Software-Based Fire Trips Are Dangerous And May Impact Mandated Fail-Safe Standards In Access Control Systems.
Software-Based Fire Trips Are Dangerous – According to Ken McKeon of Jack Fuse, software-based fire trips can compromise an access control system’s mandated fail-safe mechanisms.
We have been receiving feedback from security integrators that competing companies and/or clients have insisted that a software or firmware-based fire trip is adequate for the release of doors during a fire alarm. We argue that a software fire trip is a fundamentally flawed mechanism for fail safe access control systems.
Operationally, a software/firmware trip is an interface to the fire indicator panel that uses an access control system input and programming to unlock doors in the event of a fire alarm.
The Australian National Construction Code 2022, volume one, part D3D26 covers fire trips. To paraphrase: any fail-safe lock in a required exit path, must unlock automatically on activation of the fire system (dry or wet). With a few exceptions (like detention centres) this covers most doors in most buildings.
Take note of the word ‘automatically’. Accepted industry best practice is to use a fail-safe connection from the FIP to a dedicated relay that directly cuts the lock power circuit. There are several reasons why this is accepted and why software-based trips are a dangerous practice in comparison.
The Australian Standard AS1670.1 (Fire Systems) section 3.15 mandates that electric lock release during a fire alarm condition be failsafe.
The rules the argument rests onTwo clauses, one word doing the workWhat the code and the standard actually ask for — before you weigh how a fire trip is wired.
National Construction Code 2022 · Vol OneD3D26 Operation of latchA door in a required exit normally has to open without a key. Sub-clause (3)(d) lets it stay locked if it is fitted with a fail-safe device that automatically unlocks it when a sprinkler, smoke or other detection system suitable under AS 1670.1 activates.Read Part D3 at ABCB →
AS 1670.1 · Fire detection & alarm systemsSection 3.15, as cited by the authorElectric lock release during a fire alarm condition must be fail-safe. The article does not name an edition: AS 1670.1:2024 is current, and the NCC 2022 calls up the 2018 edition — check the clause in the one that applies to your job.AS 1670.1:2024 at Standards Australia →
automaticallyThe author’s case turns on this word: a release that depends on firmware, programming and a network link working at the time of the alarm is not, in his view, automatic or inherently fail-safe.
Sources. D3D26 paraphrased by SEN from the NCC 2022 text published by the ABCB. The AS 1670.1 clause reference is Ken McKeon’s. NCC 2025 is being adopted state by state from May 2026, so clause numbering may differ on newer jobs. Not legal or certification advice.
Software-Based Fire Trips Are Dangerous 4Software-Based Fire Trips Are Dangerous 5
A software-triggered fire release depends on software, firmware, hardware, programming and intercommunication via Ethernet and/or RS485. Each of these dependencies is a weakness in the system that could cause the fire trip to become inoperable during an emergency.
Break the chain · interactiveOne fire alarm, two release pathsPick what goes wrong. See which doors still unlock — on a site with one fire signal and three door controllers.
Hardware trip 3 steps
1Fire panel alarm contactfail-safe output
2Dedicated relayhard-wired
3Lock power circuit cutevery fail-safe lock
Not in this path: controller firmware, trip programming, Ethernet / RS485, server.
Software trip 7 steps
1Fire panel alarm outputone signal per building
2ACS input, controller 1input + programming
3Controller firmwaresoftware / firmware
4Fire-trip programmingthe trip rule
5Ethernet / RS485 linkcontroller to controller
6Server or peer relaymulti-controller sites
7Lock outputs, C1–C3drive locks open
Every lock power circuitD1D2D3D4D5D6
C1C2C3D1D2D3D4D5D6
SEN illustration of the author’s argument — a dependency map, not a failure-rate model. Six doors and three controllers are a hypothetical site. The case is Ken McKeon’s; his company, Jack Fuse, makes hardware fire-trip interfaces. A hardware trip still has to be wired, commissioned and tested correctly.
In most cases, there is only 1 fire trip signal to the access control system per building, however, there is often more than 1 access controller. If the network or other connection (RS485) between door controllers fails, then the fire trip will not work for some or all doors.
Consider, too, that if the trip is transferred from 1 controller to another via software, this leaves the fire trip system vulnerable to server and/or, again, network outages.
An input-based fire trip may not work during firmware, software or network updates but a fire trip must work automatically at all times.
Further, network and server failures would be likely during an actual fire.
And it is hard to test/confirm that a door is set failsafe. A software trip will also unlock a fail-secure door.
Making matters worse, programming errors can lead to some or all doors not unlocking during a fire. Imagine a scenario where a tech has changed settings and accidentally, post-install, deletes the fire trip functionality. How would you know?
Similarly, a software-triggered fire trip is a security vulnerability. An error could result in all doors being unlocked.
Software-Based Fire Trips Are Dangerous
Testing of a software-based fire trip is problematic. How do you trigger the test? And will that perfectly match a real-world scenario?
The above problems are greatly reduced/eliminated using a failsafe, hardware-based interface. It is simple to test, cost-effective, reliable and easier to fault-find.
A software-based fire trip can never be 100 per cent failsafe. In fact, it is guaranteed not to work under several scenarios.
In my professional opinion a software-based trip fails to meet code because it is not inherently failsafe and it cannot guarantee, due to the above-mentioned problems, that doors will automatically unlock during a fire system activation.
In comparison, Jack Fuse Power Port modules such as the Jack Fuse PP8FR provide a failsafe, hardware-based fire-trip interface.
Some people will argue with me on the points I have raised here - I would ask those people if they would feel comfortable explaining their rationale to the coroner.
You can find the Australian Standard AS1670.1 here, learn more about Jack Fuse here or read more SEN news here.
*Ken McKeon is founder and managing director of security electronics manufacturer, Jack Fuse.
Before the next fire testALARM →
Five questions for whoever commissioned your fire tripsDrawn from the problems Ken McKeon raises. Send them to your integrator, fire contractor or facilities manager — the answers tell you which kind of trip you have.
1Is our fire trip a fail-safe hardware interface, or an access control input and a programmed rule?2If the network or RS485 link between controllers drops, which doors still release?3Does the trip still work while firmware or software is being updated?4If someone deleted the trip in a later programming change, how would we know?5How is it tested — and does the test match a real alarm?
Named in the article · Jack Fuse Power PortThe hardware fire trip, and every manual for itKen McKeon gives the PP8FR as his example of a fail-safe, hardware fire-trip interface. Here’s the module — and the install note for each version, current and legacy.
Current · V6
Power Port 8FRFire-tripped power distribution moduleEight individually fused outputs with status LEDEach output selectable: fire power or standard powerDry contact or voltage fire trip inputFire alarm monitoring output12 or 24VDCDIN rail mountWhere the fire trip landsA fail-safe signal from the fire panel — a normally closed contact or a DC voltage — goes to the FT terminals. Each fused output is then set to FIRE or standard power.
PP5FR-UNIFive outputs; fits Gallagher and Inner Range footprintsInstall note (PDF) →
As published by Jack Fuse. Features, images and manuals are Jack Fuse’s; PDFs open on jackfuse.com. SEN has not tested these modules. Full Jack Fuse manual library →
“Software-Based Fire Trips Are Dangerous And May Impact Mandated Fail Safe Standards In Access Control Systems.”
Questions & AnswersSoftware fire trips: what installers and specifiers are askingWhat is a software-based fire trip?
An interface where the fire indicator panel signals an access control system input, and the system’s programming then unlocks the doors. The alternative the article describes is a fail-safe connection from the panel to a dedicated relay that cuts lock power directly.
Why does the author say a software fire trip is not fail-safe?
Because the release depends on software, firmware, hardware, programming and Ethernet or RS485 communications all working during the alarm. He argues each is a point of failure, and that network and server failures are likely in a real fire.
What does the NCC require for locked doors in a required exit?
Under NCC 2022 Volume One, D3D26(3)(d), a required-exit door may stay locked only if a fail-safe device automatically unlocks it when a sprinkler, smoke or other suitable detection system activates. NCC 2025 is being adopted state by state, so check the edition for your job.
What does AS 1670.1 say about lock release during a fire alarm?
The author cites section 3.15 of AS 1670.1 as requiring electric lock release in a fire alarm condition to be fail-safe. The article does not give an edition; AS 1670.1:2024 is current, so confirm the clause in the edition your project is designed to.
Does the NCC actually say a fire trip must be hard-wired?
The D3D26 text does not mention relays or software. It requires a fail-safe device that unlocks automatically. That a software trip fails this test is the author’s professional opinion; your certifier or fire engineer makes the call on a specific job.
How do you test a fire trip properly?
The article raises the question — how do you trigger the test, and does it match a real alarm — but does not set out a procedure. It argues a hardware interface is simpler to test and fault-find. Agree the test method with the fire system maintainer.
Who wrote this, and do they sell a hardware alternative?
Ken McKeon, founder and managing director of Jack Fuse, an Australian security electronics manufacturer. The article names the Jack Fuse PP8FR Power Port module as an example of a fail-safe, hardware-based fire-trip interface.
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