What is the minimum illumination time provided by a battery-powered lighting system for personal evacuation?

The minimum illumination time provided by a battery-powered lighting system for personal evacuation is typically set at 5 hours. This standard is based on the need to ensure adequate visibility during emergencies, allowing individuals to navigate safely to exits in the event of a power failure or other emergencies. A 5-hour duration strikes a balance, providing sufficient time for evacuation without unnecessary resource expenditure, as longer illumination times would require larger batteries and additional constraints on system design.

In emergencies, maintaining safety and facilitating a timely evacuation are critical; therefore, 5 hours is considered a practical minimum that allows for these objectives to be effectively met.