Photoluminescent Exit Signs
Permalight Exit signs are non-radioactive and non-toxic, maintenance free, non-electrical. They have no light bulbs to burn out and are easy to install with just four screws, according to American Permalight. The firm says it has gotten the signs tested by UL to comply with UL924 as official emergency lighting. The exit signs require 54 lux of activation by fluorescent lighting and shall be installed every 50 feet.