Eco-Friendly Exit Signs Don't Require Electricity to Glow
by Jaymi Heimbuch, San Francisco, California on 12. 2.08
Image via Jessup Manufacturing
A bit of oddball news – exit signs are saying goodbye to excess energy consumption. A company called Jessup Manufacturing has come up with an eco alternative to plug-in exit signs. Instead of electricity, they use ambient light to charge up - but are even better than solar powered signs.
Much the same as signage produced by ecoglo, The Eco Exit PM 100 is a non-radioactive photoluminescent safety sign that absorbs and stores ambient light, and in dark situations, the sign is immediately visible up to 100 feet. It lasts a whopping 25 years with virtually zero maintenance, making it even more low-energy. Plus, it gets builders points towards LEED certification.
A cost analysis by the company (so take it relatively lightly) shows that a building that replaces 100 incandescent exit signs with 100 Eco Exit signs can save about $3,450 annually in costs. There is even a savings of about $712 annually over LED signs.
But it isn’t without drawbacks. Rather than encouraging recycling, the company claims it has “easy landfill disposal.” Not so cool. While replacing those bulky energy sucking electric-powered exit signs is a huge plus, it’d be even better if it featured “easy recyclability.” At least make them able to be turned into coasters or something.
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Passive Emergency Lighting
Solar-Powered Traffic Signs
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I sure hope these aren't like the cheezy toys and other glow in the dark accessories that charge with ambient light. Anything that I've ever used that you have to hold up to a light or just leave in your room and glows when you turn out the light only lasts a pathetically short period of time and emits very little usable light.
I worked for a company called creativesignage.com and basically these thing really work.
They do charge during the day with ambiant light etc.. But last for hours in total darkness.
After 9/11, companies with big building had to have these things installed in case of a similar emergency. I think if its above 25 floors they will require them.
it was fun seeing these signs at night. i think there is a life expectancy for them, but they saved alot of money in the long run.
Many exit signs are already self-powered using beta particles from tritium to fluoresce.
Environmental Building News (where I work) reported on photoluminescent exit signs in 2006. With tens of millions deployed in North America that use up to 350 kWh annually (as much as a nicely efficient refrigerator), it's a big deal. EPA estimates are that exit signs in commercial buildings use 30 - 35 billion kWh per year... the output of about a dozen 1000-MW coal-fired power plants.
CFL exit signs use far less power and require far fewer lamp change-outs than incandescent. LED exit signs use only a couple watts. Electroluminescent signs use even less power than LEDs. Electricity-free radioluminescent exist signs - the tritium ones noted in another comment - have been around since the '20s, generally have 5 - 20 year lifespans, and disposal is regulated in the U.S. by the Nuclear Regulatory Commission (though it's probably a given that most of them end up in landfills anyway).
And PL exit signs, as noted in the post, also need no power at all... sort of. The manufacturers' recommendations for some of these signs call for a minimum continuous face exposure of of five footcandles (54 lux) of ambient light. But with low-energy lighting designs for interior spaces, the ambient light at the ceiling - where these signs are installed - the face of the exit sign would get on the order of 1 footcandle. Accommodating the charge requirements for PL exit signs in this kind of situation creates a significant energy penalty.
It should be noted that the NYC law requiring PL exit markings (in all Class E commercial high-rise buildings over 75 feet in height) isn't actually about exit signs - though maybe the other commenter is talking about a different law that I'm not aware of. The post-9/11 NYC Building Code Reference Standard RS 6-1 and 6-1A didn't change requirements for exit signs above doors, but did create specific requirements for PL exit path markings on stairs, handrails, exit doors, and other places. That law also requires at least 2 footcandles of light on the floors of corridors to maintain the markings' charge, and nixes motion sensors that interrupt continuous light levels of at least that much.
What sort of exit signage and marking is appropriate is part of an overall lighting and energy-use design that meets local code requirements and national laws. PL can be appropriate. It isn't always. It can get especially tricky when the concept is removed from general theory and inserted into design reality.
The Evolution of Exit Signs (and Why the Latest is a Bad Idea)
http://www.buildinggreen.com/auth/article.cfm/2006/10/27/The-Evolution-of-Exit-Signs-and-Why-the-Latest-is-a-Bad-Idea/
Support for Photoluminescent Exit Signs
http://www.buildinggreen.com/auth/article.cfm/2007/1/2/Support-for-Photoluminescent-Exit-Signs/?
More:
http://www.buildinggreen.com/search/index.cfm?q=exit+signs