. Benefits of LED emergency lighting systems Introduced in 1969, LEDs are compound semiconductor devices that convert electricity to light when biased in the forward direction. Today, advanced high-brightness LEDs are being installed in a variety of lighting applications. LEDs’ benefits include their compact size, low wattage, low heat, long life, uniform brightness, and compatibility with integrated circuits. LEDs emit red or green light, depending upon their chemical makeup. Red has traditionally been the preferred wavelength. Since red light scatters 6.5 times less than blue, it penetrates better through a smoke-filled environment. Green exit signs have been favored in recent years because sensitivity of the human eye increases with shorter wavelengths. Die-cast aluminum exit signs with LED lamps are dependable, rugged, and designed for aesthetic appeal. These essential features make the exits ideal for various applications, such as high-end architectural, educational institutions, and hazardous locations where emergency lighting is necessary. These types of exit signs with the LED lamps generate no heat and are suitable for wet locations, which is important, since fire sprinkler systems are often activated. Choosing an LED emergency lighting source Not all LED lamps perform the same. Qualifications to consider when choosing an emergency light source include the following: * Al In Gap versus Al Ga As. The first qualification is choosing the best form of LED light. Two types are most widely used in today’s exit sign market: the Aluminum Indium Gallium Phosphide (Al In Gap) and the Allumium Gallium Arsinide (Al Ga As). The Al In Gap LED lamp, introduced in the ’90s, has a the wavelength of 630 (nm) and provides an extremely stable, long-term light output. At 20ma, minimum intensity is 1,000 (mcd), and the typical intensity is 4,000 (mcd). The Al Ga As technology has very high luminous efficiency, capable of producing high light output. Introduced in the ’80s, its wavelength is 644 (nm) but has a shorter life span than the Al In Gap LED technology. At 20ma, minimum intensity is 290 (mcd), and the typical intensity is 750 (mcd). * Self-diagnostic. Unfortunately, research has shown that many emergency lighting systems are neither maintained properly nor inspected. During most emergencies, the current power supply fails and a battery backup is required to power the emergency systems. Without regular maintenance, these batteries may not function after a fire. Self-diagnostic emergency lighting units are the easiest way to combat this neglect. This type of circuitry monitors the voltage and the function on the individual units typically for one minute every 30 days and for 30 minutes every six months. Some products have an indicator light to inform you of when to replace any defective part. * Laser light. Often during a fire, smoke obscures the chevron directional indicator on an exit sign from a distance. Therefore, emergency laser light technology was developed in 1998 to work in conjunction with the exit sign. With this new technology, some systems use an approved class 3a laser option to direct occupants to exits in dense smoke. Such a lighting system activates a red laser beam when in the emergency mode and provides directional light up to 40 feet, depending on the intensity of the smoke. The laser beam can be pointed down the path of egress, which will direct you without hesitation to safety before you’re close enough to read the exit sign. Soon laser lighting will be incorporated in to more emergency products. Also, strobe features will be designed in with the exit signs for the hearing impaired, since they are unable to hear fire alarms. * Tamper-resistance and easy installation. Tamper-resistance and ease of installation are important to building owners. Most emergency lighting systems use a vandal-resistant lens over the exit face that is kept in place with tamper-proof screws. This is especially important in college dorms, where pranks are frequent. The new laser light emergency systems also offer ease of installation. First, laser units are easily mounted, then installers can rotate the laser beam eye up to 180 degrees to point to the exits. The future of emergency lighting Most, if not all, local code jurisdictions have incorporated some form of standards relative to exit signs and emergency lighting. They may incorporate National Codes, such as National Fire Protection Association (NFPA), or National Building Codes, such as the Uniform Building Code. Alternately, they could require products tested by a third-party safety certification company, such as Underwriters Laboratories Inc.,(UL). Exit signs listed as UL 924 comply with NFPA 101. Some standards have become more restrictive in the last couple of years, but emergency lighting standards may become even more so. Driven by insurance companies offering lower premiums to buildings with up-to-code standards, building owners may update their emergency lighting systems to the more reliable LED lamp sources. GREGORY is mcPhilben’s emergency lighting product manager. For more information, call (800) 234-1890 x 6688 or visit www.dcolighting.com.