Commercial Kitchens

Commercial kitchens prepare food in restaurants, hotels, hospitals, aged care, schools, staff canteens and food courts. They concentrate hazards in one room: open flames and hot oil under grease-laden exhaust hoods, gas, wet slippery floors, heavy electrical loads, cool rooms that people can be trapped in, and food safety requirements for every surface. Functionally the kitchen must cook safely, exhaust heat, smoke and grease, stay hygienic and pass inspection. Whether the operator or the building owner is responsible varies: in leased restaurants the tenant usually owns the fit-out but the building carries the exhaust riser, grease waste and gas supply.

What shortens fitness for purpose:

• Grease in hoods, ducts and fans when cleaning is missed.
• Water and chemicals attacking floors, junctions and substrates.
• Menu and equipment changes outgrowing the exhaust, suppression and power.
• Electrification of cooking replacing gas with heavier electrical loads.

Grease duct fires

Grease builds up in filters, hoods, ducts and exhaust fans. A flare-up ignites it, and fire travels along the duct, sometimes through floors to the roof. Infrequent cleaning, missing access panels and ducts without fire-rated enclosures turn kitchen fires into building fires.

Suppression mismatch

Wet chemical suppression is designed for a set appliance layout. When fryers and ranges are moved or added, nozzles no longer cover them; fusible links not replaced and gas interlocks bypassed stop the system working.

Make-up air and combustion

Exhaust without adequate make-up air puts the kitchen under negative pressure: doors slam, draughts pull smoke out of hoods, and gas appliances and flues backdraught, producing carbon monoxide.

Slips and floor failures

Wet, greasy floors cause slips. Floors without falls to drains hold water; failed floor junctions and wastes leak into substrates and floors below, rotting timber and corroding steel.

Cool room hazards

Cool room doors must open from inside; failed internal releases have trapped workers. Ice build-up damages panels, failed door seals waste energy and corrupt food safety, and refrigeration faults lose stock.

Hygiene and pests

Damaged wall linings, open joints, gaps around services and dead spaces behind equipment harbour pests and fail food safety inspections.

Equipment changes are the usual trigger: a new fryer bank, wok station or charcoal grill changes exhaust, suppression, power and gas loads all at once.

On site

• Grease on hood surfaces, filters and duct access panels; cleaning certificates and dates.
• Suppression nozzles against current appliance positions; service tags.
• Doors slamming or hard to open; smoke escaping hoods.
• Ponding water; cracked tiles and failed grout; floor wastes blocked.
• Cool room internal release present and working; ice on panels; damaged seals.
• Gaps around services; damaged linings; pest evidence.

In the records

• Exhaust cleaning certificates.
• Suppression system service records.
• Gas interlock tests.
• Food safety inspection reports.
• Trade waste and grease arrestor records.
• Leak history below the kitchen.

• Charcoal, wok or high-volume frying equipment added since the kitchen was designed.

Most kitchen findings trace to a mismatch between the kitchen as designed and the cooking it now does.

Findings are graded by what they demand: safety (can hurt someone now), failure (failed and damaging the building), condition (distress present and progressing), lifecycle (renewal due on age and exposure), deadline (a regulator or ordinance sets the date), check (investigate before sizing works) and nil (cosmetic or stable).

A building services engineer experienced in kitchen ventilation leads, with the suppression and gas contractors, a hydraulic engineer for floors and drainage, and the operator's food safety lead.

• Exhaust inspection: hoods, filters, ducts from hood to fan and the fan itself, with grease depth measured at access points and the duct route checked for access panels and fire-rated enclosure through floors.
• Airflow measurement of hood capture and make-up air, and observation at peak cooking.
• Suppression review: nozzle positions against the appliances now installed, service tags, link replacement dates, manual release, and gas and power shut-off on discharge.
• Gas safety check: appliances, connections, isolation, interlock to exhaust, and carbon monoxide levels with appliances running.
• Floor and drainage inspection with flood tests and checks below the kitchen for leaks.
• Cool room safety check: internal releases, alarms, lighting, panels and seals.
• Food safety review against recent inspection findings.

The report should list fire and life safety items first, then capacity against the current menu and equipment, and a refurbishment plan.

• Exhaust cleaning at a frequency matched to the cooking type (heavy frying and charcoal need far more frequent cleaning), with access panels added so the whole duct can be cleaned.
• Duct fire protection: fire-rated enclosures where ducts pass through other floors and spaces.
• Suppression redesigned to the current appliance layout, serviced and interlocked to gas and power.
• Make-up air balanced to exhaust so the kitchen is slightly negative but not starved.
• Floors: falls to drains, slip-resistant finishes, coved junctions and new membranes where leaks occur.
• Linings: impervious, cleanable surfaces with sealed penetrations to deny pests harbourage.
• Cool rooms: internal releases, alarms, seals, panels and refrigeration on cycle.
• Electrification planning: power capacity for induction and electric equipment where gas is being phased out.

Exhaust cleaning and suppression servicing recur, and are often the operator's cost. Exhaust, make-up air and duct fire protection upgrades are lump sums. Kitchen refurbishment is a lump sum including closure time, which in hotels and hospitals needs temporary kitchens. Floors and linings are priced by area. In leased premises, the lease decides who pays for base-building items such as the exhaust riser and grease waste.

Fire safety items are immediate; servicing is recurring compliance; refurbishment is lifecycle.

• Australia. AS 1668.1 and AS 1668.2 cover kitchen exhaust and fire requirements; AS 4674 covers the design and fit-out of food premises; the Food Standards Code sets premises requirements; gas installations follow AS/NZS 5601.1.
• United Kingdom. BESA DW/172 sets kitchen ventilation specification and TR19 Grease sets duct cleaning practice; food hygiene regulations apply; gas interlocks follow BS 6173.
• United States. NFPA 96 governs commercial cooking ventilation, including duct cleaning frequencies; UL 300 lists wet chemical suppression; the FDA Food Code and state health codes govern food premises.

Insurers in all three countries commonly require evidence of exhaust cleaning and suppression servicing, and may decline claims for kitchen fires without it.

Health authorities can close premises that fail food safety inspections.

• Exhaust and duct cleaning certificates.
• Suppression system service records.
• Gas compliance and interlock test records.
• Food safety inspection reports.
• Leak history below the kitchen.
• Lease allocation of kitchen responsibilities.

• Equipment schedule and layout as currently installed.
• Insurance requirements for kitchen fire protection.

• Pest control contract and reports.