Standby lighting

In areas like hospital operating theatres or factories with constantly supervised processes, some activities must be continued in an unchanged manner, even in an emergency – while maintaining the same lighting conditions.

When an emergency occurs, it is often not possible to immediately leave the place where you are working. This happens most often when performing activities that, if interrupted, could endanger someone's life or cause irreparable damage of high-value equipment. Such situations may take place in hospital operating theatres, in factories with complex and constantly supervised processes, or in control rooms that require continuous maintenance.

Safely interrupting potentially dangerous activities

It’s natural for people to want to finish those types of activities, or to interrupt them in a way that will significantly reduce any risk to health or property. At the same time, it should be made very clear during the training process that this type of behaviour is only justified based on the responsibility entrusted to the employees in this regard. In addition, appropriate safety measures must be prepared for these types of situations, including the proper emergency lighting.


Ensuring the same lighting conditions in an emergency

Standardised standby lighting is a part of the emergency lighting that is meant to make it possible to continue work in a substantially unchanged manner during an emergency. This means that it needs to provide the same lighting conditions from the emergency power supply system as those provided by the general lighting. At the same time, it should be noted that switching between the general and emergency lighting mode must happen with a time frame defined by the needs of the performed task and should be agreed upon with the final user of the space.

Taking this into account, in order to ensure the appropriate parameters for the emergency standby lighting, in the overwhelming majority of cases, the same lighting fixtures can be used as for the general lighting. The only condition is that their light sources must be able to immediate re-ignite after a momentary power interruption.

EU guidelines require proper evacuation conditions for all occupied workspaces

Important standby emergency lighting design principles to remember about for areas with processes that need to be continued:

  • the fact that the lighting intensity is defined by the task that is being performed in a given space, but its duration time is determined by the user of the facility, and not by normative regulations
  • however, if standby lighting is also used as typical emergency lighting, a minimum standard duration time should be ensured
  • due to the required quantitative parameters, standby lighting is often implemented using central power supply systems
  • it’s important to remember that including a central power supply system in the design entails a number of serious consequences. At the investment stage, this means that flame-retardant wiring must be used, while at the stage of using the facility, it means that daily inspections must be performed and appropriate entries must be included in the report book.


Emergency lighting requirements:

Type of emergency lighting  task / activity area

Illuminance level (Emin) / Luminance level (Lmin)

Diversity ratio (Ud)



Time until 50% / 100% illuminance is achieved
Standby lighting 100% of the general lighting parameter for the visual task In accordance with EN 12464 In accordance with EN 12464 As required for the task As required for the task
Standby lighting additionally used as escape route lighting 100% of the general lighting parameter for the visual task In accordance with EN 12464 In accordance with EN 12464 As required for the task, no less than 1 h As required for the task