Commercial Building Inspector B2Public Safety and Special ConstructionEasy
A building inspector is reviewing the emergency lighting system design for a new mercantile building (Group M). The building has an occupant load of 350 and is equipped with an automatic sprinkler system. How long must the emergency lighting system remain operational after a power failure, according to IBC?
- A120 minutes
- B90 minutes
- C30 minutes
- D60 minutes
Show answer & explanationAnswer & explanation
Correct answer: B. 90 minutes
According to IBC Section 1008.3.5, emergency lighting facilities shall be arranged to provide illumination for not less than 90 minutes in the event of a power failure. This requirement applies to all occupancies where emergency lighting is mandated, regardless of sprinklers or specific occupant load within the general scope.
Why the other options are wrong
- A. 120 minutes is a longer duration than typically required by IBC for general emergency lighting, though some specialized systems might exceed this.
- C. 30 minutes is not a standard duration for emergency lighting in commercial buildings under IBC.
- D. 60 minutes is not the minimum required duration; 90 minutes is the standard.
Emergency Lighting Duration
Emergency lighting systems must maintain illumination for a specified minimum duration following a power outage to facilitate safe egress.
- Required in most commercial and public buildings.
- Standard duration is 90 minutes.
- Ensures visibility for safe exit.
Memory trick: When the lights go out, 90 minutes keeps the path bright.