Short answer: Fryers, griddles and chargrills do not create the same exhaust. Fryers produce grease aerosol and odour; griddles vary with food and temperature; chargrills can generate heavy smoke, fine particles and strong odour. Filtration must be based on the appliance schedule, fuel, menu, peak load and operating hours.
Two kitchens with the same canopy length can need very different treatment. Equipment duty categories help ventilation design, but the filtration supplier also needs real cooking information. A nominal “restaurant system” can be under-specified if the menu shifts from light reheating to burgers, steaks or continuous frying.
Important: This guide explains design questions; it is not a product selection, planning approval or performance guarantee. A competent designer should assess the actual kitchen, air system, discharge and maintenance conditions.
Frying duty
Open frying releases heat, vapour, oil aerosol and characteristic odour. Oil condition, temperature, product moisture and production rate change the load. Effective canopy capture and grease separation are fundamental; fine particulate and gaseous treatment depend on site risk.
- Number, width and energy input of fryers.
- Continuous versus batch use.
- Oil management and cleaning practices.
- Peak production and opening hours.
Griddles and planchas
A griddle cooking lean food at moderate load is different from a high-temperature burger or bacon operation. Fat drips and surface residues create smoke and odour. The designer should use the intended menu and not treat every flat-top appliance as one emissions category.
- Food fat content and marinades.
- Surface temperature and production rate.
- Scraping/cleaning regime.
- Position under the canopy and side draughts.
Chargrills
Chargrills can create strong visible smoke and fine particles, particularly where fats drip onto hot surfaces or solid fuel is used. High particulate and odour risk may support ESP and gaseous treatment, but fire, spark, soot and solid-fuel requirements need separate specialist consideration.
- Gas, electric or solid-fuel heat source.
- Cooking surface and fuel quantity.
- Smoke peak during loading and flare-ups.
- Fire strategy and cleaning access.
What the observation may be telling you
| Observation | What it may mean | Correct next step |
|---|---|---|
| Light griddle use | Moderate variable grease/odour | Confirm duty rather than assume low risk |
| Continuous frying | High grease aerosol and odour | Strong grease separation and maintained treatment |
| Gas chargrill | Smoke, fine particles and odour | Consider ESP plus gaseous treatment |
| Solid-fuel chargrill | Smoke, soot, sparks and CO risks | Use specialist solid-fuel design |
| Menu changed after opening | Original treatment basis may no longer apply | Reassess airflow, filters and planning conditions |
A practical odour-control workflow
Odour control is a chain of source control, capture, particulate removal, gaseous treatment, dispersion and maintenance. The weakest link can dominate what a neighbour experiences. Use a documented process so the proposed equipment relates to the actual kitchen and receptor risk.
- Characterise the cooking. Record menu, appliances, fuel, peak production, operating hours and likely changes. Separate grease and smoke problems from gaseous odour, because one treatment stage rarely controls every fraction equally.
- Assess the site risk. Map the duct route, proposed discharge and nearby windows, terraces, air intakes and residences. Consider frequency and duration of exposure as well as distance. Capture planning or environmental-health requirements verbatim.
- Design the complete sequence. Protect carbon or oxidation stages with suitable grease and particle removal. State airflow, contact or exposure basis, temperature and humidity limits, pressure loss, alarms, interlocks and safe access.
- Operate to evidence. Commission the complete system and retain baseline readings. Log cell cleaning, lamp hours, carbon changes, fan checks and complaints. If an odour returns, the timeline helps separate a maintenance failure from an under-designed system or a changed menu.
Keep a useful record: The handover file should identify media type and mass, cell configuration, lamp details, design airflow, clean pressure readings, replacement criteria, safe isolation and the route for removing contaminated components. A vague instruction to “service annually” is not a useful odour-management plan.
Project or service checks
- List every appliance model and fuel.
- Describe menu and peak simultaneous operation.
- Record opening hours and covers/production.
- Identify grease, smoke and gaseous treatment separately.
- Check canopy geometry and replacement air.
- Plan cleaning frequency for the actual load.
- Review the design when the menu or equipment changes.
Turn the agreed checks into named deliverables. Each item should have an owner, due date and acceptance method. Where a measurement is required, record the value, unit, instrument or source, operating condition and result. This makes the information usable at handover and during a later investigation.
Common mistakes to avoid
- Specifying from kitchen floor area only.
- Calling all electric cooking low emission.
- Ignoring food fat and cooking temperature.
- Using filtration selected for a former menu.
- Treating solid fuel as an ordinary chargrill.
Avoid closing the issue on appearance alone. A new filter, reset controller or revised drawing may change the symptom without resolving the underlying duty, utility, access or maintenance problem. Confirm the completed work under a representative operating condition and keep the evidence with the asset or ventilation record.
Frequently asked questions
Does an electric fryer need less filtration than gas?
Fuel affects combustion products, but the food and oil still create grease and odour. Filtration is not removed simply because the appliance is electric.
Which appliance creates the most odour?
It depends on food, temperature, fuel, volume and operation. Chargrilling and some frying/spice processes can be demanding, but the site assessment decides.
Can filters be reduced if cooking is occasional?
Operating pattern is relevant, but any design reduction must be justified and should consider peak rather than average use.
Related Kitchen Install Guide reading
- Commercial Kitchen Equipment Duty Categories
- Commercial Kitchen Odour-Control Systems Guide
- What Is an EMAQ+ Kitchen Odour Assessment?
Plan the whole commercial kitchen, not one isolated component
Use the Commercial Kitchen Install Guide to coordinate extraction, equipment, utilities, drainage, safety, access and handover before work reaches site.
Sources and further guidance
- BESA: DW/172 Specification for Kitchen Ventilation Systems
- HSE: Ventilation of kitchens and catering establishments
- EMAQ+: Control of Odour and Noise from Commercial Kitchen Exhaust Systems
- Extechnology: ESP, carbon, ozone and kitchen extract treatment
Last reviewed: 14 August 2026. This article provides general commercial-kitchen design information. It does not replace a site-specific ventilation design, manufacturer instructions, risk assessment, planning conditions or advice from a competent specialist.