The inclusion of tritium in exit signs makes for a nuclear exit sign, because tritium is considered nuclear energy. The following will detail everything you need to know about the use of tritium in exit signs. Some models of glow in the dark exit signs, especially older exit sign models, contain a radioactive gas called tritium. Tritium signs do not require a direct current of electricity or batteries to operate, and can be used in areas that are difficult to install exit signs that need to be connected to a power source, such as above doors. Tritium is a radioactive isotope of hydrogen. When put into exit signs, tritium gas is contained in sealed glass tubes that are lined with a light emitting compound. The tritium will then emit radiation that causes the inner lining to glow. Tritium gas is odorless, colorless, and tasteless, and has been measured as being lighter than air.
To know whether an exit sign contains tritium, when in a dark area, the tritium will make the exit sign glow green or red. A tritium exit sign should also have a permanent warning label indicating the use of tritium. If any of the letters in an exit sign are no longer fully lit, the sign might have become damaged or has reached the end of its life cycle. Many buildings and industrial facilities throughout the United States still use tritium, or nuclear, exit signs, despite the creation of more resourceful, safer, and more dependable exit sign technology.
Manufacturers and distributors of tritium exit signs must apply for and receive a radioactive materials license in order to use the technology to ensure optimal safety by mandating expert use of the radioactive materials. It is the concern of radioactive components that makes tritium subject to certain regulatory requirements, which includes a mandatory requirement for proper disposal because a damaged tritium exit sign could contaminate the disposal area and require expensive cleanup. Federal regulations concerning tritium exit signs holds a general licensee that uses the nuclear technology to the following:
- Under no circumstances may a person remove the labeling or radioactive symbol on the exit sign, nor abandon the sign.
- The entity must always properly dispose of an unusable tritium exit sign.
- The entity must report to the Nuclear Regulatory Commission (NRC), or to the appropriate Agreement State, any lost, stolen, or broken tritium exit signs.
- Must inform the NRC or the Agreement State of any changes to the name or address of the general licensee, or the person and / or business in charge of complying with the regulations.
- Must never relinquish or sell the tritium exit sign unless it is to remain in use at its original location.
Tritium exit signs should never be disposed of in the same manner as normal trash. To dispose of a tritium exit sign properly, a general licensee must transfer the sign to a specific licensee – such as a manufacturer, distributor, licensed radioactive waste broker, or a licensed radioactive waste disposal facility. In addition, the general licensee must file a report to the NRC or Agreement State within thirty days of the disposal of the tritium exit sign.