Fire alarm matrix

A fire alarm input output matrix is a table that states, for every input the system can see, exactly what the system must do about it: inputs run down the rows, outputs across the columns, and a mark where they meet is a required sequence of operation. Reading one row across gives you the complete response to that input, which is why a table catches gaps that a written sequence of operation hides. It is not required by name in any Canadian code, but it becomes binding because a CAN/ULC-S537 verification tests the installed system against its design documents. On an addressable system the panel prints its own version, the input to output correlation report, and the two are compared.

Last updated: September 2026

What a matrix is

Rows are inputs, meaning anything that can put the system into an off normal state: a manual station, a smoke or heat detector, a sprinkler flow switch, a valve tamper switch, a duct detector, the alarm stage switch at the panel. Columns are outputs, meaning anything the system can make happen: alert, alarm, annunciator zone, transmission to the monitoring station, elevator recall, air handler shutdown, door holders, magnetic locks, or a supervisory indication and nothing else.

A mark in a cell is a requirement, not a preference. Prose hides gaps. A table makes an empty row obvious at a glance.

Where it gets its authority

No Canadian code article says "produce a matrix". What makes it binding is what happens at the end of the job. UL's May 2023 presentation to the Building Officials Association of British Columbia described the CAN/ULC-S537 scope as inspection and test procedures for verifying that the fire alarm system is installed in conformance with the design, and stated that for addressable systems a printout of the input to output software correlation report forms part of the verification documentation.

That correlation report is the panel's own version of the matrix. If the programming and the consultant's matrix disagree, the difference gets printed and handed to the person signing the certificate, and a cell nobody could build becomes a deficiency with a company name beside it. The process end to end is in what an S537 verification actually involves.

Four things to check in every row

Signal type. Alarm, supervisory or trouble. A waterflow switch produces an alarm because water is moving. A valve tamper produces a supervisory because a person moved a handle. A tamper row with the alarm column ticked is an error, and a good share of matrix mistakes are really signal type mistakes. See alarm, supervisory and trouble signals.

Stage. On a two stage system, does this input produce the alert or the alarm? Ontario Building Code Article 3.2.4.4 makes the general alarm sound automatically if the alert signal is not acknowledged within 5 minutes of its initiation, with an exception for Group B, Division 2 occupancies. The escalation is conditional on acknowledgement, not on the clock alone, and a matrix that treats it as a plain timer is describing something the Code does not say.

Scope of notification. Building wide, or the floor of origin plus the floors above and below? That changes the wiring, not just the programming.

Consistency with the riser. Every relay needs a column, and every column needs a device to drive it.

What goes wrong

Cells nobody confirmed. Whether elevator recall follows the lobby and machine room detectors only or any common alarm, and whether magnetic locks release at alert or at alarm, vary between designers, and both arrangements are in service on Canadian buildings. Those are questions for the consultant in writing rather than assumptions carried over from the last job.

Then the ordinary failures: an ancillary device shown on the riser with no row of its own, a matrix output with no module to drive it, and a matrix that was never revisited after a tenant fit-up changed the zoning.

Neighbouring terms

The riser diagram says what is connected; the matrix says what it must do. The two are read together, against the floor plans and the specification. Our full treatment of both, with a worked Canadian example walked through input by input, is in how to read a riser diagram and an input output matrix.

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