Kitchen ventilation is the part of a cleaning programme that gets delegated most easily and audited most slowly. Nobody doubts that the canopy above the line needs a wipe at the end of the night; what nobody can answer on demand is how much water the deeper work — the baffles, the fan housing, the upper duct run — actually consumes, and whether that water can get in and out of a working kitchen at all. Until those two numbers are on paper, a ventilation cleaning schedule is a wish.
Start with the water already on the sheet
Most kitchens clean ventilation with the nearest available tool — a hose, a pressure washer, a bucket and a scrub. The water that goes with those tools rarely gets measured, so record it before changing anything. Two entries are enough to start: how much water the current method uses per session, and where the run-off goes once it leaves the hood, carrying emulsified grease with it. In a basement kitchen or a food court unit, the second entry usually has no honest answer, and that gap decides the method before any machine is specified.
Break the job into components and give each its own figure
"Clean the extraction system" cannot be costed. Split it into the surfaces a crew can reach and the ones they cannot: the outer canopy panels, the grease filters and their racks, the internal faces of the hood, the plenum, the fan housing and impeller, the accessible duct length, and the exterior terminal. For each one, note three things — access time, how the deposit is loosened, and how much water that loosening consumes. Filters soak in a tank of hot detergent, and that volume is fixed and reusable. An internal hood face washed down with a lance is open-ended, and the run-off has to be caught, channelled and bailed out by hand.
| Component | How water is used | What to record |
|---|---|---|
| Grease filters and racks | Soak tank or sink, batch work off the line | Tank volume, how often the bath is changed |
| Canopy interior and plenum | Lance or machine, run-off falls into a catch tray | Machine supply rate, tray capacity, disposal route |
| Fan housing and impeller | Isolated, opened, wiped and sprayed | Drying time before restart |
| Accessible duct length | Access panel by access panel | Panel count, water per panel, residual moisture check |
| Canopy exterior and tiles | Wipe or low-volume steam over hot surfaces nearby | Whether the line has to close during the task |
Once the table is filled, the difference between methods becomes visible rather than argued about. The soak-tank line has a fixed figure. The lance line does not, and that is usually where a kitchen's water problem sits.
Use the equipment's own duty figures instead of estimating
Machine specification gives you the boundary values the table needs, and they should be read as engineering data rather than marketing text. On a plumbed unit such as the Fixed Steam Cleaning Machine PowerDe HW02, the published figures — an 80-litre SUS304 tank, 220 V supply and a tap-water inlet — say two useful things: the water carried to the job is limited by tank volume, and the supply hose is a domestic fitting rather than a demand that the site plumbing has to absorb. Compare that against a hose or pressure washer whose flow runs continuously while the trigger is open, with no fixed upper bound, and the comparison writes itself.
The same page lists 160 °C steam temperature and 0.8 MPa vapour pressure. Treat those as the two variables that change the labour calculation on polymerised grease. A cold lance lifts fresh oil; a varnished film that has been baked onto a baffle repeatedly does not respond to cold water at all, however long the crew sprays at it. Heat softens the layer first, and pressure then moves what has already been released. The practical reading for a water audit is that the deposit's removal time, not the flow rate, is what determines how much water ends on the floor.
The dry-steam and wet-steam switch matters more in a duct than on a floor. A dry and wet steam cleaner lets the crew put heat into the deposit with the drier mode, then use the wetter mode as a short rinse once the film has let go. Inside a hood and duct run that choice is not cosmetic: residual water there has nowhere to go, it mixes with the remaining grease and the mixture drips back out of the joints the crew just opened. Less water on the surface means a shorter drying time before the extraction fan is certified to run again, which in a restaurant that cannot close at lunch is the whole point.
Count the run-off as part of the cost
Water that leaves a hood is greasy water, and the disposal route has to be written down before the method is chosen. Greasy run-off belongs in the site's waste route through the grease interceptor. It does not belong in a prep-area sink, a floor drain, or a surface channel that feeds the foul drain directly. Add a line to the assessment for who checks the interceptor and how often it is emptied, because an interceptor that is already full turns a compliant clean into a flood and a compliance problem.
Where the kitchen sits below grade, or where the only water point is a long hose run across a dining area, the constraint should decide the equipment instead of the catalogue deciding it. That is the point at which a fixed unit beside the wash point and a mobile unit in the Cleaning Equipment Series stop being a preference and become a decision made from the site survey.
Run one measured trial before you set the frequency
Pick the worst extraction run in the building and clean it with the method you are considering, with two people and a sheet. Record the elapsed time per component, the water drawn from the tank or the hose, the volume of run-off collected, and the time until the fan housing is dry enough to restart. Also record what the crew had to stop and re-do. A trial that produces four numbers beats a supplier's datasheet for setting your own frequency, because it tells you which component drives the cost — and in most kitchens that turns out to be access and drying time, not the cleaning itself.
Then put acceptance criteria in the record that a duty manager can check in seconds: no visible oil film on the filter faces after the soak and rinse, no standing water in the plenum, the impeller free to turn with no residue on the blades, joints and panel seams dry to the touch, and the floor below the hood dry within a metre of the line. Deep grease in an extract system is a fire issue as much as a hygiene one, so the record of what was cleaned, when, and to what standard carries as much weight as the clean itself when an assessor asks.
The safety steps do not belong in a footnote. Isolate the fan and lock it off before anyone reaches the impeller; confirm the line and the hood surfaces have cooled before steam goes near them, because steam onto a hot metal surface produces an immediate flash of vapour that scalds the operator; cover dry goods and open chemicals in the room before any steam is generated, since vapour travels and settles; and never spray directly at motors, terminal enclosures, or the control wiring on the fan housing — those get wiped around, not washed.
Turn the figures into a schedule the second shift can follow
With measured durations and water volumes against each component, set frequencies by deposit rather than by habit. Filters on a busy fryer line will not sit on the same interval as a canopy serving a steamer. State the method per component — soak, steam with dwell, wipe — so a crew that was not in the trial repeats the same result, and state the working distance, the dwell on the deposit and the number of passes for the two worst surfaces. Three details like those are the difference between a method that survives a change of shift and one that only works when the same person does it.
Review the record on a fixed date against the signed sheets and a walk of the run. If a task keeps slipping, the interval or the allotted duration is wrong and the fix belongs in the document, not in a reminder at the morning briefing. If a baffle still needs heavy scrubbing after the scheduled method, that is a finding about the method.
Where the duct run is long, the access panels are few, or the kitchen shares a riser with other units, standard configurations will not fit the job. Shenzhen PowerDe Automation Precision Equipment publishes parameters for each machine in its cleaning range, and customized steam cleaning equipment can be specified against your extraction layout and duty cycle. Send the component list from your assessment and photographs of the worst deposits through the contact page, and ask for a method and configuration matched to the kitchen rather than a catalogue page.
