The Evolution of Exit Signs (and Why the Latest is a Bad Idea)

Exit signs have become vastly more efficient in recent years. This article examines exit sign options and explains why the latest, photoluminescent signs, are not effective in many situations. Until recently, most exit signs were illuminated by incandescent light bulbs. Because of their higher energy efficiency, compact fluorescent lamps (CFLs) have replaced many incandescent bulbs and signs, but CFLs contain mercury and must be disposed of properly or recycled. Radioluminescent (tritium) signs use tubes of radioactive gas to produce a green...