Depending on the location of the energy source, there are two ways of powering emergency lighting: self contained and slave.
- Self contained emergency lighting is connected to the normal mains power. In the event of an emergency the luminaire switches over to a battery located in the actual luminaire. As such, each luminaire has its own power source.
- Slave emergency light fittings are powered by a centrally located energy source, a slave power box. Several luminaires are connected to a single power source. In the event of a mains power failure the slave power box switches over to emergency power supply.
The most important advantages and disadvantages are listed briefly below. Many factors play a role in deciding which of the different types of emergency lighting systems to choose. VanLien has listed all of these in detail for each building phase, from design, installation, operation (inspection & maintenance) to renovation.
Self contained versus slave. What to choose?
Self contained:
- Less vulnerable. Self contained emergency light fittings operate autonomously. In the event of a failure of the energy source only one luminaire fails and not the entire system.
- More flexible. System can also be expanded easily at a later stage.
Slave:
- Maintenance of slave luminaires is generally easier. A slave luminaire contains fewer components.
- Installation is often time consuming and expensive. Slave emergency light fittings have to be connected via separate cabling.
Exceptions…
When would you choose a slave emergency lighting system in preference to a self contained system?
- In rooms with a high ambient temperature. The lifespan of the batteries fitted in self contained luminaires can decline considerably.
- In situations in which high light output is required. For example, at workplaces with an increased risk, specific processes have to be terminated first in emergencies.
- When emergency light fittings are difficult to reach. With slave emergency lighting the batteries are located in the cabinet. It is therefore not necessary to change the batteries individually for each luminaire.