What is Tritium
Tritium gas (chemical symbol 3H) is an isotope of hydrogen gas, and is colourless, odourless, and lighter than air. Most physical characteristics are the same as hydrogen, but the atoms in tritium are slightly different, causing them to emit low energy in the form of ionising radiation, or electrons.Tritium is considered “user friendly” because it has the lowest energy rating of any radioisotope. The energy of tritium electrons is much less than those generated in electrical lamps, which is why you cannot see tritium tubes glow except in dim light or darkness.
BetaluxTM signs are lit by means of tubes of borosilicate glass ﬁlled with tritium gas. On the inside the tubes are coated with a ﬂuorescent powder, which continuously emits light due to the ionising radiation of the tritium gas, for up to 131,000 hours. The entire tube is comparable to a ﬂuorescent lamp, for which the current going through the lamp is replaced by tritium gas, therefore, no electrical connection is needed. This form of escape route marking has already been applied in aeroplanes, where reliability comes ﬁrst, for over 50 years.