When you add access control to a door, one of the first questions is what the lock should do when power is lost. That choice is called fail safe or fail secure.

Fail Secure

A fail secure device stays locked when power is removed and unlocks when power is applied. If the power goes out, the door stays secure from the outside. People inside can still leave, because the lockset or exit device on the inside opens mechanically.

Fail secure is the usual choice for electric strikes on exterior doors, storerooms and fire-rated doors.

Fail Safe

A fail safe device unlocks when power is removed and locks when power is applied. If the power goes out or the fire alarm cuts power, the door is free to open.

Fail safe is used where the door must open without power, such as some stairwell doors and doors that must release on fire alarm.

Electric Strikes

Many electric strikes can be switched between fail safe and fail secure in the field. Fire-rated doors must stay latched during a fire, so they generally use fail secure strikes that carry a fire-rated listing. Check the product specifications and your local code.

Maglocks

Electromagnetic locks are always fail safe, because the magnet only holds while it has power. Codes generally require a request-to-exit sensor or button and release on fire alarm when a maglock is used on an exit door.

Quick Comparison

• Power lost, fail secure: locked from outside, free exit from inside.
• Power lost, fail safe: unlocked.
• Fire-rated doors: usually fail secure strikes with a fire listing.
• Maglocks: always fail safe.

Not sure what you need? Call B&H Depot at (561) 826-6018.