Exit sign

I want to introduct something about EAR0019 Earring.

We can provide kinds of jewelry for your selection Nice and unique design any size and most of colours are available Accept OEM Packing:Individual polybag ,12pcs per master according to customers requirement EAR0019 Earring mo




A well-designed fire exit sign is easily seen, even if visibility is poor. This type of sign, with the word "EXIT" in red or green, is the most commonly seen in the United States. Note the emergency lighting immediately above the sign



Emergency exit in the Stockholm Metro

An exit sign is a device in a public facility (such as a building, airplane or boat) that displays where the emergency exit is.

Most exit signs around the world are in pictogram form, with or without text supplement. There has been a shift towards the adoption of such exit signs in the recent decade. A small minority of nations adhered to the exit signs that show the word "EXIT" (or similar in another language). Its purpose is guiding people to the closest exit in case of fire or other emergency. The English word "exit" comes directly from the Latin word meaning "to go out." Most fire codes require exit signs to be permanently lit.

Since visibility may be reduced in a fire, due to smoke or failure of electric lighting, the sign is often permanently illuminated, usually by one of:

Radioluminescence, ('traser'), self-luminous, where a phosphor coating inside a glass tube glows due to the beta decay of radioactive tritium in the tube. Radioluminescence exit signs are prohibited in Department of Defense installations by the Unified Facility Criteria (UFC) 3-600-01 (http://www.wbdg.org/ccb/DOD/UFC/ufc_3_600_01.pdf)

Phosphorescence ('glow in the dark'), Photoluminescent, where light is absorbed from the surroundings and slowly re-emitted.

Electric light, with a local rechargeable power source.

Electric light, with the building's emergency lighting circuits providing back-up power from a UPS and/or a generator in case normal power is lost.

Contents

1 History

2 Modern installations

3 Battery backup

4 Self luminous exit signs

5 Red or green

6 External links


//


History



Earlier exit signs such as this one were powered by incandescent bulbs and appeared relatively dim.

Early exit signs were generally either made of metal and lit by a nearby incandescent light bulb or were a glass cover that fit directly over a single-bulb light fixture. The inherent flaws with these designs were that, in a fire, the power to the light often failed. In addition, the fixtures were small and dim, making them hard to spot in a fire where smoke often reduced visibility. Better signs were soon developed that more resembled today's modern exit sign, with an incandescent bulb inside a rectangular-shaped box that backlit the word "EXIT" on both sides. Being larger than its predecessors, this version of the exit sign solved some of the visibility problem. The sign was only useful as long as main power remained on.



Emergency exit sign used in Japan and South Korea, also sometimes used in the UK (BS 5499), New York City (LL26) and Norway

As battery-backup systems became smaller and more efficient, some exit signs began to use a dual-power system. Under normal conditions, the exit sign was lit by main power and the battery was in a charge state. In the event of a power outage, the battery would supply power to light the sign. It continued to discharge until main power returned to the unit or the battery was no longer able to provide sufficient power to light the sign. Early battery-backup systems were big, heavy, and costly. Modern systems are lightweight, can be installed virtually anywhere, and are integrated into the fixture, rather than requiring a separate box. As batteries improved, so did the amount of time that a fixture could remain lit on batteries.



Emergency fire exit sign as used in Hong Kong.

While exit signs were more visible due to large letters, even a 60-watt bulb shown through a plastic or glass cover (see image), appeared somewhat dim. With the development of fluorescent lamp and light-emitting diode technology, exit signs could be made even brighter to show up in the limited visibility of a fire situation, and/or use less electricity. LED signs work by combining a large number of bright light-emitting diodes to illuminate the sign from inside. Fluorescent bulbs work in the same way as incandescent bulbs, backlighting both sides of an exit fixture from the inside. Because an exit sign is constantly lit, fluorescent bulbs need to be changed more often than LEDs. As a rule, LEDs have a very long life, and may last for 10 years or more of continuous use, although the brightness may diminish. Incandescent bulbs are still in use, because they are cheap and common, even though they use more electricity and require frequent replacement. In recent years, radioluminescent and phosphorescent signs require no electricity have also been developed. Radioluminescence uses the radioactive decay of tritium to light the sign, while phosphorescence uses light-emitting phosphors to...(and so on)
To get More information , you can visit some products about
kid tricycle,
rubber air hose,
.
The EAR0019 Earring products should be show more here!