An exit sign in a public building show people which way to take to get out of it. Its and most important purpose is to tell people about the emergency doors in case of any accident such as fire or such others. Many buildings have codes with these signs such as safety, and fire and health or building authorities require these signs to lit all the time.
These signs are being designed with a clear knowledge for people of safe ways so that there will not be any misunderstanding. In the beginning there was just a board, word exit written on it in English or in other regional languages so that people can understand easily, but now they are increasingly in pictogram form with or without text, and people do understand it very clearly.
Early design was made of metal or lit by a light bulb or it was made on a glass “exit” written on it in red. There were many flaws in these designs such as they were unable to locate in case of smoke, in case of fire the power of light get failed, the brightness of the sign didn’t make it easier for people to see it. To solve that problem red tinted globes got to be used instead of other designs.
These designs kept getting better and better with the time, and the designs introduced which were more like today’s signs. Then a rectangular box used with a bulb in it and the exit written on both sides of the box. Because of its sign, it was more visible to people in case of smoke and fire. But it was only useful till the time electric power remain. Then the battery-backup system got launched. Early system was heavy and costly but the modern system is light in weight and can be installed anywhere needed.
After sometimes LED lights were introduced. These lights were made with the combination of bright light-emitting diodes to light up the sign. Fluorescent lamps and incandescent bulbs work in same manner. These signs work 24 hours a day which is more than any other light so the fluorescent bulbs need to be replaced more frequently than LED lights, on the other hand LED lights are more long lasting but their light get dim with time, and they also consume less electricity than incandescent. These bulbs are cheaper than others so they are still being used, it need more electric power but last longer and do not need continuous replacement.
These signs are very important in building where public visits are very frequent for the safety of people.
