Emergency egress lighting is required to provide lighting for a duration of how many minutes?

Emergency egress lighting is crucial in ensuring that individuals can safely exit a building during an emergency situation, such as a power failure or fire. The requirement for this lighting is defined by building and safety codes, which typically state that emergency egress lighting must remain operational for a duration sufficient to facilitate a safe evacuation.

The correct duration, which is 90 minutes, aligns with standards set by organizations such as the National Fire Protection Association (NFPA) and the International Building Code (IBC). These guidelines specify that emergency lighting systems should provide adequate illumination for at least 1.5 hours. This duration accounts for the time it may take for occupants to find their way to safety, especially in larger buildings or where visibility could be significantly impacted by smoke or darkness.

Other durations, such as 60 minutes, 75 minutes, or 120 minutes, may not provide the necessary time frame dictated by the prevailing safety standards and may reduce the safety of occupants during an emergency evacuation. Adhering to the specified 90 minutes ensures a balance between practical evacuation time and the operational capacity of the emergency lighting system.