What is a Tritium Exit Sign?

A tritium exit sign is one of two types of UL924 compliant non-electrical exit signs that may be used in lieu of standard hard-wired electrical exit signs. The exit sign will have viewing distance ratings, typically 100ft. The sign is powered by tritium filled coated borosilicate tubes that glow green in the dark. The tubes are typically oriented in a drop-resistant tray that spells out the letters E-X-I-T with two tubes comprising the arrows. If the sign is intended to support a customizable legend/"wording" such as handicap access route, then the tubes may be oriented differently, typically vertical and offset by several inches. The tubes are sealed and fastened to the tray via adhesive/glue. Above the tray is a lens that refracts light so as to increase the illuminated area of the face. The legend may be painted or powder-coated aluminum or lexan or similar. The colors of the faces are typically green, red, black, or white, although custom colors or finishes are possible, such as bronze. The sign is framed typically with aluminum or thermoplastic. The sign is installed using screws which are supplied and is capable of being mounted top, sign, or back. The ease of installation is the key benefit to these signs.

There are some considerations for tritium exit signs. The signs do expire as they rely on the emitting of a nuclear beta particle to excite the coated glass tube. The life spans are rated between 8-20 years, although typically now UL 924 rated versions are sold as 10 or 20 years. The signs are licensed and some states require a licensing fee. Upon purchase there is a registration that occurs which includes the building where the signs will be installed and a contact person. The signs must be recycled at the end of their usage which costs approximately $100-$250 per sign depending on shipping costs and the channel through which are recycled. Often with the purchase of a replacement sign the recycling costs can be reduced. If the sign is damaged, precautions and care must be taken. Ask for the MSDS for the sign, although the original box will include these with installation instructions.

Tritium exit signs are a great choice for reasons other than being non-electrical, for example, movie theaters use them due to the signs being bright enough to been seen but not too bright to interfere with the screen. Art galleries and museums use them because the signs are able to be repositioned as the room layouts change. They are used often poolside because they are able to mounted to gates. They are used in areas of flammable gases or vapors because they cannot be a source of ignition. They are used in haunted houses because they are light enough to able to be installed on many surfaces.