Fail-Secure Locks: Safe Egress & Knox Box Fire Access - Avenger Security

Fail-Secure Locks: Safe Egress & Knox Box Fire Access

Best practice: Specify fail-secure locks that still provide free egress from the inside and give the Authority Having Jurisdiction (AHJ) fire department access via a Knox Box® or approved rapid-access device. This approach maintains perimeter security while protecting life safety. (Informational only—always follow local code/AHJ.)

Fail-Secure vs. Fail-Safe—When to Use Each

  • Fail-secure: Stays locked on power loss; interior egress remains free. Common for perimeter/security doors where you must maintain protection.
  • Fail-safe: Unlocks on power loss; often used where code or life-safety requires immediate, unobstructed evacuation (e.g., some mag-lock applications).

Most facilities use a mix of both based on door use, occupancy type, and the AHJ’s guidance.

AHJ / Fire Department Access (Knox Box)

Provide a rapid-access box (e.g., Knox Box®) at the main entrance with labeled keys/credentials so first responders can enter without forcing doors. Coordinate placement and contents with your local fire department.

Design Guidelines

  • Egress first: Exiting must never require keys, codes, or special knowledge; emergency egress is one motion.
  • Clear hardware intent: Pair the lock with the correct exit device/lever set; match the door/frame and voltage.
  • Power & supervision: Use listed power supplies with battery backup; supervise critical circuits.
  • Document openings: Note which doors are fail-secure vs. fail-safe and why; include AHJ sign-off.
  • Test regularly: Verify egress, access, and rapid-access box procedures with drills.

Video: Fail-Secure Concept in Action

Short demo: fail-secure lock behavior with free egress and responder access.

Plan Your Openings

Need help selecting the right hardware per opening? Explore Access Control, review Fire & Life Safety, or request a site visit to coordinate with your AHJ.

Back to blog