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Critical vs non-critical defects in fire safety inspections

Last reviewed 25 October 2026 · Based on AS 1851-2012 (Amendment 1) and NSW guidance

AS 1851-2012 sorts what a routine service finds into three classes: critical defects, non-critical defects and non-conformances. The class decides who must be told and how quickly, and how urgently the owner needs to act. This page explains each class in plain language, with examples, and covers how to record them.

In short

Critical defect The system is out of action, and people would likely be at serious risk if a fire broke out. Tell the owner on site, and follow up in writing within 24 hours.
Non-critical defect Something is faulty or degraded, but the system should still do its job. Tell the owner within a week.
Non-conformance The system works, but a record or detail that servicing relies on is missing or wrong. Tell the owner within a week.

The three classifications

The classifications are set out in clause 1.5.6 of AS 1851-2012, and the reporting requirements are in clause 1.17.1. This is a plain-language summary. Read the clauses themselves in your licensed copy.

Class	In plain language	When the owner must hear about it
Critical defect	The system is out of action. If a fire broke out, people in the building, or in part of it, would likely be at serious risk.	On site, before the technician leaves, or as soon as possible after. Then in writing within 24 hours, and again each time the same defect is found.
Non-critical defect	A component is faulty or degraded, but it is not expected to stop the system working when needed.	Within a week.
Non-conformance	The system works, but something that routine servicing depends on is missing or wrong, such as design or baseline information.	Within a week.

A routine service activity done outside its tolerance window is also recorded as a non-conformance (an "out-of-tolerance activity"). See tolerances.

Not the same as "critical fire safety measures"

In NSW, a critical fire safety measure is a Regulation term for a measure that the fire safety schedule says must be assessed more often than every 12 months. It triggers supplementary fire safety statements. A critical defect is an AS 1851-2012 term for a fault found during servicing. A critical measure can have no defects, and any measure can have a critical defect.

Deciding which class

Work through two questions, then apply the criteria in the relevant section of the standard and your own judgement:

Is the system out of action, such that people would likely be at serious risk if a fire broke out? If yes, treat it as a critical defect.
If not, is something actually faulty or degraded? If yes, it is a non-critical defect. If the system works but information is missing or wrong, or the work was out of tolerance, it is a non-conformance.

Some tests come with their own acceptance criteria. For example, the hydrant hydrostatic test method in the NSW good practice guide sets out when a result is a pass, a non-critical defect or a critical defect.

Who to tell, and how fast

The technician notifies the responsible entity, usually the building owner or their agent, on the timeframes above. Defects and their classifications also appear in the yearly condition report (clause 1.17.2). For a critical defect, don't stop at the conversation on site. Send the written confirmation within 24 hours, and reconfirm the defect each time it is found again until it is fixed.

What to do with each

Critical defect

Building Commission NSW says a critical defect must be addressed as soon as possible, and the owner should consider having mitigation in place in case there is an emergency while the system is inoperable.
In the NSW guide's lightning-strike case study, a fire indicator panel was damaged beyond repair. The strata manager first contacted the council, verbally and in writing. While they waited for the council's advice, the owners told Fire and Rescue NSW, their insurer, their legal adviser and the residents, arranged security patrols of all floors from 6 pm to 6 am and installed temporary manual fire fan controls. When the council had not replied after 7 days, they replaced the panel like for like, and the accredited practitioner (fire safety) witnessed a full system interface test.
Repairs that restore a measure to its original design generally do not need approval. An upgrade, modification or alteration can need a construction certificate or complying development certificate, or a change to the fire safety schedule. Heritage buildings and buildings under fire safety orders may need council notification or consent even for some repairs. If unsure, ask the council early.

Non-critical defect

Building Commission NSW recommends owners plan to rectify non-critical defects, because they can become critical over time. The NSW legislation does not require non-critical defects to be resolved immediately.

Non-conformance

Owners should consider how to resolve each one, case by case, with a suitably qualified person. It may not always be possible. In an older building, for example, the original design documents may be unavailable.

None of the official sources above sets a fixed rectification deadline for non-critical defects or non-conformances. Owners are expected to act in a timely way, guided by how serious the defect is.

Examples by measure

The examples marked "NSW guidance" come from Building Commission NSW material. The one marked "Illustration" simply applies the definition. Always classify against the standard's criteria and the building's design.

Measure	Finding	Class	Basis
Fire hydrant system	During the hydrostatic test, pressure drops rapidly (for example to 0 kPa or to town mains pressure) and the system will not hold pressure.	Critical	NSW guidance (good practice guide, Appendix D)
Fire hydrant system	During the hydrostatic test, pressure falls steadily but the make-up water used is more than the allowance.	Non-critical	NSW guidance (good practice guide, Appendix D)
Fire detection and alarm	After a lightning strike, the fire indicator panel cannot be reset or repaired, leaving the systems it controls inoperative.	Critical	NSW guidance (good practice guide, Appendix G, case study 1)
Fire pumpset	The pumpset fails catastrophically during its annual load test.	Critical	NSW guidance (good practice guide, Appendix G "Managing critical defects", case study 3)
Sprinkler, hydrant or pumpset systems	Baseline flow and pressure data from the original design is not available.	Non-critical or Non-conformance	NSW guidance (owner responsibilities page): generally not a critical defect
Any measure	A routine service activity is done outside its tolerance window.	Non-conformance	NSW guidance (good practice guide); AS 1851-2012 clause 1.11
Automatic sprinkler system	The main control valve is found shut, so no water reaches the installation.	Critical	Illustration The system cannot operate.

Defects and the annual fire safety statement

In NSW, AS 1851 servicing is separate from the annual fire safety statement (AFSS), but the accredited practitioner may use AS 1851 results to inform their assessment. If critical defects may delay the statement, Building Commission NSW advises owners to tell the council immediately and work with it on a solution. See How to prepare an AFSS in NSW.

How to record defects well

The NSW good practice guide notes that under AS 1851-2012, every repair goes into the system's records, with the fault, what was done to fix it and the date of service. It also says logbook entries should reference the AS 1851 section and the interval, and that a hard copy stays on site. A useful defect record has:

The building, the measure and its exact location (level, zone, riser, door number)
The AS 1851-2012 section and routine service interval during which it was found
The classification (critical, non-critical or non-conformance) and the reason for it
What you observed and any test readings, in plain words someone else can act on
Photos that show the location as well as the fault
Who you told, how, and when. For a critical defect, add the written confirmation within 24 hours and each reconfirmation when it is found again.
Any interim measures the owner put in place
The rectification: what was done, by whom and the date, plus any retest result
Whether the defect is still open on the yearly condition report

NSW owners must keep AS 1851 records for at least 7 years and make them available for inspection. Authorities such as the council or Fire and Rescue NSW can ask to see the logbooks.

Log defects where you find them

Fire Toad is an iPhone app for fire safety practitioners. During a guided site inspection you can log a critical or non-critical defect against the measure, with photos and notes, and track it until it's rectified. Defects carry through to your branded inspection report. The offline toolkit includes a defect classifier to help you think the classification through, though the call is still yours. Everything stays on your phone, with no account needed.

Get Fire Toad on the App Store

Free to download, with your first 3 reports included. Fire Toad Pro, a monthly or yearly subscription, covers reports after that.

Sources

Good practice guide for implementing AS 1851-2012 (January 2026 edition) · Building Commission NSW (defect classes table, p 11; reporting timeframes; Appendix D; Appendix G, case study 1)
Responsibilities of building owners under AS 1851-2012 · Building Commission NSW (inspection outcomes, records, relationship with the AFSS)
AS 1851-2012 Routine service of fire protection systems and equipment · Standards Australia catalogue (clauses 1.5, 1.16, 1.17)
Fire safety statements: frequently asked questions (PDF) · NSW Planning (essential and critical fire safety measures)
Environmental Planning and Assessment (Development Certification and Fire Safety) Regulation 2021 · NSW Legislation

This page is general guidance, not legal advice. It summarises AS 1851-2012 in plain language and does not reproduce it. Classify defects against your licensed copy of the standard, the building's fire safety schedule and design, and your own professional judgement. Fire Toad is not affiliated with Standards Australia or the NSW Government.