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 under one of the recognized special-locking provisions in IBC Section 1010.1.9. Those provisions are separate arrangements with separate conditions, not one thing: controlled-egress doors in I-1 and I-2 occupancies, elevator-lobby doors, delayed-egress locking systems, and sensor-release (access-controlled) egress doors each have their own subsection. Subsection numbering inside 1010.1.9 has moved between editions, so work from the edition your jurisdiction adopted.

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, and (e) loss of power to the access-control system.

Get the 30 seconds the right way round. On the sensor-release arrangement, the manual unlocking button next to the door must directly interrupt power to the lock, independent of the access-control electronics, and the door must then stay unlocked for at least 30 seconds. That is a minimum hold-open, protecting the person who pushed the button. It is not a delay before the door releases. A delay before release is a different arrangement entirely, delayed egress, which holds an occupant at the door for its own permitted interval and carries its own signage, alarm, and occupancy conditions. Mixing the two on a drawing is how a submittal comes back rejected.

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-secure electric strike. Egress here is mechanical, the inside lever retracts the latch whether the strike has power or not, which is the same reasoning that makes a fail-secure strike compliant behind a panic device. Fail-safe on this door would unlock the suite on every power blip for no code benefit. Verify the lockset actually gives free egress from inside before you spec it; if it does not, the door must be fail-safe.
• Stairwell door where the code requires re-entry (high-rise stairways in particular): fail-safe electric strike with controlled re-entry override on fire-alarm signal. Pull the re-entry requirement from the adopted IBC edition; it lives in the egress-door provisions of Chapter 10 and, for high-rise, in the high-rise section of Chapter 4.
• 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.