Commercial Building Inspector B2Public Safety and Special ConstructionEasy
A building inspector is reviewing the plans for a new three-story Group B office building. The building has a total occupant load of 400. In the event of a power failure, how long must the emergency lighting system be capable of providing illumination for the means of egress?
- A120 minutes
- B60 minutes
- C30 minutes
- D90 minutes
Show answer & explanationAnswer & explanation
Correct answer: D. 90 minutes
Emergency lighting systems for means of egress in most commercial buildings, including Group B occupancies, are required to provide illumination for a minimum of 90 minutes in the event of power failure, as per IBC Section 1008.3.5.
Why the other options are wrong
- A. 120 minutes is typically for specific high-risk or large-scale facilities, not a general minimum for Group B.
- B. 60 minutes is not the standard minimum duration required by the IBC for egress lighting.
- C. 30 minutes is generally insufficient for emergency egress lighting in commercial buildings.
Emergency Lighting Duration
The minimum time period for which an emergency lighting system must remain operational after a power failure, specifically for illuminating the means of egress.
- Required for means of egress.
- Minimum 90 minutes duration.
- Must provide initial illumination for the first 1.5 hours.
- Ensures safe evacuation during power outages.
Memory trick: When the lights go out, 90 minutes of glow helps you flow.