Commercial Kitchen Deep Cleaning Guide — Exhaust, Hood & Grease Trap
Key Points
- Commercial kitchen deep cleaning covers four distinct systems: the exhaust system (ductwork, plenum, fan), the extraction hood, the cooking equipment, and the grease trap — each requires separate procedures and different frequencies.
- Exhaust system deep cleaning must comply with AS 1851 — the Australian Standard for fire protection systems maintenance. Melbourne councils, insurers, and building owners require an AS 1851 compliance certificate after each clean.
- The recommended frequency for most commercial kitchen exhaust deep cleaning is quarterly — every 3 months. High-heat operations (charcoal, wood-fired, wok) may require monthly cleaning due to higher grease accumulation rates.
- Grease trap pumping is separate from exhaust system cleaning and is typically required monthly to quarterly depending on kitchen volume — it must be performed by a licensed liquid waste contractor.
- Deep cleaning is distinct from daily kitchen cleaning — it requires specialist equipment, high-temperature chemicals, and access to areas not reachable during routine nightly cleaning.
Understanding the Four Deep Cleaning Systems in a Commercial Kitchen
When restaurant and cafe operators talk about "deep cleaning the kitchen," they often mean different things. A complete commercial kitchen deep cleaning program covers four distinct systems — each with its own standards, frequency requirements, and consequences for non-compliance. Understanding these four systems is the foundation of an effective deep cleaning program.
1. Exhaust System
The ductwork, plenum chamber, and extraction fan above the cooking equipment. Grease-laden vapour from cooking travels through this system and deposits on internal surfaces. AS 1851 deep cleaning required — quarterly for most kitchens.
2. Extraction Hood
The canopy and filters directly above cooking equipment that capture grease vapour before it enters the ductwork. Filters should be cleaned weekly; the hood interior (canopy surfaces, grease channels) requires deep cleaning as part of the quarterly exhaust program.
3. Cooking Equipment
Ovens, fryers, grills, griddles, and ranges require periodic deep cleaning beyond daily degreasing — specifically the interior oven cavities, under-equipment floor areas, and internal fryer components. Weekly to monthly depending on usage.
4. Grease Trap
The underground or in-floor interceptor that captures fats, oils, and grease from dishwashing and cooking waste before they enter the sewerage system. Must be pumped out by a licensed liquid waste contractor — monthly to quarterly.
AS 1851 Exhaust System Deep Cleaning — What It Involves
AS 1851 is the Australian Standard for the maintenance of fire protection systems and equipment — and commercial kitchen exhaust systems fall within its scope because accumulated kitchen grease is a direct fire risk. A grease-laden exhaust duct that ignites during cooking is one of the leading causes of commercial kitchen fires in Australia.
An AS 1851-compliant exhaust system deep clean involves accessing and cleaning the complete exhaust pathway — from the extraction hood and canopy through the ductwork, plenum chamber, and exhaust fan. This is not the same as cleaning rangehood filters, which is a weekly task that addresses the removable filter panels only.
What AS 1851 Exhaust Cleaning Covers
Important: AS 1851 exhaust system cleaning must be performed by a trained and qualified technician — not general kitchen staff or a standard cleaning contractor without specialist exhaust cleaning training. The AS 1851 certificate is only valid when issued by a qualified technician who has performed the work to the standard. An uncertified certificate has no legal standing for council or insurer purposes.
How Often Does a Commercial Kitchen Need Exhaust Deep Cleaning?
The recommended frequency varies based on the type of cooking performed in the kitchen. AS 1851 provides guidance on inspection and cleaning frequency based on cooking type and volume.
| Kitchen Type | Recommended Frequency | Rationale |
|---|---|---|
| Charcoal grill, wood-fired oven, open flame | Monthly | Carbon and grease accumulate at rates 3–4× standard gas cooking |
| High-volume wok cooking, deep fryer-heavy | Monthly to quarterly | Wok cooking and deep frying produce high grease vapour volumes |
| Standard commercial kitchen — medium volume | Quarterly | AS 1851 recommended minimum for most commercial kitchens |
| Low-volume cooking, primarily assembly/cold prep | Bi-annual | Low grease vapour generation — 6-monthly may be appropriate |
| Cafes with limited cooking (toast, sandwiches only) | Annual minimum | Minimal grease vapour — annual often sufficient if rangehood filters cleaned weekly |
Tip: When in doubt, default to quarterly. The cost of a quarterly exhaust clean is insignificant compared to the cost of a kitchen fire, an insurance claim rejection for non-compliance, or a council improvement notice. Golden Star provides quarterly exhaust programs on a pre-booked annual schedule — you don't need to remember to book each clean. Call 0484 042 336 to arrange.
Grease Trap Cleaning — What Melbourne Restaurants Need to Know
A grease trap (also called a grease interceptor) is a plumbing device installed under or adjacent to a commercial kitchen that captures fats, oils, and grease before they enter Melbourne Water's sewerage system. Under the Trade Waste Agreement that commercial kitchens in Melbourne must hold with Melbourne Water, grease traps must be maintained in working order and pumped out regularly.
Grease trap pumping is not the same as kitchen cleaning and cannot be performed by a standard cleaning contractor. It must be performed by a licensed liquid waste contractor who is registered to handle and dispose of grease trap waste. The waste is classified as trade waste and must be transported and disposed of in accordance with EPA Victoria requirements.
Grease Trap Maintenance Requirements for Melbourne Kitchens
| Requirement | Detail |
|---|---|
| Pump-out frequency | Monthly to quarterly depending on kitchen volume — your Trade Waste Agreement specifies the required frequency for your premises |
| Who can pump out | Licensed liquid waste contractor only — not general cleaning staff or plumbers without liquid waste licence |
| Records required | Pump-out records must be retained and available for Melbourne Water and council inspection |
| Overflow consequences | A blocked or overflowing grease trap can result in sewage surcharge from Melbourne Water, council fines, and potential Food Act compliance notices |
| Interior inspection | In addition to pumping, the trap interior should be inspected for damage, baffle condition, and inlet/outlet integrity at each service |
Commercial Cooking Equipment Deep Cleaning
Beyond the exhaust system and grease trap, the cooking equipment itself requires periodic deep cleaning that goes beyond nightly degreasing. These are the tasks that daily kitchen staff typically cannot complete because they require moving or partially disassembling equipment, using high-concentration commercial degreasers, and extended dwell and scrub times that aren't feasible during a normal kitchen close.
| Equipment | Deep Clean Task | Frequency |
|---|---|---|
| Oven | Full interior deep clean — racks, door seals, glass, cavity walls; high-temp oven degreaser with extended dwell time | Weekly |
| Deep fryer | Full boil-out — drain oil, fill with water and fryer cleaner, bring to temperature, drain and rinse; clean fryer walls, element, and basket | Weekly |
| Grill & griddle | Carbonised grease removal from cooking surface, underneath grill plates, and drip pans using specific grill degreaser | Weekly |
| Under all equipment | Move fryers, ovens, and ranges; clean floor, wall behind, and base of equipment | Weekly |
| Coolroom interior | Remove all items; wash and sanitise walls, ceiling, shelving, door seals, and floor; check drain | Weekly to monthly |
| Dry store shelving | Remove all items; wipe and sanitise all shelving surfaces; check for pest activity | Monthly |
Action Steps — Setting Up Your Deep Cleaning Program
1. Book quarterly AS 1851 exhaust cleaning now — for the full year. Don't manage this as a one-off booking. Book all four quarterly cleans at the start of the year with a certified cleaning provider. Golden Star issues AS 1851 certificates accepted by all Melbourne councils. Call 0484 042 336 to set up your annual exhaust program.
2. Confirm your grease trap pump-out schedule with your Trade Waste Agreement. Check your Melbourne Water Trade Waste Agreement for the required pump-out frequency for your premises. If you don't know where your agreement is or what frequency it specifies, contact Melbourne Water to confirm — non-compliance with grease trap requirements can result in surcharges and notices.
3. Add weekly equipment deep cleaning to your professional cleaning program. Weekly tasks — oven interior, under-equipment, coolroom — are most reliably handled by a professional cleaning team with the right equipment and chemicals. Add these to a weekly professional cleaning program rather than relying on end-of-service kitchen staff who don't have the time, products, or training for deep equipment cleaning after a full service.
4. Keep all compliance certificates on file in the kitchen. AS 1851 exhaust certificates, grease trap service records, and council food safety inspection notes should all be stored in a single folder in the kitchen — not in a filing cabinet in the office. When an inspector arrives, you need to be able to produce these records immediately.
Frequently Asked Questions
AS 1851 is the Australian Standard for the maintenance of fire protection systems and equipment — published by Standards Australia. Commercial kitchen exhaust systems are included within its scope because accumulated kitchen grease in exhaust ductwork and plenums is a direct fire risk. A grease-laden exhaust duct that ignites during cooking can spread fire rapidly through the entire ductwork system and into the building structure. Melbourne councils, building owners, and insurers require an AS 1851 compliance certificate after each exhaust deep clean as evidence that the fire risk has been managed. Operating without current certification can void your fire insurance policy and create council compliance issues under the Building Act 1993 (VIC).
No. AS 1851 exhaust cleaning must be performed by a trained and qualified technician. The standard requires specific knowledge of exhaust system configurations, safe access procedures for ductwork, appropriate chemical selection and application for grease removal, and post-clean inspection to confirm the system meets AS 1851 grease accumulation limits. A certificate issued without qualified work being performed has no legal standing. Kitchen staff cleaning the rangehood filters is a weekly maintenance task — it is not the same as an AS 1851 exhaust system deep clean and does not satisfy the AS 1851 requirement.
Your Melbourne Water Trade Waste Agreement specifies the required pump-out frequency for your premises — this is the contractual minimum. Operationally, a grease trap needs pumping when the accumulated grease and solids layer exceeds 25% of the trap's capacity (a common rule of thumb). Warning signs that a grease trap needs immediate attention include slow drain flow in kitchen sinks, grease odour from floor drains, and visible grease in kitchen floor drains. Do not wait for these signs — pump on schedule regardless. Contact a licensed liquid waste contractor to arrange regular scheduled pump-outs on the same cycle as your exhaust cleaning.
Commercial kitchen deep cleaning uses high-concentration alkaline degreasers — typically between pH 12 and pH 14 — that are significantly more aggressive than the pH-neutral cleaners suitable for daily kitchen cleaning. For exhaust systems, these products are applied at full concentration and allowed extended dwell times (15–30 minutes) to break down polymerised (baked-on) grease before agitation and removal. For cooking equipment, specific oven degreasers that are safe for the surface type are used. All products used in food zones must be APVMA-registered food-grade products. The high-concentration chemicals used in deep cleaning are not appropriate for daily kitchen use and require appropriate PPE and training to use safely.
Related Guides
Need AS 1851 exhaust deep cleaning for your Melbourne restaurant or cafe? Golden Star provides certified quarterly exhaust programs across all Melbourne councils — certificates issued same day.
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