Firefighters use protective gloves (fig. 1a) to defend themselves from hazards like burning or cutting.
Unfortunately while using them they are not sensitive enough for perception of heat and danger. Before
entering a room with unknown fire danger they have to undress their gloves to feel the temperature of the
door. This cause additional danger and necessary rescue time is lost. On the other hand they have to enter
a burning room and want to be sure if their protective defend them from heat. If the inner temperature
reaches a critical level very fast a thermal breakdown can occur where the heat protection fails, so a
warning procedure is needed to prepare the firefighter for escape.