How to Identify a Tritium Exit Sign
Many exit signs contain tritium. Tritium is a naturally-occurring radioactive isotope of hydrogen that is often used to light up a sign without batteries or electricity. Tritium exit signs will glow without electricity or batteries for more than 10 years. This is beneficial in areas where it is difficult to install electric signs (like above doors) and in emergency situations when power is lost.
If your exit signs contain tritum gas it is important that you handle it properly and dispose of it per US NRC regulations when it expires.
There are a couple ways to know whether an EXIT sign contains tritium. When the lights are off, tritium will make the word EXIT glow green or red. The sign should also have a permanent warning label that mentions tritium, 3H or H-3; displays the three-bladed radiation warning symbol; and states “Caution-Radioactive Materials.” If all four letters in EXIT are fully lit, the sign is working properly. If not, the sign may be damaged or have reached the end of its working life.
The exit sign below shows some of the key characteristics of tritium containing exit signs:
Handling Tritium Exit Signs
- If possible, turn the lights in the room off before removing a tritium sign. If a tritium-filled tube is broken or damaged that letter on the sign will be dark.
- Wear water-resistant gloves as a precautionary measure. If the tritium tubes break, you can avoid absorption of the tritium through your hands.
- Handle intact signs carefully, especially when installing or removing the sign. Most signs are damaged when being installed or removed.
- If you damage a sign, do not attempt to handle it. Immediately inform your safety officer or call your state’s radiation control program.