What a CAN/ULC-S537 Verification Actually Involves

Sources checked August 2026

Quick answer

The scope, in the standard's own framing

CAN/ULC-S537 establishes inspection and test procedures

for the purpose of verifying that the fire alarm system is installed in conformance with the design, and with CAN/ULC-S524 … and that it performs all of its intended functions.

(Standards Council of Canada)

Read that as three separate tests, because that is what it is:

1. Does it match the design? The drawings, the specification, the fire alarm matrix.
2. Does it comply with S524? Independent of what the drawings said. A design error does not become compliant because it was built faithfully.
3. Does everything actually work? Every intended function, including the ones that involve other systems responding.

A system can pass one and fail another. Built exactly to drawings that were wrong is a fail. Compliant wiring that does not actually operate the dampers is a fail.

Where the requirement comes from

In Ontario, verification of a new fire alarm system is a Building Code requirement, and it survived the 2025 code replacement with its article number intact.

3.2.4.5. Installation and Verification of Fire Alarm Systems (2) Fire alarm systems shall be verified in conformance with CAN/ULC-S537, "Verification of Fire Alarm Systems," to ensure satisfactory operation.

Division B Table 1.3.1.2 pins that to CAN/ULC-S537:2019, listing 3.2.4.5.(2) and 3.2.4.20.(10) as the provisions that reference it.

Quoted from the 2024 Building Code Compendium Vol. 1, Division B, printed pages 100 and 32, the 16 January 2025 update, the most recent free consolidated text.

What changed on 1 January 2025. O. Reg. 332/12, the old full-length Building Code, was revoked (O. Reg. 163/24, s. 3). The Building Code in force is now a one-page regulation adopting NBC 2020 as amended by the "Ontario Amendments to the National Building Code of Canada 2020", currently dated 17 July 2026. Two things follow that catch people out:

• The article number did not move. 3.2.4.5 is still 3.2.4.5. An older document citing it is not automatically stale.
• The edition did move. O. Reg. 332/12 designated S537-13. The current Building Code designates S537:2019. Verifying to the wrong edition is the live risk now, not citing the wrong article.

Getting the text is harder than it should be. Ontario no longer publishes the full-length Building Code on e-Laws. The free consolidated Compendium (Vol. 1 · Vol. 2) is the 16 January 2025 update and sits behind the amendment document in force. The amendment document itself is distributed by email request only, from Ontario.Amendment.Document@ontario.ca. NBC 2020 is free from NRC. Full breakdown in which ULC edition applies.

The grandfathering has a condition people miss. O. Reg. 332/12 still governs construction permitted on or before 31 December 2024 (or with substantially complete drawings by then and a permit application by 31 March 2025) but only if construction began within six months of the permit being issued (O. Reg. 163/24, s. 2(2)). Ontario's own plain-language timeline omits that condition. A stalled pre-2025 permit may have quietly moved to the new code, and the new edition.

The Fire Code invokes S537 in exactly one place: Article 9.9.4.12.(2), in Part 9 (Retrofit), Section 9.9 Hotels, "Where a fire alarm system has been installed, extended or modified as required by this Section, the system or portion of the system shall be tested in conformance with CAN/ULC-S537". There is no general Fire Code verification duty.

Note what these provisions do and don't say. They name the standard the work must conform to, not the person. But that is only half the picture in Ontario: once a system is in service, the Fire Code does name the qualification. See our guide on who can legally do what in Ontario.

Who signs it

This is genuinely different across the country, and assuming the Ontario answer applies elsewhere will get you in trouble.

Alberta: the mandatory rule is narrower than the usual summary

Alberta names no qualification for performing an S537 verification. There is no mandatory provision in the Alberta codes that says who may carry one out. That is the part most summaries get wrong, and it is worth being precise about.

What is mandatory:

• NBC(AE) 2023 Division C, Article 2.4.1.4.(1)(c): for a building not exempted by Article 2.4.1.1., a registered professional must design the fire alarm system, carry out the field reviews and witness the verification. Witnessing it is not the same as performing it.
• NFC(AE) 2023 Division C, Article 2.2.4.3: the installer and inspector qualification. Installation is electrician-only: an Alberta journeyperson electrician certificate issued on or after 1 September 1991, or an earlier or Canadian Red Seal certificate plus a fire alarm course recognised by the Provincial Fire Administrator. Inspection, testing, maintenance and signing accept those same electrician routes or CFAA Fire Alarm Technician certification.

What is not mandatory: the often-quoted line that verifications are "generally the responsibility of a licensed engineering professional" sits in Note A-2.2.4.3.(1). The code states that its notes "are included for explanatory purposes only and do not form part of the requirements." Quoting that note as a requirement overstates it.

Alberta uses the NBC (2023 Alberta Edition and NFC) 2023 Alberta Edition, both in force 1 May 2024, and references the same CAN/ULC editions Ontario does, S524:2019, S536:2019 and S537:2019. The current joint interpretation on existing systems is STANDATA 23-BCI-011 / 24-ECI-009 / 23-FCI-006, "Existing fire alarm systems," March 2025 (Alberta Municipal Affairs · index of joint interpretations).

Alberta's own rule on older bulletins, verbatim: "Once a new code comes into effect, all existing STANDATAs are deemed obsolete. However, they are still valid for evaluating code compliance of existing structures…" So a pre-2024 STANDATA number on an old report is not automatically wrong for that building, but it is not the current document, and it should not be cited as the live rule. Full detail in fire alarm rules in Alberta.

Ontario: a qualification for maintenance work, and no named verifier

For new construction, verification is a Building Code matter. Article 3.2.4.5.(2) names the standard, CAN/ULC-S537:2019 per Division B Table 1.3.1.2, not a qualified person. That was true under the revoked O. Reg. 332/12 and remains true under O. Reg. 163/24.

But once a system is in service, the Fire Code takes over and it is explicit. Division C, Article 1.2.1.2.(1)(a) requires anyone who "repairs, replaces or alters components of a fire alarm system" (or performs annual tests or inspections) to have "successfully completed a program or course acceptable to the Fire Marshal." The regulation names no program; the Fire Marshal's published list currently holds two, CFAA and ECAO Certi-Fire. Division C 1.2.1.2.(2) also permits an unqualified person to do the work under on-site supervision by a qualified person, with no more than two supervised persons at a time. (Ontario e-Laws)

The Division C requirement bites on the alteration work itself, repairing, replacing or altering components is clause (c) of Article 1.2.1.1. It does not extend to the S537 verification: Division C 1.2.1.1 lists only annual tests and inspections (6.3.2.2), interconnection testing and maintenance (6.10.1.1), and repair/replacement/alteration. Verification under 9.9.4.12.(2) is not on that list, and no Ontario provision names a qualification for performing it. Ask the AHJ.

That gap is an Ontario one, not a Canadian one. Newfoundland and Labrador does name a qualification, and its wording expressly includes verification: NLR 45/12, s. 8(3) bars any person from "maintenance, repair, inspection, testing or verification of an installed fire alarm and detection system" unless, in the fire commissioner's opinion, they possess the necessary tools and testing equipment, have passed certification examinations to his satisfaction and have received the applicable licences. A licence, not a course, and verification is named in the clause, see Fire alarm rules in Atlantic Canada.

What triggers a verification

New installations, obviously. Alterations are where it gets genuinely unclear, and it is worth being precise about what is settled and what is not.

Neither Ontario code sets a threshold. Building Code Article 3.2.4.5.(2) requires fire alarm systems to be verified in conformance with CAN/ULC-S537 and says nothing about modifications. The Fire Code invokes S537 only at Article 9.9.4.12.(2), for hotel retrofit work required by Section 9.9, and Sentence (3) of that article says "Sentences (1) and (2) do not apply to existing fire alarm system components." Nothing in either Ontario code says that an alteration re-triggers a full verification. The scope rule lives inside CAN/ULC-S537 itself, which is paywalled, and in practice it is a permit and AHJ question. We are not going to invent a device count, a percentage or an "any change at all" rule to fill that gap.

Individual AHJs do take positions, and they vary. Calgary's regulation bulletin is the bluntest Canadian example, and note what it is: a municipal bulletin in Alberta, not a code requirement, and not binding in Ontario.

All alterations to existing fire alarm systems are required to be verified in accordance with CAN/ULC-S537.

That is Calgary's stated position, regardless of the scope of the alteration or the age of the system. The referenced interpretation defines "alterations" to include maintenance, repair, upgrading and replacement, and the same bulletin requires a building permit for all fire alarm alterations. It is one municipality's rule, quoted here because it is unusually explicit, not because it applies to your job. (Calgary Regulation Bulletin RB06-064)

Markham requires a building permit before modifying or replacing a panel, annunciator or control unit. Note that a permit requirement is not the same as a verification requirement, though a permit is often what brings the Building Code duty into play. We have not linked a source for this one; confirm the current requirement with the municipality.

Which code edition applies to the alteration

Sourcing caveat: the table below reflects AHJ interpretation practice, not text we can point to in either Ontario code. Neither the Building Code nor the Fire Code states these rules. Treat them as a description of how the question is commonly resolved, and confirm with your AHJ.

That top row is worth remembering. Swapping a failed device for an identical one does not drag the whole building up to current code. Swapping it for a different device, in a building whose use has changed, might.

Alberta's certificate carries an invalidation notation

Alberta's verification certificate template carries a notation that subsequent modifications invalidate the certificate. That is a notation on the Alberta form, not an Ontario rule, and not a statement in either Ontario code.

Where it applies, the certificate in the document binder may already be void and nobody will have told the owner. On any unfamiliar building, "what has been changed since" is a more useful question than "when was it last verified."

The report

The format is fixed

Since the 2019 editions, the report forms moved out of the appendix and into the body of the standard. That changed them from a suggested template into a requirement. Two independent Canadian trade sources state the rule in identical words; we are relying on those secondary sources here, not on the standard itself, which is paywalled:

Tests or inspections may not be reworded or revised in order or format.

You may add your logo. You may recreate the form in your own software. You may not change the structure, the wording, or the order.

Calgary goes further, and Ontario AHJs are heading the same way: all sections must be completed, partial reports are rejected outright, and inapplicable sections must be marked "N/A" rather than deleted or left blank.

What it contains

The report is reported to cover: system information; control units and transponders; field devices; power supplies; circuit fault tolerance; ancillary devices; interconnections to fire signal receiving centres; deficiencies; and recommendations: with device-level records tied to address and zone, and battery test results including capacity calculations. (Certi-Fire)

That is a Canadian trade source rather than the standard itself, so treat the list as indicative of shape rather than definitive.

Two structural points reported consistently by Canadian trade sources, not quoted from the standard itself, which is paywalled:

Circuit fault tolerance gets its own reporting. The 2019 edition of S524 requires that a single open, short or ground fault not disable field devices in more than one NBC-required zone, across all circuits leaving the control unit. Verification has to demonstrate that, which means imposing faults, not just confirming devices operate.

Deficiencies are separate from recommendations. Those are the two current finding types. A deficiency is a compliance failure creating an obligation to rectify. A recommendation is your advice, which the owner may decline. The older term Remark was deleted and replaced with Comments in S537-19; the free source for that, and the limits on how far it reaches, are set out on that page. Legacy forms still in circulation may show a Remarks block.

And what verification is not

It is not the annual inspection. That is CAN/ULC-S536, it is calendar-driven, and it recurs for the life of the building. A passing annual is not a verification and does not stand in for one.

It is not integrated testing. CAN/ULC-S1001 covers the interfaces between systems, fire alarm to fire pump, dampers, elevator recall, door hold-open release. You can verify a fire alarm perfectly and still not have demonstrated that the elevators recall.

It is not maintenance. Alberta's interpretation treats maintenance (the removal or replacement of inoperative devices) as its own activity.

Full breakdown in our guide to the four ULC standards.

One thing we could not source

How many devices must be tested.

We could not find, from any accessible Canadian source, the S537 device-count or percentage rules, or a formal definition of "partial verification."

What we can say: Calgary rejects partial reports: but that is about report completeness, not about a permitted partial-verification scope. Those are different questions and we are not going to conflate them to fill a gap.

If you are planning a verification, get this from your own copy of S537 or from your AHJ. It is the one number in this article we cannot give you, and we would rather say so than guess.

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Verification is also the task at the centre of the CFAA registration practical exam, which is a full S537 verification performed one-on-one with an invigilator. What that exam actually involves.

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