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Frequently Asked Questions
What is the difference between a request-to-exit device and an exit button?
A request-to-exit device senses that someone is leaving and suppresses the alarm; an exit button is pressed deliberately and releases the lock.
The distinction matters because they solve different problems. Without a REX, a door opened from the inside looks identical to a forced door and generates an alarm every time.
A REX is typically a passive infrared sensor above the door, or a switch in the door handle, and in most configurations it shunts the door contact rather than unlocking anything - the mechanical handle does the opening.
An exit button is used where the lock physically prevents the door opening, such as a magnetic lock. Pressing it removes lock power for a set time.
Many doors have both: a REX so normal exits are not alarmed, and a button for the case where the lock has to release.
Neither is an emergency device. That is a third product with a different wiring requirement.
Does an emergency release have to be wired independently?
Yes. Its entire purpose is to release the door when the access control system cannot or will not, so it must break the lock supply directly.
An emergency release wired as an input to the controller is not an emergency release. If the controller has failed, hung or lost power to its logic, nothing happens.
The correct arrangement puts the unit's contacts in series with the lock power so operating it removes power regardless of what any other device thinks.
Most systems also feed a monitoring signal to the controller so the operation is logged and alarmed - but that signal is additional to the direct break, never a substitute for it.
Placement, height, colour and labelling are usually prescribed by local fire regulations rather than left to preference.
Test the actual release, not the monitoring input, at commissioning and at every periodic inspection.
Where should exit devices be mounted?
Within comfortable reach of anyone using the door - including wheelchair users - and close enough to the leaf that the action is obvious under stress.
Accessibility regulations in most jurisdictions set a mounting height range and a maximum reach, and those figures differ between territories, so check the local rule rather than copying a previous project from elsewhere.
Distance from the door matters for usability. A button on the far side of a corridor is not found by someone leaving in a hurry.
Emergency releases are normally required to be adjacent to the door they release and clearly identified, often in a prescribed colour.
Avoid positions where the device can be reached from the insecure side - through a letterplate, a gap under the door, or an adjacent glazed panel. This is a well-known attack and it is defeated by position rather than by product.
On double doors and lobbies, decide which leaf carries which device before first fix, not after the frames are in.
How is a door forced or held open detected?
With a door position contact, monitored by the controller, and two separate timers - one for forced, one for held.
A door contact reports open or closed. Combined with the access decision, the controller can tell the difference between a legitimate opening, a door opened without any credential, and a door still open too long afterwards.
Forced-door detection catches an opening with no valid credential and no request to exit. It is the most useful alarm the system produces.
Held-open detection catches propping. The timer needs setting to real traffic - too short and deliveries generate constant alarms, too long and it never fires.
A local sounder that warns before the alarm is raised usually solves propping without involving anyone.
Fit contacts inside the protected area, with the cable route concealed. A contact that can be reached and magnetically defeated adds nothing.
Are delayed egress doors permitted?
Sometimes, under strictly defined conditions - and the conditions differ enough by jurisdiction that this always needs a local answer.
Delayed egress holds a door for a short, fixed period after someone attempts to leave, sounding an alarm meanwhile. It is used in healthcare, retail and secure care settings.
Where it is permitted at all, the rules typically specify the maximum delay, mandatory signage, an immediate release on a fire alarm signal, and an override for the authorities.
Some jurisdictions prohibit it on certain occupancies entirely.
It is never a way to make an ordinary secured door harder to leave through. Specifying it for convenience rather than for a recognised clinical or safety reason is the mistake that gets found at inspection.
Get written confirmation from the authority having jurisdiction before designing around it.
What should happen to doors during a fire alarm?
Escape route doors must release, and the interface that makes that happen has to be independent of the access control software.
The standard arrangement takes a volt-free signal from the fire alarm panel and uses it to remove power from the locks on escape routes, in hardware.
Relying on the access system to receive a message and unlock doors introduces a dependency on the software, the network and the server, none of which are life-safety rated.
Not every door releases. Doors that are not on an escape route may stay locked, and some doors are held open by magnets that must release to let the door close. Both behaviours are driven from the fire system.
The interface has to be tested as part of the fire alarm test, with the doors physically checked rather than the relay observed.
Document which doors do what. On a large building this is the single most commonly misunderstood part of the installation.
Can exit devices be monitored and logged?
Yes, and they should be - an exit that leaves no record is a hole in the audit trail and hides misuse of emergency devices.
Exit button operations, REX activations and emergency release operations can all be fed to the controller as monitored inputs.
Logging them lets the system distinguish a legitimate exit from a forced door, and it shows the pattern when an emergency release is being used routinely because the normal exit is inconvenient.
Emergency release operation should raise an alarm as well as a log entry. It is not a routine event and treating it as one defeats the point.
Tamper monitoring on the devices themselves catches interference before it matters.
None of this monitoring may condition the release itself. The device releases the door first and tells the system afterwards, in that order.