With tighter regulations and a greater need for emergency lighting in commercial buildings, product developers are continually focusing on ways to make exit and emergency lights more energy efficient and easier to self-diagnose.
Local standards have become more restrictive for all lighting in the last couple of years, but emergency lighting standards have become even more so. Insurance companies that offer lower premiums on buildings kept up to code lead that trend. With all this in mind, many building owners opt to update their emergency lighting systems to the more reliable LED lamp sources. Typically, emergency power systems are installed where lighting is required for safe exiting and panic control.
In the last decade, incandescent lamps, which had poor energy efficiency and lasted only 5,000 hours, have been almost completely replaced—first by fluorescents then LEDs. It was a safety hazard and an economic issue. Incandescents, which could require changing twice a year, were often inoperable if building owners didn’t keep up with diagnostic testing.
On the other hand LEDs can last 10 or more years. Rapidly growing in popularity, LED exit signs offer a series of improvements over the older systems: energy-saving low wattage, long life and improved visibility. LEDs got off to a slow start mostly because their original first costs were much higher than other nonemergency lighting. That initial cost has dropped thanks to improved optical designs that allow higher efficiency. Red LEDs offer the most energy efficiency with the highest light output per watt input.
Self-diagnosis is one major concern for building owners. During most emergencies, the current power supply fails and a battery backup is required to power the emergency systems. Without properly scheduled maintenance, the batteries may not function in an emergency. Most codes require regular diagnostic testing, including an annual test for a 90-minute duration. Self-diagnostic emergency lighting units offer an easy way to address this. The self-diagnostic circuitry monitors the voltage and the function on the individual units, usually for one minute every 30 days and for 30 minutes every six months. Another option is a product with an indicator that illuminates when the system malfunctions.
Dennis Gregory, emergency lighting product manager with McPhilben Emergency and Exit Lighting, says his company is working on new products that offer self-diagnostic circuitry. McPhilben’s product verifies battery voltage and lamps every 10 seconds. Another option is a hand-held laser pin that can be pointed at the sensor from 12 feet and indicate whether the lights are functional.
There are no specific schedules listed by NEC for diagnostic testing of emergency lights. The only requirement is that testing be performed regularly at a frequency acceptable to the local authority having jurisdiction, which usually accepts testing recommendations listed by light manufacturers.
However, NEC Paragraph 700-4(e) dictates that testing of emergency lighting and power systems should be done under the determined maximum load. The requirements for load testing emergency power systems are much more stringent than standby power systems. In accordance with NEC Paragraph 701-5(e), standby systems only have to be tested under load—not for the maximum load anticipated.
Since both emergency and legally required standby systems are usually combined, it’s advisable to test under the more stringent requirements.
Full-load testing shows if an emergency or standby system will function properly when needed. This requires installing a load bank that is equal to the anticipated maximum load or, better yet, to the power source rating. To protect sensitive electronic equipment from damage and downtime, a load bank can be installed that is equal to the expected maximum load.
However, even if a load bank is provided, the emergency or legally mandated standby power system should be tested using the actual load to ensure whole-system operation.
There are also specific instructions for testing emergency and standby lighting systems. NFPA 110, Section 6.4 states that these systems need to be tested monthly for at least 30 minutes under specified loads. NFPA 110 Section 6.4 is the best bet to follow when developing a testing and maintenance program for either emergency or standby generators.
In some businesses specific emergency lighting systems are essential. Control emergency lights are needed in buildings such as theaters where dimmed lighting can be automatically increased to NFPA Life Safety Code specifications by an activated fire alarm system. This Code also requires that any building with reduced lights must have a system that automatically increases lighting to a level that will activate the fire alarm. Usually a fire alarm relay on a circuit monitored for integrity is required to be installed no more than three feet from the lighting control. EC
SWEDBERG is a freelance writer based in Somerset, N.J. She can be reached at firstname.lastname@example.org.