How To Charge Self Luminous Exit Signs

Charging Your Self Luminous Exit Signs

One of the most frequently asked questions we get regards how to properly charge a self luminous exit sign. It can be a difficult concept to believe, but our SL signs do not require any charging whatsoever.

If you came to this page with the same question, rest assured you're not the only one. Electronic exit signs rely on electricity to stay lit and to charge their battery backup units. This prepares the sign in case of a sudden loss in power and ensures the sign can continue to light the exits for at least 90 minutes per OSHA standards.


See Our 10 Year Self Luminous Exit Signs

Even some non-electrical signs, like glow in the dark photoluminescent kind, still require ambient light to charge them. Self powered exit signs, however, can be placed in total darkness and still stay lit! 

Tritium Power

No Charging Required

The secret behind self-luminous fixtures is the tiny glass tubes secured to a tray inside the unit. These tubes are coated with phosphor during the manufacturing stage, then injected with a hydrogen gas called tritium. When mixed together inside the vacuum-sealed tubes, these elements will naturally glow.

Tritium is a radioactive compound that slowly degrades at a defined rate. This allows the manufacturer to gauge the exact amount of tritium needed for the model's intended life expectancy. 

Self powered exit signs are available in the following lifespans:

  • 10-year
  • 20-year

Each sign we sell has a manufacturer's label on the top or bottom, stamped with a replacement date. This is the best indicator of knowing when to replace your SL fixtures. 

Renewing Your Self Luminous Exit Sign

Once the manufacturing date is reached, your SL sign will be significantly dimmer than when you first purchased it. This gradual dimming will dip below the accepted lumens required by OSHA and UL guidelines.

See Our Self Luminous Exit Sign Disposal Services

However don't just throw away your tritium powered exit sign! Tritium, while mostly innocuous, is considered radioactive by the Nuclear Regulatory Commission. It must therefore be disposed at a licensed nuclear waste disposal company. 


In recent years, new NEC requirements have shut down a number of non-compliant disposal brokers. There are only a handful of licensed recyclers serving North America, and we have the inside connections with most of them.

Email us with your tritium disposal request or call us at 800-379-1129 for rapid service.

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