Topics January 3, 2019
Emergency Lighting: Safe in Case of Emergency

If the power fails and the light goes out at home, it can be very inconvenient, but it does not necessarily create a significant security risk. The situation is markedly different in a shopping center, in a cinema, at the airport or in a production facility – wherever large groups meet, a sudden lighting failure can quickly lead to critical situations. Even more dangerous is when there is a real emergency occurring at the same time, such as a fire or heavy smoke. In such cases, lighting must be used to ensure that all the people inside the building can find the quickest way out.

Legal Requirements

Understandably, there are a large number of standards and directives in Germany that set specific minimum requirements for emergency lighting, including the type of building and how it's used. Important regulations include:

  • DIN EN 1838 – Lighting applications – Emergency lighting
  • DIN EN 50171 – Central safety power supply systems
  • DIN EN 50172 – Emergency escape lighting systems
  • DIN EN 50272 – Safety requirements for batteries and battery systems
  • DIN EN 62034 – Automatic test systems for battery-operated emergency lighting for escape routes
In addition, other standards and legal requirements may be relevant. And these must always be verified for each individual installation.

Replacement lighting and safety lighting

Emergency lighting is basically divided into the two areas of replacement lighting and safety lighting.

Replacement lighting is used when there is no immediate danger to people present due to a power failure. Essentially a backup, it replaces the failed original lighting to maintain regular or, at the very least, limited operation. Typical applications for replacement lighting are surgery rooms in hospitals, control rooms in power plants or above machines and in plants that are running costly production processes.

Safety lighting has another goal. It is installed wherever the integrity of people is in focus and a building or building area must be evacuated as quickly and safely as possible. In this function, safety lighting fulfills three tasks:

  • Safety lighting of escape routes
    to provide the fastest route to the exit from any specific location in the building
  • Anti-panic lighting
    to prevent panic and to reach the nearest emergency route
  • Safety lighting for workplaces with function-specific hazards
    to safely complete a presently running and potentially dangerous work process and then be able to leave the building via the escape routes.

In the event of a power failure, emergency lighting will inevitably have to resort to an alternative source of energy, usually a battery. According to their decentralized, semi-central or centralized arrangement in the building, a distinction is made between three emergency lighting systems.

Battery Systems

Single-Battery Systems
For single-battery systems, each safety light is decentralized and has its own battery. The advantage here is that no additional special cables must be laid for installation, lowering construction costs. This results in higher costs during operation. Because: On average, the life of the batteries is exhausted after four years. Depending on a building’s size and the number of safety lights, battery replacement can be a lot of work– especially since the lights are not always accessible and technical support is sometimes needed. In addition, regular statutory audits need to be ensured either manually or through wireless safety lights, for example. For smaller and listed buildings, where major changes to the building structure should be avoided, single-battery systems are often an adequate solution.

Central Battery Systems with Power Limitation
Low-power systems (LPS), often referred to as power-limited battery supplies, are a semi-decentralized alternative. An LPS does not supply a whole building with battery power, but only a certain building area. As a rule, several low-power systems are needed in one object. The connected load is 1,500 watts for one hour or 500 watts for three hours. The advantage of this solution is that no fireproof cables need to be laid throughout the building beyond the area to be supplied, allowing buildings to be gradually renovated and put into operation. In addition, no separate space is required for the LPS batteries. 

Central Battery Systems without Power Limitation
As with LPS, the battery life of central power systems (CPS) is at least ten years on average. After a more complex installation, special cables to the luminaires have to be laid from a central room in the building; however, the ongoing operation is particularly economical. Unlike safety lights for single-battery systems, those for centralized and semi-decentralized solutions are much more compact. For buildings with a high design standard, this aspect can also be decisive. In addition, individual lighting settings can be made, for example via DALI.

Testing and Maintenance – Automated or Manual
Whether a single- or central battery system, the best emergency lighting is worthless if it does not work properly in an emergency. In order to ensure long-term reliability after initial installation, the various standards and guidelines call for routine testing and maintenance that's quite extensive. The effort can be quite considerable. The time intervals for such tests vary according to the maintenance and testing that must be performed. They range from the viewing of the status LED for each luminaire daily to switching to emergency mode monthly and the annual check of the battery charger.
Automatic test systems can lend a tremendous amount of assitance for this work. If such a test system must be additionally installed wireless or wired for single-battery light systems, the implementation with central battery systems (LPS and CPS) is much easier. With them, the status of the entire system can be viewed from a central location. Tests are regularly performed and documented after prior programming. If there is an error, the technician will be informed with a detailed error description and exact position information – via message on screen, e-mail or text message.

Modern Emergency Lighting with DALI and LED

Modern central emergency lighting systems take advantage of automatic tests. They also use the same lights for both general and safety lighting. This saves costs and while simultaneously creating an elegant ambiance.

And three technologies are required for this: On the one hand, lighting control gears – especially electronic ballasts (ECGs) – must be individually controllable – due to its manufacturer independence, the DALI protocol is ideal for this purpose. On the other hand, the luminaires must be suitable for generating different light scenarios – at this point, many things have become possible with the advent of LED technology.

Automation technology is needed to create an emergency lighting scenario from a general lighting system in an actual emergency. It ensures that previously defined scenarios in which certain LEDs are lit in a certain strength and color are stored and retrieved as needed.
Because these scenarios can be created in such an individual way, from the anti-panic lighting to the safety lighting of escape routes, all needs can be met. The configuration occurs either via a user's own web interface or – after previous integration – over the proprietary building management system. However, achieving this requires an open automation system with a high degree of interface diversity.