Request-to-Exit (REX) Sensors: What They Do—and What They Don’t

A request-to-exit device tells an access-control system that someone is leaving through a controlled door. Its job depends on the door hardware and approved sequence of operation. On many doors with mechanically free egress, the REX does not need to unlock the door at all.

What a REX device can do

A REX input can come from a motion detector, push button, panic hardware switch, electrified lockset or another listed device. The controller can use that input to:

• temporarily suppress a forced-door alarm while the door opens;
• record an authorized egress event in the audit trail;
• start or coordinate a door-held-open timer;
• trigger an approved release sequence when the door design requires one.

The exact function should be documented for each opening. A generic “unlock on motion” rule is not appropriate for every door.

Free egress usually comes from the door hardware

With a fail-secure electric strike, electrified lockset or electrified exit device, a person should normally be able to leave using the inside lever or panic hardware without presenting a credential. The access-controlled side remains secure while the mechanical egress function works independently.

In that arrangement, the REX commonly shunts the forced-door alarm and improves event reporting. It is not the sole means of escape and does not need to remove power from the lock merely because someone approaches the door.

Why the door-position switch matters

The REX indicates intent to exit; the door-position switch confirms whether the door actually opened and closed. Using both allows the system to distinguish among normal egress, a forced opening and a door held open too long.

• REX only: the system knows someone approached or operated the egress hardware.
• Door position only: the system knows the door changed state but may not know why.
• REX plus door position: the controller can apply the intended alarm and timing logic.

Maglocks and sensor-release doors need special design

Electromagnetic locks are fail-safe: loss of power releases the lock. Doors that rely on sensors, buttons or fire-alarm interfaces for release can have additional life-safety requirements and must be designed as a complete listed and approved opening.

Avenger Security generally prefers fail-secure electric strikes, electrified locksets or motorized latch-retraction hardware on standard commercial doors when the application allows. Maglocks are reserved for special configurations supported by the door, egress hardware, approved plans and the authority having jurisdiction.

Do not make the REX the single point of egress

A motion sensor can be blocked, misaligned or affected by the environment. A push button can also be misunderstood or installed in the wrong location. Required egress should not depend on one unverified software input when mechanically free egress hardware is the appropriate solution.

Any fire-alarm interface, emergency release, delayed-egress or controlled-egress function must follow the approved design. Do not assume every fail-secure lock must unlock on a fire alarm; many mechanically free-egress openings remain secure from the outside without obstructing exit.

Commissioning checklist

• Verify the listed hardware, handing, voltage and fail mode.
• Confirm free egress with the access controller online, offline and without normal power.
• Test REX, door-position, forced-door and held-door events separately.
• Confirm that the audit trail describes each event accurately.
• Test battery backup and any approved emergency-release interfaces.
• Document the final sequence of operation and obtain required inspections.

For hardware comparisons, read our commercial electric-lock guide. You can also review access-control planning and costs or contact Avenger Security for a door-by-door evaluation.