The tritium decays at a snails pace, emitting electrons that cause the phosphor to glow. These glass tubes are internally coated with zinc sulfide phosphor and then filled with tritium gas. Inside the aluminum and polycarbonate housing, tiny glass tubes are affixed to the backplate of the sign they are very difficult to dislodge. Depending on how your SL sign is built, it will last between 10 and 20 years! How Self Luminous Signs Work Tritium does not require power from an electrical source nor do they need ambient lighting to be on at all times like glow in the dark exit signs. A special hydrogen gas called tritium, which is a naturally glowing green compound, is the magic that makes these signs work so well. It isn't an optical illusion or a magic trick that keeps these self illuminating signs lit.
The third type requires no electricity and can be placed in total darkness - the self luminous exit sign! Check Out Our Inexpensive Self Luminous Exit Signs Others are glow in the dark and require the availability of artificial lighting to charge their photoluminescent surfaces. Most exit signs operate on electricity, used to power their LED or incandescent light strips inside.
