Ask the Experts | Fail Safe vs. Fail Secure

“Fail safe” and “fail secure” often need explanation in the industry of security and access control. Both are functions of an electronic access control lock in the situation where it has lost power or is triggered by a fire alarm.

Functions:

Fail Safe: the lock defaults to an unlocked state when power is lost or fire alarm is triggered. Requires power to lock.

Fail Secure: the lock defaults to a locked state when power is lost or fire alarm is triggered. Requires power to unlock.

Depending on the function of the lock, its application, and location of the building’s egress exits, and/or whether it’s a stairwell exit will determine if it should be fail safe or fail secure.

Unfortunately, there isn’t a simple rule to follow for all lock types and functions. However with some understanding, the basics for each function’s justification as “fail safe” or “fail secure” will be easier to remember.

Egress Stairwell Fire-rated Doors

When using an electric strike on an egress stairwell exit it is required in the event of a fire alarm for it to be set to “fail secure” according to NFPA 80 requirements. Therefore, fire-rated doors on stairwells must be latched closed in the event of fire and electric strikes (but not the locksets themselves) on fire-rated doors must default to a locked state (fail secure). This allows the door’s lock to latch closed and allows a user of the door’s lockset (set to “fail safe”) to freely egress.

Electromechanical Lock Doors

As a rule, most electromechanical locks typically “fail safe” in the event of power loss or a triggered fire alarm. In the instance where an electromechanical double-cylinder is being used, then “fail safe” should not be used in application with any door that is required for egress—an exception being double-cylinder classroom security locksets designed to allow free egress. Institutional function locksets are sometimes double cylindered and specialized to “fail secure”, but their proper applications can vary according to the presiding authorities and/or building code.

Electrified Panic Hardware Trim

Electrified panic hardware trim usually works on the opposite side of panic hardware, or fire exit hardware, as a lever operated trim. However, since it’s on the opposite side of the door, its requirement to be “fail safe” or “fail secure” differs from application to application.

On a re-entry door for a stairwell, “fail safe” electrified panic hardware trim is used because of the need to be able to come and go freely from either side of the door in the event of a power failure or triggered response.

Alternatively, any other usage of electrified panic hardware would typically declare it to be “fail secure.”

Electrified Latch Retraction (EL) & Electromagnetic Locks

An electric latch retraction is a function found on panic hardware or fire exit hardware that allows for latch retraction when power is applied. When power isn’t applied, the latch is extended. So by design, electric latch retraction functions are typically “fail secure.”

Alternatively, electromagnetic locks are typically only designed to be “fail safe.” When power is cut to an electromagnetic lock, it changes to an unlocked state. Because this only happens when power is removed from the mag-lock, it requires a release device/mechanism for egress. Examples include request-to-exit switch in panic hardware, pushbutton actuator and sensor combination, and fire alarm/sprinkler system trigger.

No Hard, Fast Rules

“Fail safe” and “fail secure” settings are always going to be subject to the presiding authority creating situations where an application may require different settings. It’s important to research building codes in your own presiding authority before installing “fail safe” or “fail secure” devices.

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