Emergency lighting and job maintenance: How about that?

Emergency lighting is just like insurance: essential – even mandatory – and indispensable in the event of disasters. But under normal circumstances, it is a topic that does not arouse a little enthusiasm. Emergency lighting should be there, it should work, and preferably not involve too much hassle and cost. Because of the last point, it is wise to pay serious attention to it during construction or replacement.

There are roughly two options when designing emergency lighting fixtures: centralized or decentralized. It’s not a matter of taste, like choosing between Coca-Cola or Pepsi. What is the best solution for the building and organization depends on the local situation, cost considerations, and the preferences of the user or property manager. This is why it is a good idea to consider the different characteristics of centralized and decentralized solutions before we discuss job retention in relation to emergency lighting.

decentralized emergency lighting

With decentralized emergency lighting, all the lamps, escape path indicator and escape path lighting are individually connected to the nearest voltage. Each unit has its own battery and charger. One advantage is that installation and electrical connection are usually simple. It’s a matter of pulling and connecting. One drawback is that – due to the limited capacity of the internal battery – there is only a limited amount of light available in emergency mode. This can be a challenge when lighting vulnerable workplaces in an emergency, where a lot of light is required to safely stop machines, for example. For users, the biggest practical drawback is that the batteries need to be replaced every few years. Since emergency lighting is not always in the most accessible location, this is often a tedious and labor-intensive task.

Central emergency lighting

With central emergency lighting, the lights are powered and controlled from a common emergency lighting center. Creating such an installation requires more planning and preparation, for example due to its cables. On the other hand, there are the advantages of centralized emergency lighting: batteries usually last longer, maintenance is easier and faster to perform, higher light levels are possible, and lamps are less sensitive to low and high temperatures than ‘central’ luminaires with their own battery. This makes the central emergency lighting system also suitable for applications in high or low ambient temperatures (up to -40°C).

Function-retaining and fire-retardant compartments

An important point to pay attention to when installing central emergency lighting is the concept of functional retention. Job retention means that the installation must continue to operate for a period of time of at least 30 minutes (usually 30 minutes) after a fire has broken out. However, job retention isn’t so much about the room in flames; Everyone should be able to get out of there within 30 seconds. It mainly concerns the situation in the other parts. The power supply and cables must be strong enough that the installation in other compartments will continue to operate during that time period.

NEN 1010 specifies requirements (construction) for cabling for central emergency lighting installations and the building ordinance specifies requirements for, among other things, the fire resistance of the building and escape paths. The most important point is that the fire in the fire compartment should not affect the emergency lighting in the other compartments. Thus, job retention plays no role in decentralized emergency lighting. These installations do not rely on power from or through another compartment.

Job retention in practice

In short, the principles of emergency central lighting are very simple in practice. Cables through a compartment require functional retention, while cables in a compartment do not. 30 minutes of functional retention is sufficient in most cases and in compartments with more than one centrally supplied emergency lighting unit, fixtures must be connected alternately with at least two separate power circuits.

The functionality can of course be preserved by applying specific solutions to the cabling system. These cables consist of a functional safety that is mounted on a suitable substrate or bracket using the correct mounting materials. However, it is also often possible, especially in new constructions, to achieve function retention through architectural solutions. For example, if the cables are installed into concrete structures in the wall, the floor, or deep in the ground, you also have the required retaining function without the need for a lot of specific installation materials while retaining the function.

Furthermore, by making smart choices in configuring centralized emergency lighting fixtures, you can greatly reduce the need to retain function by utilizing lamp substations for each compartment.

It is even possible to completely eliminate cabling while maintaining functionality by using separate small emergency lighting centers for each compartment, the so-called Low Power Systems (LPS). In this case, just as with decentralized emergency lighting, no maintenance is required at all because the emergency lighting in each compartment does not depend on the rest of the building.

Balancing choices and outcomes

Emergency lighting is not rocket science, but it is important to carefully consider options and consequences when installing or replacing emergency lighting. What is the best option for our organization in this case? Of course, the cost aspect also plays a major role. Therefore, also include long-term costs, not only purchase and construction, but also maintenance and replacement. By the way, one solution is not necessarily better than the other. Sometimes decentralization is the best solution, sometimes centralization.

Edwin de Graaf, Emergency Lighting Product Manager at Eaton (and orderly Lunch and Learning Program)

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