Electronic Strike vs Maglock, Fail-Safe vs Fail-Secure Selection

Why this matters

Commercial access-controlled doors lock and unlock electrically, not mechanically. The two dominant electric lock types are the electric strike (replaces the door frame strike with a powered version) and the electromagnetic lock or maglock (a powerful magnet on the frame, an armature on the door, bonded together by current). Each comes in fail-safe (unlocks on loss of power) or fail-secure (locks on loss of power) configurations. The selection is driven by NFPA 101 Life Safety Code, IBC Chapter 10 egress requirements, the local fire marshal's interpretation, and the customer's security needs. Getting the configuration wrong creates either a code violation (egress impaired) or a security failure (door pops open during a brownout). This article is the selection decision.

NFPA 101 and IBC egress framework

NFPA 101 Section 7.2.1 requires every door in a means of egress to be openable from the egress side with one operation, without keys, tools, or special knowledge, and without a delay greater than the standard.

IBC Section 1010.1 mirrors the requirement.

The corollary: a door on a means of egress that locks on the egress side must unlock automatically on loss of power, on fire-alarm activation, on a manual release device that meets the standard, or on a recognized exception (the controlled-egress door in I-1 and I-2 occupancies, the elevator-lobby door under specific code conditions, the access-controlled egress door per IBC 1010.1.9.8 with delayed-egress hardware).

The practical consequence: any access-controlled door on a means of egress must be configured fail-safe (unlocks on power loss). Fail-secure configurations are limited to doors that are not on a required means of egress (storage rooms, IT closets, mechanical rooms) or to doors with separately approved free-egress hardware on the egress side (a fail-secure electric strike paired with a panic device that mechanically retracts the latch is the typical compliant configuration).

Electric strikes

An electric strike replaces the mechanical strike plate in the door frame with a strike that releases the latch when energized (fail-secure) or releases when de-energized (fail-safe). The mechanical lockset remains; the latch hits the strike whether powered or not.

• Fail-secure electric strike: locked on power loss, unlocked when energized. Used when the door must remain locked during a power failure (storage room, IT closet, fail-secure tenant entry).
• Fail-safe electric strike: unlocked on power loss, locked when energized. Used on perimeter doors on means of egress where loss of power must release the door.

Electric strikes preserve the mechanical lockset's egress function: the lever or panic device on the egress side mechanically retracts the latch and opens the door whether the strike is powered or not. This makes electric strikes the default choice for code-compliant access control on egress doors when paired with the right lockset.

Voltage: typical 12 V DC and 24 V DC; some legacy 24 V AC. AC operation makes the strike buzz; DC operation makes it click silently. Match the strike to the access-control power supply.

Continuous duty vs intermittent duty: continuous-duty strikes can be held energized indefinitely; intermittent-duty strikes are sized for momentary release. Specify continuous duty if the access control system holds the strike energized for free passage windows.

Maglocks

A maglock places a high-strength magnet on the door frame and a steel armature on the door. When the magnet is energized, the armature is held against the magnet with 600 to 1500 lbs of holding force. When the magnet is de-energized, the door is free.

Maglocks are inherently fail-safe: power loss equals no magnetic force equals door free. This is the only mode they operate in.

The code complication: NFPA 101 and IBC require that a maglock-secured door release on (a) power loss, (b) fire-alarm activation, (c) sprinkler-system activation, (d) a manual release device on the egress side meeting specific criteria (typically a push button to release plus a 30-second delay-egress timer, or a request-to-exit motion sensor plus a touch-bar release), and (e) loss of power to the access-control system.

Maglocks on a means of egress require specific code-compliant release hardware. The local fire marshal's interpretation is the final word; some jurisdictions tolerate motion sensor REX (request to exit) plus an emergency push button to release, others require a UL 294 listed delayed-egress controller. Document the AHJ's interpretation in the project file.

Selection by door type

• Perimeter door on means of egress with panic device: fail-secure electric strike or electrified lockset that retracts the latch mechanically on egress side.
• Tenant suite entry on means of egress with a lever lockset: fail-safe electric strike (power-on locks the strike, power-off releases).
• Stairwell door (re-entry required by IBC 1023.4 on high-rise): fail-safe electric strike with controlled re-entry override on fire-alarm signal.
• Sensitive interior door not on a means of egress (server room, vault, secure storage): fail-secure electric strike or electrified lockset; maglock is permissible but inferior to a mechanical lockset for security.
• Glass storefront door on means of egress: maglock is the common solution because the all-glass door has no place for a strike-and-latch; fail-safe by definition, with REX and emergency release.

Power supply and battery backup

Access-control power supplies should be UL 294 listed (access control system units). Battery backup sized for the standby duration the AHJ requires (typically 4 hours minimum, longer in some critical facilities).

Fire-alarm interface: a contact closure or dry contact from the fire-alarm control panel releases the maglock or fail-safe strike on alarm. The interface is typically a Form C relay in the access-control power supply, wired to a designated FACP zone.

Documentation for the AHJ

The plan submittal to the fire marshal includes:

• Door schedule with each access-controlled door identified.
• Lock type and configuration (fail-safe or fail-secure) per door.
• Release method (mechanical egress hardware, REX, push button, delayed-egress timer).
• Fire-alarm interface diagram.
• UL listings of the lock, power supply, and access-control panel.

The AHJ's approval stamp is the inspection gate.

References

• NFPA 101 Life Safety Code, Sections 7.2.1 Doors and 7.2.1.6 Special Locking Arrangements.
• International Building Code, Sections 1010.1 Doors and 1010.1.9 Door Operations.
• UL 294 Standard for Access Control System Units.
• BHMA / ANSI A156.25 Standard for Electrified Locking Devices.
• BHMA / ANSI A156.31 Standard for Electric Strikes and Frame Mounted Actuators.