Electric door lock in case of fire: quiescent current versus operating current

Besides fire-resistant and smoke-resistant glass, there are other factors to consider when it comes to fire prevention. Consider, for example, power outages. What happens to an electric door lock if the power goes out? This depends entirely on the door's purpose. Do you want the door to remain accessible or closed during a power outage? We'll discuss the options with you and when to choose one or the other.

Why lock a door electrically?

An electric lock keeps a door closed until the access control system releases it. This can be applied, for example, to doors leading to areas where unauthorized access is prohibited. Employees can enter the area using a tag or pass, while others remain outside.

The operation of quiescent current (voltage-free unlocking)

Quiescent current is also called voltage-free unlocking. This is the most commonly used locking method. The lock is continuously powered, but if the power fails, for example, due to an emergency, the door will automatically release. Therefore, the power supply for this lock should not have a battery backup.

In the event of a fire, all doors will open with static current, allowing everyone to quickly exit the building without needing an access pass or tag. This way, you'll never find yourself faced with a closed door if you accidentally leave it in the cafeteria.

The operation of live current (de-energized interlock)

Also called de-energized. With fail-safe current, the lock must be energized to open the door. If this voltage is lost, the door cannot be opened. This fail-safe current can be used on doors that require additional security. Think, for example, of areas containing valuable materials, dangerous machinery, or flammable substances. The door remains closed to prevent escalation.

In cases where a door in addition to a fire door also serves as an emergency exit, the door often has a push bar or an anti-panic lock so that the door is still accessible from the emergency exit side.

Fire safety and access control via System Flex

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