Guide
How commercial ductwork cleaning is actually done
Updated
Knowing the sequence tells you which stages a low quote has skipped, and what a reasonable contractor should be doing on your premises overnight.
Stage by stage
- Survey. The system is traced from canopy to discharge, existing access points recorded, deposit levels checked and the areas that cannot currently be reached identified. This is what the quote should be built from.
- Access provision. Where there are not enough access panels, new ones are cut and fitted at intervals that allow the whole run to be reached and inspected. On a first clean this is often the largest single item.
- Isolation and protection. Electrical isolation of the fan, permits where needed, and sheeting to protect kitchen surfaces, equipment and floors.
- Filters and canopy. Filters removed and cleaned or replaced, the canopy plenum cleaned by hand, and the internal surfaces taken back to a clean condition.
- Ductwork. A combination of mechanical agitation, brushing or scraping and appropriate chemical treatment, worked section by section between access points.
- Fan and discharge. The extract fan cleaned, dismantled where necessary, and the discharge point dealt with. Frequently the dirtiest part of the job and the part most often skipped.
- Reassembly and test. Panels refitted and sealed, fan reinstated and run, extraction checked.
- Verification and report. Photographs at recorded locations before and after, deposit measurements taken, anything unreachable documented with the reason, and a recommended next clean date.
Safety items you are entitled to ask about
- Working at height arrangements for roof-level plant and high-level ductwork.
- Confined space assessment where anyone enters larger ductwork.
- Electrical isolation and lock-off of the extract fan before anyone works on it.
- Hot works controls if any cutting is involved in fitting access panels.
- Chemical safety data for whatever is being used in a food preparation area, and how surfaces are made food-safe afterwards.
- Public liability insurance and who is supervising the crew on site.
What the report should contain
- System description
- What was cleaned, described by section, so the report can be matched to the building.
- Before and after photographs
- At recorded, repeatable locations. Photographs from unnamed positions prove very little.
- Deposit measurements
- Measured readings rather than a visual opinion, taken at stated points.
- Areas not cleaned
- Every section that could not be reached, with the reason and what would be needed to reach it next time.
- Access panel record
- Where panels exist and where new ones were fitted, so the next contractor is not starting from scratch.
- Recommendation
- Next clean date with the reasoning, plus any remedial work identified.
- Who did it
- Company, operatives, date and time. A report nobody signed is not evidence.
Keep the report with your fire safety documentation, not just with your invoices. It is the fire risk assessment and the insurer that will ask for it, and neither of them will be looking in the accounts folder.