Phoenix Journal · Ductwork
Galley extraction systems work harder than almost any kitchen ashore, yet the ductwork is buried behind bulkheads and A-60 insulation where grease quietly builds. Proper marine and galley extraction cleaning strips that risk back to bare metal and keeps you on the right side of SOLAS and the MCA.
Marine and galley extraction
A galley is a commercial kitchen that never really stops, running in a confined steel hull where grease, salt air and heat all work against you at once.
On a vessel the extraction system is doing the same job as any shore-based canopy - drawing grease-laden vapour off the range, up through filters, along the ductwork and out through the fan - but the conditions are far less forgiving. Cooking often runs across long sea days with little downtime, so grease-laden vapour condenses and hardens on internal surfaces faster than most crews expect. Add salt-heavy air that accelerates corrosion, and you have a system that both fouls quickly and hides the evidence.
The bigger difference is where the ductwork goes. Marine galley ducts thread through accommodation, service spaces and control stations, so they are wrapped in fire-rated insulation and routed through tight, awkward runs rather than open ceiling voids. That layered, boxed-in construction protects the ship if a duct fire starts, but it also means grease sits out of sight behind bulkheads and cladding. You cannot judge a marine duct by glancing up at the canopy. The lower end of the run, the horizontal sections and the fan housing are where deposits gather, and those are exactly the parts a quick surface wipe never reaches.
Grease is the whole problem in one word. It is flammable, it accumulates in the hardest-to-see places, and once a fire takes hold inside a duct it travels along the run with a ready fuel supply on every internal surface. In a building you can evacuate outward; at sea the people, the escape routes and the fire are all inside the same steel envelope. That is why galley extraction cleaning is treated as a genuine fire-safety control rather than a housekeeping nicety.
The framework starts with SOLAS Chapter II-2, the international convention covering fire protection, detection and suppression. Regulation 9.7 deals specifically with exhaust ducts from galley ranges. Where those ducts pass through accommodation spaces, service spaces or control stations they must be insulated to A-60 class - built to hold back a serious fire for 60 minutes - and they must be fitted with features that make cleaning and containment possible.
Three of those features matter most for cleaning. First, a grease trap that is readily removable so grease can be caught and taken out rather than carried deep into the run. Second, a fire damper positioned at the lower end of the duct, at the junction with the range hood, that operates automatically and can be closed remotely to seal the duct in a fire. Third, inspection and cleaning hatches - one sited close to the exhaust fan, with further hatches down at the lower end of the duct where grease collects most heavily. There must also be a means of shutting off the exhaust fan. If any of those are painted over, seized or missing, the system is not compliant and it cannot be properly cleaned.
In UK waters the Maritime & Coastguard Agency (MCA) enforces these standards alongside IMO guidance, and surveyors and port state inspectors will expect to see that the galley extraction system is maintained and documented. For galleys on floating restaurants, moored vessels and dockside operations that also function as a workplace, the Regulatory Reform (Fire Safety) Order 2005 places a duty on the responsible person to manage fire risk - and the widely used benchmark for how clean a grease extract system should actually be is BESA's TR19 Grease specification. That standard sets out verified, measured post-clean cleanliness rather than a subjective "looks fine" judgement, which is why it is increasingly cited across marine work too.
The practical takeaway is simple. Compliance is not only about how the duct was built - it is about proving, on an ongoing basis, that grease is being kept under control and that the fire dampers and grease traps still work. That evidence is what protects you at survey, at insurance renewal and, most importantly, if there is ever an incident.
Frequency follows how hard the galley works, not the calendar alone. The established BESA usage bands are a sensible starting point for any grease extract system: heavy use of roughly 12 to 16 hours a day points to cleaning every three months, moderate use of 6 to 12 hours a day to every six months, and light use to around once a year. For busy marine galleys that cook through long operational days, a three to six month cycle is the realistic norm, and heavy continuous catering can justify tighter intervals.
The reason for the shorter cycles is the sheer rate of build-up. Grease can accumulate at several millimetres a month inside a working galley exhaust duct, concentrating at the lower end and in horizontal runs. It does not clear itself, and every millimetre is fuel. Industry data on land is stark - a large share of commercial kitchen fires originate in the extract system rather than at the hob - and there is no reason to think a hull is any more forgiving. Once a layer of hardened grease is heated past a few hundred degrees, it can ignite and carry flame along the entire duct.
Insurance is the other driver. Many marine and hospitality policies expect documented, standard-referenced cleaning, and a claim following a duct fire can be challenged if you cannot show the system was maintained. That makes each clean worth far more with paperwork attached to it. A proper visit should leave you with pre- and post-clean photographs, a record of what was accessed, and a formal certificate you can hand to a surveyor or underwriter. If you need that evidence formalised, an extraction cleaning compliance certificate turns the work into the audit trail an MCA review or port authority inspection will look for.
Between deep cleans, a few habits stretch the interval and reduce risk: keep baffle filters clean and correctly seated, empty the grease trap on schedule, watch for falling airflow or lingering odours as early warning signs, and never let inspection hatches get painted shut. None of that replaces a full strip-down, but it slows the rate at which grease reaches the parts you cannot see.
A proper clean follows the grease from the range to the fan, treating the whole system as one path rather than cleaning only what is easy to reach. It starts with a survey: opening every existing access hatch, checking where more access is needed, and identifying the horizontal runs and lower ducting where deposits concentrate. Where a long duct has no way in, additional access panels can be fitted so the interior can be cleaned and, just as importantly, inspected and verified afterwards.
From there the work moves systematically through the system. The canopy and plenum are degreased, baffle filters are removed and cleaned or soaked, and the removable grease trap is stripped out and dealt with. The internal duct surfaces are cleaned back towards bare metal using scrapers, brushes and safe degreasants suited to enclosed spaces, and the fan housing and impeller - a notorious grease trap in their own right - are cleaned so airflow is restored. The fire damper and the fan shut-off are checked to confirm they still operate, because a clean duct with a seized damper is only half safe. Confined-space and hot-work discipline runs through all of it, given where this work happens.
The clean is only finished when it is proven. Post-clean verification means photographing internal surfaces, recording measured cleanliness against a recognised standard such as TR19 Grease, and issuing documentation that ties the work to a date, a system and a result. That record is what converts a good day's cleaning into ongoing compliance - the difference between saying the duct is clean and being able to show it.
Grease trap emptied, damper tested, ductwork cleared · canopy, filters and fan restored · every stage logged. That is what keeps a galley safe on a long sea day and keeps your certification watertight when the surveyor comes aboard.
Questions
TR19 Grease is a land-based BESA specification rather than a maritime regulation, so it is not enforced at sea in the way SOLAS Chapter II-2 is. In practice, though, it is the clearest available benchmark for how clean a grease extract system should be, and it defines verified, measured cleanliness rather than a visual guess. Many operators and insurers use it as the reference point for marine galley cleaning, alongside MCA and IMO requirements, precisely because it produces defensible evidence.
You should receive pre- and post-clean photographs of the internal duct surfaces, a record of which sections and access points were cleaned, and a formal certificate stating the standard the work was measured against. This is the evidence an MCA surveyor, port state inspector or insurer will expect to see. Keeping those records in date order builds the audit trail that supports both compliance and any future claim.
Phoenix Duct Clean · by the numbers
Phoenix surveys and cleans kitchen and building ductwork to the TR19 standard - measured, cleaned and certificated, UK-wide.