In a fire condition, how quickly must door-hold devices release?

• A. 1-2 seconds
• B. 60-120 seconds
• C. 0-5 minutes
• D. 10-30 seconds

Answer: (D)

When a fire is detected, the aim is to restore a closed path quickly to contain smoke and flames while still allowing people to evacuate. Door-hold devices are designed to keep a door open under normal conditions, but they must release when the fire alarm signals so the door can close and help compartmentalize the building. The required release window of 10 to 30 seconds after the fire signal gives a balance: fast enough to prevent major fire spread, but not so fast that doors slam shut before people can move. Times much shorter, like 1–2 seconds, would be overly abrupt and less practical in real evacuations, while longer intervals such as 60–120 seconds or minutes would let fire and smoke spread more before the door closes.