Which feature is essential for an emergency lighting system?

An emergency lighting system is designed to provide illumination during a power outage or emergency situation, particularly in the context of evacuating a building safely. The essential feature of illuminating paths of egress is critical because it ensures that occupants can see their way to exits, reducing the risk of injury and improving the effectiveness of evacuation procedures. This illumination is necessary to guide individuals through potentially hazardous or unfamiliar environments when visibility is compromised, such as during a fire or other emergency.

While other options may describe certain attributes or functionalities that can be beneficial in specific situations, they do not capture the primary purpose of emergency lighting. For example, using solar power could be advantageous for sustainability but is not a requirement for an emergency lighting system. Similarly, reliance on a fire alarm for activation is not universally applicable, as emergency lighting should also function independently during a power failure. Lastly, being connected to the main power supply might support operation, but emergency lighting systems typically have backup power sources, making them operational during outages. Consequently, the ability to illuminate paths of egress remains a fundamental requirement for maintaining safety in emergency situations.