No French text sets a flow rate for a commercial kitchen hood, nor a number of air changes per hour. The only enforceable figure is the one in article 64 of the county health regulation, expressed per meal served simultaneously, from 25 m³/h per meal below 150 covers down to 10 m³/h above 1,500. The labour code requires pollutants to be captured close to where they are released and sets only a floor, the fresh-air rates per occupant of article R.4222-6. In a dwelling everything changes in nature: the order of 24 March 1982 puts a figure on the kitchen directly, 75 to 135 m³/h according to the number of main rooms.
Understanding kitchen ventilation needs: commercial and residential
Air flow rates, air changes and extraction: what changes depending on use
In a dwelling, the duty attaches to an extract rate per room, fixed by the order. In catering, the duty attaches to an outcome, capturing pollutants where they arise, and the rate follows from what you have to remove. The first is verified with a flow hood against a table, the second is justified by a calculation note. Confusing the two leaves you with nothing to produce on inspection day.
The three sets of rules that must not be mixed
Three regimes coexist, each with its own unit, and that heterogeneity is what explains the permanent confusion on this subject.
| Situation | Applicable text | What it puts a figure on |
|---|---|---|
| Kitchen in a dwelling | Order of 24 March 1982, article 3 | Kitchen extract rate, 75 to 135 m³/h by number of main rooms |
| Catering kitchen, diners | Article 64 of the county health regulation | Fresh-air rate per meal served simultaneously, or per m² of cooking surface |
| Commercial kitchen, employed staff | Labour code, R.4222-6 and R.4222-11 | Fresh-air floor per occupant, sizing from pollutants and heat |
| Large kitchen in a public building | Order of 25 June 1980, GC articles | No ventilation figures at all, only materials, fire resistance, capture and maintenance |
The last line always surprises. Chapter X of the fire safety rules governs large kitchens, defined in article GC 1 as those where the total useful power of the cooking appliances exceeds 20 kW, yet it contains no flow rate, no air velocity and no air-change rate. It is a fire text: it requires rigid metal ducts, materials rated M0 or A2-s1 d0, grease-retaining elements, an EI 60 fire-resistant penetration, and for an open kitchen fans able to keep working for at least one hour with flue gases at 400 °C.
What article 64 of the county health regulation really says
The model health regulation is issued by circular and has no force in itself: it becomes enforceable county by county, adopted by prefectoral order. Two drafts of article 64.2 coexist today depending on the county, so open the local regulation before quoting a value. The more widespread draft ties the rate to the meal served simultaneously:
| Catering kitchen | Minimum fresh-air rate | Floor |
|---|---|---|
| Satellite servery | 15 m³/h per meal | not applicable |
| Fewer than 150 meals | 25 m³/h per meal | not applicable |
| 151 to 500 meals | 20 m³/h per meal | 3,750 m³/h |
| 501 to 1,500 meals | 15 m³/h per meal | 10,000 m³/h |
| More than 1,500 meals | 10 m³/h per meal | 22,500 m³/h |
The older draft expresses the same requirement as 300 litres per second per m² of cooking surface. Two provisions accompany the table and weigh heavily on the pricing. Pollutants must be captured close to where they are released. And where a capture system cannot be installed, the rates needed to ventilate the kitchen must be doubled. A design without a hood therefore costs twice as much to ventilate, which is the strongest argument to put in front of a client who wants to economise on capture.
Regulations and safety: your obligations in 2026 depending on kitchen type
Commercial kitchen: fire safety, hygiene and inspections (points to check)
In premises open to the public, article GC 4 requires an emergency cut-off per type of energy, with the control inside the room and close to either the entrance or the cooking block, and one counter-intuitive rule worth remembering: the electrical cut-off must not switch off either the lighting or the smoke extraction. On hygiene, Regulation (EC) 852/2004 merely requires adequate and sufficient ventilation, with no figure at all, which puts the burden of proof back on your calculation note.
- The rate justified in writing, per meal or per m² of cooking surface, citing the county regulation.
- Capture close to the source, or the rate doubled and that decision written down.
- Filters and ducts accessible, inspection hatches clear and labelled.
Residential kitchen: ventilation requirements and good installation practices
In a dwelling, the kitchen is a service room within the meaning of the order, with its mandatory air outlet and its extract rate. One rule is regularly broken in blocks of flats, that of article 14: no individual mechanical device, powered cooker hood included, may be connected to a communal air outlet installation, whether mechanical or passive. That is rework at your expense, and it is checked before quoting. Connecting a hood remains possible in configurations designed for it, which our guide on hood and mechanical ventilation compatibility sets out.
Mandatory maintenance and traceability: who does what, and how often
Article GC 21 sets two numeric frequencies, the only ones in the chapter: filters are cleaned or replaced as often as necessary and at least once a week, and extract ducts are swept at least once a year. For specialised modules and containers, article GC 18 additionally requires the extract duct to be cleaned before each installation and at least every six months. A maintenance booklet is annexed to the safety register. Write those intervals into the contract rather than leaving them to the operator's judgement.
Equipment and sizing: choosing the right ventilation for the kitchen
Hood, extraction unit, ductwork: design differences between commercial and home
In a dwelling, the hood is an intermittent addition sitting alongside a ventilation system that carries the permanent duty. In catering, the hood is the capture device that governs the whole regulatory rate, since its absence doubles it. The consequence for the ductwork is direct: rigid metal ducts required by article GC 10, materials rated M0 or A2-s1 d0, grease-retaining elements that are easy to clean and replace. Flexible aluminium has no place in the second case.
Fresh air supply and balancing: avoiding negative pressure, backdraught and discomfort
Extracting without making up puts the room under negative pressure, and article GC 10 addresses it head on: the air supply may only be mechanical if the extraction is mechanical too, and for an open kitchen article GC 11 requires mechanical extraction with the supply interlocked to it. On site, that means the supply grille is sized at the same time as the hood, not afterwards. Uncompensated negative pressure shows immediately: doors that are hard to open, odours backing up from drains, and on a gas installation a risk of poor draught.
Filtration and grease treatment: trays, filters, separators (commercial cases)
Grease load is what physically separates the two worlds. Deep fryers, griddles and grills produce aerosols that settle inside the duct and become fuel. Hence the logic of the text: capture as close as possible, retain in removable elements, keep the rest reachable for cleaning. Plan the collection trays and the access hatches at the routing stage, because a duct that cannot be cleaned is a duct that will one day be replaced, and it is the insurer who will ask the question.
Installation on site: points of attention for lasting ventilation
Duct layout and pressure losses: limits, bends, lengths
The ductwork calls the shots. Limit unnecessary lengths, narrowings and crushed flexible ducts. Add too many bends and you accumulate pressure losses that reduce the rates you have committed to holding. Favour large-radius bends, keep consistent diameters, and fit the grilles according to manufacturer instructions. To go further, see this guide on mechanical ventilation ductwork.
Acoustic treatment and vibration: reducing nuisances in operation
Treat both the unit and the ductwork. Suspend the unit on anti-vibration mounts, avoid any direct contact with partitions, and insert a flexible sleeve. A silencer on the main duct and insulation of ducts near sensitive rooms cut noise and vibration without restricting flow. In premises open to the public, check that the sleeve chosen still meets the material requirements of article GC 10. The attenuation options are chosen before installation, not after the complaint.
Airtightness, materials and maintenance access: plan before closing up
Before closing up, check the airtightness of the joints and tap-offs, with materials compatible with any condensation. Leave maintenance access to filters, grilles and hatches, with enough room to dismantle them. That is effectively a duty once the text requires weekly filter cleaning and annual sweeping: an unreachable hatch makes maintenance compliance impossible to hold, and it is your installation that will be questioned.
Costs, maintenance and client feedback: justifying ventilation without nasty surprises
Installation budget: what weighs most in a commercial kitchen
The price depends mainly on the ductwork, its length and its penetrations, with the premium for rigid metal ducts and fire-resistance ratings. Add the hood, grease filters, acoustics and the make-up air supply. Against a cheaper bid, the numeric argument is in the text: without capture, the rate to be delivered doubles, and with it the size of the unit, the duct cross-section and the running cost.
Electrical consumption and operation: speed controller, control, schedules
Consumption comes from the fan running for long periods. A speed controller and control by schedule or sensor let you match flow to service. One caveat to put in writing: modulation cannot drop below the rate adopted under article 64 during service, or the calculation note loses its value. Control is justified outside service hours, not during the rush.
Maintenance contract and cleaning: anticipating breakdowns and odours
Without regular cleaning, grease builds up and the duct becomes a fire risk. Set the contract against the intervals in the text, filters at least weekly, sweeping annually, plus the six-monthly duct cleaning for specialised modules. Date every visit, photograph the cleaned sections, and annex the booklet to the safety register. That is what covers you, and what reassures your client's insurer. On the residential side, where flow rates are set room by room rather than by cooking appliance, surveying the existing system and sizing it follow a different logic.
