News and Information for Public Egress, Building Safety and Government Compliance
An emergency light is a battery-backed lighting device that comes on automatically when a building experiences a power outage. Emergency lights are standard in new commercial and high occupancy residential buildings, such as college dormitories. Most building codes require that they be installed in older buildings as well.
By the nature of the device, an emergency light is designed to come on when the power goes out. Every model, therefore, requires some sort of a battery or generator system that could provide electricity to the lights during a blackout. The earliest models were incandescent light bulbs which could dimly light an area during a blackout and perhaps provide enough light to solve the power problem or evacuate the building. It was quickly realized, however, that a more focused, brighter, and longer-lasting light was needed. The modern emergency floodlight provides a high-lumen, wide-coverage light that can illuminate an area quite well. Some lights are halogen, and provide a light source and intensity similar to that of an automobile headlight.
Early battery backup systems were huge, dwarfing the size of the lights for which they provided power. The systems normally used lead acid batteries to store a full 120-volt charge. For comparison, an automobile uses a single lead acid battery as part of the ignition system. Simple transistor or relay technology was used to switch on the lights and battery supply in the event of a power failure. The size of these units, as well as the weight and cost, made them relatively rare installations. As technology developed further, the voltage requirements for lights dropped, and subsequently the size of the batteries was reduced as well. Modern lights are only as large as the bulbs themselves – the battery fits quite well in the base of the fixture.
Modern emergency lighting is installed in virtually every commercial and high occupancy residential building. The lights consist of one or more incandescent bulbs or one or more clusters of high-intensity light-emitting diodes (LED). The emergency lighting heads are usually either PAR 36 sealed beams or wedge base lamps. All units have some sort of a reflector to focus and intensify the light they produce. This can either be in the form of a plastic cover over the fixture, or a reflector placed behind the light source. Most individual light sources can be rotated and aimed for where light is needed most in an emergency, such as toward fire exits. Modern fixtures usually have a test button of some sort which temporarily overrides the unit and causes it to switch on the lights and operate from battery power even if the main power is still on. Modern systems are operated with relatively low voltage, usually from 6-12 volts. This both reduces the size of the batteries required and reduces the load on the circuit to which the emergency light is wired. Modern fixtures include a small transformer in the base of the fixture which steps-down the voltage from main current to the low voltage required by the lights. Batteries are commonly made of lead-calcium, and can last for 10 years or more on continuous charge. U.S. fire safety codes require a minimum of 90 minutes on battery power during a power outage along the path of egress.
As a method of signaling a power outage, some models of emergency lights must be shut off manually after they have been activated. This is true even if the main building power comes back on. The system will stay lit until the reset button on the side of the unit is pressed.
Modern Emergency Light Design
Emergency lighting is often referred to as egress lighting. Emergency lights are used in commercial buildings as a safety precaution to power outages, so that people will be able to find their way out of a building. Exit signs are often used in conjunction with emergency lighting.
New York City requires emergency lights to carry a Calendar Number signifying approval for local installation, Chicago requires emergency lighting to have a metal face plate, and Los Angeles requires additional exit signs be installed within 18 inches (460 mm) of the floor around doors to mark exits during a fire, as smoke rises and tends to block out higher installed units.
As there are strict requirements to provide an average of one footcandle of light along the path of egress, emergency lighting should be selected carefully to ensure codes are met.
In recent years, emergency lighting has started to move away from the traditional two-head unit – with manufacturers stretching the concept of emergency lighting to accommodate and integrate emergency lighting into the architecture.
An emergency lighting installation may be either a central standby source such as a bank of lead acid batteries and control gear/chargers supplying slave fittings throughout the building, or may be constructed using self-contained emergency fittings which incorporate the lamp, battery, charger and control equipment.
Self-contained emergency lighting fittings may operate in “Maintained” mode (illuminate all the time) or “Non-Maintained” mode (illuminated only when the normal supply fails).
Codes of practice for emergency lighting generally mandate that wiring from the central power source to emergency luminaires is kept segregated from other wiring, and constructed in fire resistant cabling and wiring systems.
Codes of practice lay down minimum illumination levels in escape routes and open areas. Codes of practice also lay down requirements governing siting of emergency lighting fittings, for example the UK code of practice, BS5266 specifies that a fitting must be within 2 metres (6 ft 7 in) horizontal distance of a fire alarm call point or location for fire fighting appliances.
The most recent codes of practice require the designer to allow for both failure of the supply to the building and the failure of an individual lighting circuit. BS5266 requires that when Non Maintained fittings are used, they must be supplied from the same final circuit as the main lighting circuit in the area.
IEC 60364-5-56 Ed. 2.0: Low-voltage electrical installations – Part 5-56:  Selection and erection of electrical equipment – Safety services
ISO 30061:2007 (CIE S 020/E:2007): Emergency lighting (specifies the luminous requirements for emergency lighting systems)
In case of power outage or an emergency, batteries play a significant role in minimizing risk. Having efficient emergency lighting isn’t enough if your batteries don’t function properly. That’s why you should consider all the factors before choosing light batteries for your exit signs or emergency lights.
The Purpose of Emergency Light Batteries:
When the electricity is off, batteries function as a light activator. As a rule, they can provide the light for 90 minutes or more. Please note that the batteries used for emergency lights should be more powerful than those used for exit signs.
Features That Determine Effective Light Batteries:
– Need to have enough power to illuminate the room for 90 minutes.
– 24 hours should be enough for their full charge.
– Need to have the required voltage capacity to power emergency lights or exit signs.
– They should be easily replaced and installed.
Types of Emergency Light Batteries:
– Nickel cadmium – they are ideal for small exit signs, emergency lights and electronic devices.
– Lead acid – these batteries are suitable for small and medium emergency lights and exit signs.
– Lead calcium – these lead acid batteries are usually used in cold environments. They need lower maintenance cost and are more durable in comparison with other types.
The Efficiency of Rechargeable Batteries
Even though rechargeable batteries are quite expensive when compared with traditional ones, they are more durable and can be easily recharged. They are perfectly suitable for emergency lights, exit signs or other electronic devices.
You should be prepared for possible emergency situations that may happen at any time and lead to unpleasant consequences. Aimed at reducing the harm caused by the emergency, lighted LED exit sign is a great precaution and tool to mitigate the risk.
The main function of LED exit signs is to help people find the nearest exit. Power outages can often be triggered by the fire, earthquake, etc. When the air is filled with smoke, it is even harder to find the way. Exit signs that are powered with the rechargeable batteries will be the most effective solution to saving people from the damaging power of an emergency situation.
The use of LED technology provides great illumination and visibility in smoke. LED exit signs are more energy efficient than incandescent signs. They may operate for up to 10 years or more. This will help you save money significantly as LED exit signs are powered by rechargeable batteries and don’t need to be replaced.
LED exit signs are presented in a variety of types. They can be cast aluminum, thermoplastic or upscale Edge-Lit. Depending on your environment’s conditions and interior decor, you should choose an option that meets your requirements. As always, feel free to contact Emergency Lighting’s industry leading customer service team with any questions.
According to emergency evacuation rules, you should mark each doorway going outside with a clear exit sign. This will reduce the impact of an emergency and help people find an exit when the lights are out. To enhance its efficiency, you should follow a number of exit sign best practices:
– Exit signs should be clear and visible from a long distance to attract attention immediately.
– They should show the way to the nearest exit and let people get there as soon as possible. Along with the word “EXIT”, people should see an arrow indicating the direction.
– Avoid using other signs on the door because it may confuse people. The use of mirror near exits signs is not recommended either.
– If the door does not lead to an exit, put a sign saying that it is not an exit or indicate that it is a closet, basement, etc.
– Make sure your exit sign will be illuminated even in the case of power-outages.
– It is very important to check the operational efficiency of your exit sign regularly. Schedule and perform regular check-ups to make sure it works properly.
– If your exit signs require batteries to operate, make sure you regularly charge or replace them.
Once followed, all the above mentioned tips will ensure better exit signs functioning and prevent harm that may be caused by an emergency situation.
If you want to install electric exit signs, you may eventually find that it is quite an expensive solution. However, there are two affordable alternatives to installing traditional hard wired exit signs. Even though they have their pros and cons, you may find them more effective and their installation process less time-consuming.
Photo luminescent Signs
These signs do not need the use of electricity or batteries to work. They work with the help of photoluminescence and can thus be illuminated in the dark. In terms of installation, it is very easy and does not need an access to an outlet. Photo luminescent signs do not consume power and this significantly reduces their maintenance cost. They are often called “glow-in-the-dark” lights.
Photo luminescent signs receive energy from the external light in order to be able to function properly. When the light is minimized, the sign becomes visible and glows. The signs can be installed everywhere once there is enough external light to absorb it.
Self-Luminous Tritium Exit Signs
This kind of signs is used without electricity power and any external light. They work with the help of radio luminescence and clearly show an exit sign in the dark. Again, no need in electricity power means extremely easy installation and the reduced cost on its maintenance.
If power consumption is an issue, the use of alternative exit signs solutions will help you solve a number of problems. Starting from installation cost to power consumption fees – you can avoid it by considering two options mentioned above. They are extremely reliable and will get you ready for a possible lights-out emergency situation.