x » Emergency LightsSpectrum Enterprises

 

Emergency Lights

Written by Ed Clark, Spectrum Enterprises

  

© Dinna79 | Stock Free Images & Dreamstime Stock Photos

If I had a nickel for every time maintenance or management staff gave me an exasperated look and said “I swear we just checked those emergency lights yesterday and they were fine”, I’d have a boatload of nickels. The frustration is completely understandable. Why is it one day they work fine and the next day they don’t?

A few people have commented that they felt Spectrum’s method of testing emergency lights actually contributed to a high rate of failure and was not a reasonable method of testing. They felt prolonged use of the batteries somehow prevents them from being able to regain a full re-charge later. This may in fact be true. All types of rechargeable batteries have a limited number of discharge-charge cycles available to them. Batteries generally come in four basic flavors. Nickel Cadmium, Lead Acid. Nickel Metal Hydride and Lithium Ion. Old fashioned Nickle Cadmium and Lead Acid batteries are what you usually find. Both are old technology and have the advantage of being inexpensive to manufacture.

A lot of exit signs use tiny little battery packs that are not much more than a couple of AA batteries taped together and incorporated into the lighting circuit. These are usually Nickel Cadmium batteries. You see Lead Acid batteries in the older style emergency light fixtures (also in your car) They are big, heavy and are usually good for three years or more under normal conditions. After that, their ability to sustain illumination for 90 minutes becomes suspect. Nickel Metal Hydride is more expensive than Nickel Cadmium but offer many discharge cycles and also have the ability to recharge almost completely even if they were only discharged a little bit. Unfortunately, I don’t think they are offered in emergency lighting systems, neither are Lithium Ion batteries.

It’s possible very inexpensive exit signs don’t even have a recharging circuit. You might want to ask your supplier if that is the case. It would certainly explain why a prolonged test of the emergency lighting system would result in a high rate of failure, especially if your staff just tested them a day or two before.

The best way to reduce the number of failures is to tag each light and exit sign with the date the battery was last replaced. Rechargeable batteries should probably be replaced every three years or more often if you have numerous power failures, even short disruptions in power create a charging cycle and every battery can only go through just so many of those before if gives up and dies. If you find you have emergency exit signs that don’t recharge the batteries you probably should budget for battery replacement every year, just like you do for smoke detectors and Carbon Monoxide detectors in apartments. You do replace those batteries every year right?

Please note: Spectrum is hiring!  See this link for details about the position and application instructions.

Tags:


Subscribe to Our Blog

 

 Subscribe in a reader