The pipe above the range is the part nobody wrote down. Hoods, stoves and prep counters all have a task line on the schedule; the exhaust duct, the riser behind the wall and the fan housing usually appear in the fire risk assessment and nowhere else. On a steam job those surfaces behave differently from a wall or a floor, and the reason is geometry. Whether a steam wand clears a kitchen pipe exterior in ten minutes or forty depends on five site conditions you can check before you buy the machine.
What is actually on the outside of the pipe
Grease that has travelled a year in a working kitchen is not cooking oil. Aerosol from the fryer and the grill settles on the duct, then bakes on whenever the extract is running hot, and it polymerises into a hard varnish with a carbon fraction in it. Fresh splatter wipes off with detergent and warm water. Polymerised film does not, because it is a solid bonded to the metal, and the bond survives cold solvents and scrubbing.
That is why heat does the work. A machine that delivers dry steam — high temperature with little free water — softens the film so pressure can lift it. The PowerDe HW02 steam cleaner is specified at 160° steam temperature and 0.8 MPa vapour pressure with a 6 kW heater, which is the class of duty needed for that film. A domestic steam mop running at low pressure will warm the surface and stop there. The first site condition is therefore simple: how thick and how old the coating on your duct is, because it sets the temperature and pressure you need and rules out weak equipment before you look at anything else.
Reach, and whether the work happens off the floor
Most kitchen pipework runs two to four metres above the line, along the ceiling zone, with elbows and a damper in the run. A crew working from a ladder with one hand on the wand and the other on the rail is slow and unsafe, and slow means the job gets shortened. Decide where the crew will stand: tower scaffold, podium steps, a mobile elevating work platform, or a floor-level wand with an extension lance.
This decides how far the machine has to sit from the work. Hose length and lance length are the two numbers that matter, and the HW02 specification sheet publishes neither, so confirm the hose and wand options with the manufacturer against your duct height rather than assuming a standard set will reach. What the specification does fix is the electrical supply: this is a 220 V unit, and a run of ceiling duct may put the nearest available socket a long way from the work. If the supply point is distant or shared with cooking equipment, ask what supply arrangement the machine needs before delivery.
The skin of the pipe: material, seams and old coatings
Galvanised ducting, stainless risers and painted mild steel each answer heat differently. The risks are not dramatic but they are real, and they are the reason a competent operator tests first: heat softens old paint and the coating can lift where the wand dwells; seam sealant and gaskets can soften and start to weep; insulation jackets trap water that then has nowhere to go; and on galvanised steel, very hot water and steam in prolonged contact can dull the zinc into a white powder.
Write one rule into the method and follow it: one square metre, low dwell, one pass, then inspect. Check for lifting paint, weeping seams and dulling on a joint, and only then commit to the run. On a painted duct you may choose a shorter dwell and more passes rather than one slow pass, and on insulated sections you may decide the insulation comes off and is replaced rather than cleaned. Drip edges, drive belts on the fan and any electrical connection box on the duct are wipe-only items on most sites.
Water supply, run-off and the floor beneath the pipe
The HW02 takes a tap-water inlet with a 4-point internal-tooth 1/2 inch joint and carries an 80 L SUS304 tank, so you can either plumb it to a wash point or fill it and work untethered. Which one fits depends on where the duct runs and how far a filled machine can be pushed across a kitchen floor. On a long riser with several metres of horizontal run, a plumbed supply saves refilling trips; on a site with one short riser and a busy servery, tank capacity lets the crew park the machine once and stay up at the work face.
The run-off question matters more than most kitchen managers expect. Grease coming off a duct overhead falls. The plan has to catch it — trays, absorbent matting and sheeting taped under the work area, with the line below closed — and route the collected liquid into the site waste that passes through the grease interceptor, never into a prep sink or a floor drain. Then check the interceptor before the job and after it, because a cleaning run that mobilises a litre of grease into a nearly full interceptor produces a flood, and a flood on a kitchen floor is both a closure risk and a slip claim.
One site condition usually kills the schedule rather than the chemistry: access without closing the kitchen. Plan the job in the window when the extract is off and the line is down, with the isolator for the fan locked and tagged. Steam onto a running fan moves vapour straight into the building, and a fan that starts mid-job puts the crew off the ladder.
How to check the five conditions before you spec the machine
- Scrape a coin across a hidden 100 mm patch of duct. Note whether the film chips, dents or smears. Chipping and hard varnish means high temperature duty; smearing fresh oil means a milder method is enough.
- Measure the highest working point and the distance from the nearest socket and the nearest water point. Take those three numbers to the equipment supplier, not a photograph.
- Identify the skin: galvanised, stainless, painted, or insulated, and list every seam, damper and electrical box on the run as wipe-only.
- Trace the run-off path from the highest pipe to the interceptor, and record when the interceptor was last emptied.
- Agree the shutdown window for the extract fan and the isolator to be locked, and write the duration into the job sheet.
Choosing between a fixed unit and a mobile one for pipework
A fixed steam cleaning machine such as the HW02 suits a kitchen where the duct run sits above a servery with a wash point and a supply nearby, and where the same crew returns to the same zone on a cycle. Its 220 V supply and tap inlet mean it can be parked at a service point and used repeatedly without a charging routine, and dry steam keeps the water actually landing on the duct small, which shortens the time until the area below is safe to walk on again.
Where pipework is spread across several buildings, or where the crew cleans hoods in the morning and vehicles in the afternoon, a mobile steam cleaning machine from the Cleaning Equipment Series is the better fit, since it moves with the work instead of the work moving to it. Cleaning the outside of a kitchen pipe with steam is not one purchase decision; it is a set of site conditions plus a machine matched to them. Send the duct height, the socket and water locations, a close-up of the worst deposit and a note of the shutdown window to the contact page and ask for a configuration and method written around your kitchen, not a catalogue page.
