Victaulic seals leak when the system fails

In regular operation, emergency lighting blends in relatively inconspicuously into the overall picture.

What is emergency lighting?

If the light fails in public buildings, workplaces or commercial premises, it can quickly lead to panic and disorientation. Therefore, emergency lighting is mandatory in all places where there are usually many people. Depending on the area of ‚Äč‚Äčapplication, emergency lighting has to fulfill several functions at the same time. It therefore includes the emergency lighting and the replacement lighting. The safety lighting should provide general safety and help to avoid accidents and to ensure safe exit of the building. It is divided into anti-panic lighting, lighting for escape routes and rescue facilities, and safety lighting for workplaces with particular hazards. Replacement lighting is a special case. It ensures that operations can continue for a limited period of time and during this time it completely replaces general lighting. Replacement lighting plays a role where economically or technically important work still needs to be done.

The aim of safety lighting is to ensure sufficient visibility and orientation so that evacuation measures can be carried out and people can safely leave the corresponding danger zones. The anti-panic lighting is intended to prevent panic and ensure that the escape routes can be found effortlessly. On the escape routes, illuminated or backlit escape signs with directional instructions point to the emergency exit and enable safe exit from the building.

In the event of a power failure, the emergency lighting is an important guide.

The moon as a measure of brightness

The European standard EN 1838 stipulates how bright the emergency lighting must be as a minimum requirement: Emergency lighting must be at least twice as bright as the moon on a clear, starry night. This lights up with 0.01 lux on a clear night and with 0.25 lux on a full moon night. This results in a value of 0.5 lux for the anti-panic lighting and a value of 1 lux for the safety lighting of escape routes that the ratio of the highest to the lowest illuminance does not exceed 1:40 and that a CRI> 40 is ensured.

Safety power sources

In addition to individual batteries and central battery systems, group battery systems as well as various emergency power generators - safety power generators, rapid standby units, immediate standby units - or a separate network are available as safety power sources. In public buildings, workplaces and commercial spaces, you will mostly find single batteries or central battery systems. If the emergency lighting is based on individual batteries, each luminaire contains a battery with a separate emergency lighting system consisting of an operating and a charger. Central batteries combine the capacities of several batteries at nodes and can provide 220 V DC voltage. All operating devices suitable for DC according to EN 50172 are suitable for emergency lighting. A distinction is made between devices with a fixed output voltage and dimmable devices. In DC operation, the output of dimmable devices is dimmed to a lower value, usually to 15 percent. Older specifications mandate central battery systems for larger buildings. But these specifications are now considered obsolete. Both from a technical point of view and with regard to currently applicable standards, there are no longer any objections to using emergency lighting systems with self-contained systems in larger buildings.

Fig .: The LED emergency light model EM-AP 004 (left) with its wide beam angle is especially suitable for anti-panic lighting. EM-ER 004 (right) meets the requirements for lighting escape routes.

Fig .: EM powerLED (left): The emergency lighting control gear is connected here via a separate circuit; EM converterLED (right): If a combined control gear is used, an emergency lighting unit is sufficient for normal and emergency lighting operation.

Operating modes and test procedures for emergency lighting

There are different operating modes for the emergency lights: Standby mode only applies to the emergency lights. In contrast, luminaires in escape signs or luminaires that cover both general lighting in mains operation and emergency lighting in battery operation are in continuous operation.

In order for the emergency lighting to work reliably in the event of a power failure, it must be tested at the prescribed intervals. Different test routines are available for this:

Manual test: In this case, the power failure is caused by manually interrupting the power supply and then a visual check is carried out.

Automatic self-test: This test is done decentrally. Every emergency lighting device carries out the test itself at times of low risk in accordance with EN 62034. One also speaks of a car test system.

Centrally controlled and monitored test procedures: A central control and monitoring system activates the test here; the test results are also displayed and documented centrally. The actual test intelligence is located directly in the respective emergency lighting devices.

LED in emergency lighting

In addition to emergency lighting components for fluorescent lamps, there are also emergency lighting components for LEDs. The advantages are obvious: LEDs are extremely economical, energy-efficient light sources with a long service life. They take up very little space and give luminaire manufacturers and lighting designers completely new design options. Thanks to their high efficiency, smaller batteries are sufficient, so that the entire system can also be smaller and more cost-effective than with conventional light sources. LED light is available immediately with almost no time delay and shines just as brightly as the light from conventional light sources with lower energy consumption. The long service life of LED light sources reduces the maintenance intervals and thus also the maintenance costs. In addition, the directional light of the LED makes it easier to adapt the radiation characteristics to the respective lighting tasks. A wide beam pattern is particularly suitable for anti-panic lighting. With lenses and reflectors, however, it is also possible to bundle the LED light and thus, for example, adequately illuminate the median of escape routes.

Possible solutions with LED

Application-specific emergency lighting: For anti-panic lighting, for example, with a ceiling height of 3 m, a separate 1 W LED module integrated in a light or in an extra housing with a wide beam angle is sufficient to achieve the 0.5 lux required here. Escape routes must mainly be illuminated in the middle. A 1 W LED module is also suitable here, but its light is bundled by means of reflectors and lenses. In this way, with the same ceiling height and the same light point spacing, the required double illuminance of 1 lux is easily achieved. LED strips are usually used in escape signs that backlight the sign or inject the light via edge feed.

Separate, integrated LED for emergency lighting

If LED boards are used for general lighting, additional LEDs can be integrated on the boards, which are used exclusively for emergency lighting. These emergency lighting LEDs are connected to the emergency lighting control gear via a separate circuit and only provide light in the event of a power failure. Therefore, they are not subject to normal aging and are extremely durable. This emergency lighting system is particularly suitable for use in countries in which the standards prescribe separate light sources for emergency lighting, e.g. in Spain, Italy or France.

Standard LED modules for emergency lighting

This emergency lighting solution corresponds to the tried and tested solution with fluorescent lamps and combines general and emergency lighting. While all LED modules are connected in mains operation, a relay switches a selectable number of LED modules to emergency lighting operation if required. The emergency lighting control gear detects the forward voltage of the connected LED modules and regulates the LED current to the highest possible value with which the connected batteries achieve the specified operating time. Around 10 percent of the full output is then available for adequate emergency lighting. This emergency lighting solution benefits from all the advantages of LEDs. For example, switching operations for the legally required tests do not affect the service life of the LED light sources, which is definitely the case with fluorescent lamps. The variety of available LED modules from various manufacturers - linear modules, surface modules as well as compact modules such as spotlights or downlights - gives luminaire manufacturers a great deal of design freedom. Emergency lighting solutions below 60 V (SELV) allow particularly flexible and cost-effective designs because they do not need any additional covers for protection against accidental contact.

Reliable emergency lighting systems in public buildings ensure that there is no panic and that people can leave the building safely.

Advantages of LED emergency lighting solutions

In addition to the well-known advantages such as small dimensions, longevity, reduced maintenance requirements and high efficiency, LED light sources provide light immediately. This pays off particularly in workplaces with particular risk. Here the light must be available at full strength within 0.5 seconds. These requirements cannot be met with fluorescent lamps due to the time delay when starting the lamp. Up to now, the much less efficient halogen lamps have been used here. LED-based emergency lighting systems not only meet these requirements, they even exceed them: They deliver 100 percent of the required illuminance within milliseconds.

Conclusion

As in all lighting sectors, LEDs are also gaining ground in emergency lighting. Their properties such as small size, durability, energy efficiency and low energy consumption recommend these light sources especially for this lighting area. They can help to reduce maintenance costs and save operating costs. Complete systems consisting of an LED module, control gear and control system that are perfectly matched to one another are particularly recommended.

Additional Information:

Photos: Tridonic
Text: Reinhard Pfatschbacher, Product Engineer, Tridonic GmbH & Co. KG, Dornbirn (AT), www.tridonic.com