· Expert Exhaust Cleaning · Compliance · 5 min read
What a Compliant AS 1851 Cleaning Certificate Must Include
A valid AS 1851 cleaning certificate is more than a receipt — it records what was cleaned, measured and photographed, and it is what your insurer and auditor actually check.
A compliant AS 1851 cleaning certificate must record the system cleaned, the date and next-due date, the scope from canopy to fan and roof discharge, before-and-after evidence, measured grease-deposit thickness, and a named technician’s sign-off. It is the document your insurer, council and fire auditor accept as proof the exhaust system was serviced to the Australian Standard — not the invoice. Without every element present, a clean that was done properly can still fail an audit on paper.
What is an AS 1851 cleaning certificate?
An AS 1851 cleaning certificate is the formal record that a commercial kitchen exhaust system has been cleaned and inspected under AS 1851, the Australian Standard for the routine service of fire protection systems. Kitchen exhaust ductwork sits within that standard’s scope because grease build-up is the leading cause of commercial kitchen fires, so the clean is treated as fire-protection maintenance.
The certificate matters because it converts physical work into evidence. An insurer settling a fire claim, or a council officer during an audit, reads the certificate — not the state of the duct — so any missing field is a gap in your defence.
What must an AS 1851 cleaning certificate include?
A compliant certificate must identify the site, the system, the work performed, the condition found and the person accountable for it. The list below is the minimum an assessor expects to see, and each item exists to answer a specific question an auditor or insurer will ask.
| Certificate element | Why it must be there |
|---|---|
| Site address and system ID | Ties the record to one specific exhaust system, so it can not be mistaken for another kitchen |
| Date of service and next-due date | Proves frequency was met and flags the next clean before compliance lapses |
| Scope cleaned (canopy, filters, plenum, duct, fan, roof discharge) | Shows the full grease path was serviced, not just the visible canopy |
| Before-and-after photographs | Gives objective evidence grease was removed, the leading ignition fuel |
| Measured grease-deposit thickness | Quantifies risk against the standard rather than relying on opinion |
| Access panel locations and condition | Confirms every duct section was reachable and therefore actually cleaned |
| Areas not accessed, with reason | Discloses untreated risk honestly so it can be scheduled and rectified |
| Technician name, licence and signature | Makes a named, qualified person accountable for the work |
How does the certificate prove the whole grease path was cleaned?
It proves it by documenting each stage of the airflow — filters, canopy, plenum, ductwork, fan and roof discharge — as a separate item rather than a single “cleaned” tick. Grease coats the inside of the duct and fan housing, not only the canopy, so a certificate that lists the full path shows nothing was skipped.
This detail is why a genuine AS 1851 cleaning certificate reads like an inspection report. A single-canopy clean from ~$390 covers the canopy and filters, but a full canopy-and-duct service at $900–$2,500 must document the plenum, duct run and fan because those hidden sections carry the fire load.
How do grease readings and photos make a certificate defensible?
Measured grease thickness and dated photographs turn a subjective clean into checkable data, which is exactly what an insurer needs to accept a claim. A reading recorded in microns or millimetres before and after cleaning shows the deposit was reduced to a safe level, and the photos confirm it.
The reason this carries weight is fuel removal. Fire risk drops because grease — the primary ignition fuel in a duct fire — has been measurably removed, and the certificate is what evidences that reduction months later when memory and the duct’s condition have both moved on.
How often must the clean behind the certificate be done?
Most commercial kitchens need cleaning every 3–6 months, while charcoal, wok and high-volume frying operations need monthly filter cleaning and quarterly duct cleaning. The certificate’s next-due date must reflect the correct interval for your cooking type, because an out-of-date certificate is treated as no certificate.
Frequency is driven by grease load, not the calendar alone. Heavy frying deposits grease far faster, so a longer gap between cleans lets the leading cause of kitchen fires accumulate — which is why the standard scales frequency to output.
| Kitchen type | Filter clean | Duct clean | Why |
|---|---|---|---|
| Cafe / light cooking | Quarterly | 6-monthly | Low grease output, slower build-up |
| Standard restaurant | Monthly | 3–6 monthly | Moderate frying and grilling volume |
| Charcoal / wok / heavy frying | Monthly | Quarterly | High grease load and elevated fire risk |
How does AS 1851 relate to AS/NZS 1668.1?
AS 1851 governs the routine service and certification of the system, while AS/NZS 1668.1 governs how the mechanical ventilation was designed and built — including access-panel spacing and airflow. The certificate lives under AS 1851, but a system that breaches AS/NZS 1668.1 can not be fully cleaned or honestly certified.
The two connect at access. If the design left duct sections unreachable, the certificate must record them as not accessed — which is why the standards are read together. Our as-nzs-1668-1-vs-as-1851-difference explainer sets out where each one applies.
Why do insurers rely on the certificate?
Insurers rely on it because a compliant AS 1851 cleaning certificate is documented proof that a known fire hazard was controlled, and most commercial policies require that proof to pay a fire claim. A missing or incomplete certificate lets an insurer argue the maintenance condition was breached.
This is a settlement issue, not paperwork for its own sake. Cover holds because the grease that fuels kitchen fires was demonstrably managed on a schedule — see our guide to kitchen-exhaust-cleaning-insurance-requirements for exactly what most Sydney policies demand. Our compliance & safety cleaning service produces certificates built to survive an audit, from single canopies to multi-storey systems at $3,000+.
If your last certificate is missing grease readings, photos or a technician sign-off, it may not hold up when it matters. Get a same-day quote or call 0468 070 392, and we will clean, measure and certify your Sydney exhaust system so the document stands up to any insurer or auditor.
