Exterior cleaning problems show up as visible dirt. Interior cleaning problems show up as damp seats, lingering odours and vehicles that cannot go back into service on time. Before a buyer asks a supplier for a quote on interior work, the requirement has to be written down in a way the supplier can price and the buyer can check. This article walks through what to put in that specification, using the published PowerDe HW02 data sheet as a worked example, because its product page lists interior vacuuming and disinfection among its uses.
Describe the surfaces before you describe the machine
Walk through one representative vehicle with a notepad and list every area you intend to clean: seats and upholstery, carpets and floor mats, the headliner, the dashboard and steering wheel, air vents and seams, glass and mirrors. For each area, note what is actually on it. Interior soil comes in recognisable states: loose dry material such as sand, dust and crumbs; fresh spills; an oily film on touchpoints such as the steering wheel, grab handles and gear lever; and worked-in grime embedded in fabric.
Each state needs a different action. Loose material has to be removed dry before anything wet touches the surface. An oily film responds to heat and a short dwell time. Worked-in grime needs mechanical action, not just heat. Your specification should say which of these states are in scope, because that is what determines the machine, the attachments and the method. Write down the exclusions too: seat mechanisms, wiring under the seats and anything that must stay dry belong on the exclusion list, not in a footnote.
State the drying requirement, not just the cleaning requirement
The real constraint inside a cabin is moisture. Fabric holds water, headliner adhesive does not like free water, and electronics under the seats make a soaked carpet a repair risk. A specification that only says "clean the interior" invites a machine that works well and leaves the cabin wet. Instead, put a measurable ready-for-service requirement in writing: measure how long your own vehicles actually take to dry after a clean, and state that number as the target the equipment has to support.
This is also where mode selection matters. Ask for a dry and wet steam cleaner rather than a single-mode machine, and state which surfaces use which mode. Dry steam carries less moisture and suits upholstery and headliner work, where drying speed is the limit. Wet steam carries more water and works faster on heavily soiled hard trim and mats. A machine that offers only one of the two forces the operator to accept the weaker result on the other half of the job.
How to read a spec table for interior work
Once suppliers send data sheets, the same reading method applies to all of them. For a vehicle steam cleaning machine, read the numbers as answers to specific questions about your cabin work:
- Steam temperature and pressure are a pair, not two separate capabilities. The HW02 page lists 160 °C at 0.8 MPa. That pair describes one state of steam: how quickly the heat softens oily films and worked-in grime. It does not tell you how fast the machine covers a vehicle, and no data sheet will.
- Mode switching decides the moisture load. The HW02 page lists switching between dry and wet steam, which is what you need for the split described in the previous section: dry steam on fabric, wet steam on hard trim.
- Tank capacity and water inlet decide the work cycle. The HW02 page lists an 80 L SUS304 tank with a tap-water inlet. For interior work, this determines how many cabins one operator can finish before refilling and where the refill point has to be. Specify the refill distance and the drainage route in your document.
- Built-in functions change the workflow. The HW02 page lists a vacuum cleaner alongside the steam unit. Because dry removal is the first step of every interior job, an integrated vacuum changes how many machines you buy and how the task is sequenced.
- Electrical figures are site conditions. The page lists 220 V and 6 kW heating power. Your own electrician confirms a dedicated circuit before you order. The machine's leakage, short-circuit, high-temperature, high-voltage and water-shortage protections protect the machine; they do not replace that check.
- What is missing matters as much as what is printed. Steam run time per tank, preheat time and hose and wand lengths are not on the page. Ask for them in writing. They decide whether one operator can finish a cabin in one pass or has to stop mid-vehicle.
Specify the attachments by task
Interior work is mostly attachments. A crevice tool reaches seat runners, the gap between seats and vent slats. An upholstery brush holds the steam against fabric so the heat has time to work. An extension wand covers the headliner and the rear cabin without a second person holding a door. A hose long enough to reach around the whole vehicle keeps the operator from dragging the machine across the paintwork. Write each of these into the specification as a task, and ask the supplier which items are included, which are optional, and what the part numbers are for the wear items so you can price replacements before you order.
Specify where the work happens
A fixed machine stays where you install it. The HW02 is listed at 1,200 × 800 × 1,200 mm including handles, so measure the delivery route and the final position, then prove that the steam hose reaches every corner of your largest vehicle from that one point. If the cleaning position moves between bays or parking rows, ask about the mobile models in the same PowerDe cleaning equipment range instead of forcing a fixed unit into a moving job.
Then write the four site conditions into the specification and name the person who confirms each one: the electrical circuit, the water supply connection, the drainage route and the airflow that dries the cabin. Grease and oil separation and discharge rules are set by your local drainage authority, not by the equipment supplier. For the drying step, state the arrangement you will actually provide: doors held open, fans running, or a warm-air bay. A specification that names the drying method gets a machine that fits the whole cycle rather than the cleaning minutes alone.
Specify acceptance and a trial
Write the acceptance checks so that four different people would reach the same result. Visual inspection under oblique light shows film left on trim. A white-cloth test on agreed panels shows residue on hard surfaces. A touch-dry check on fabric shows whether the moisture load was acceptable. A seam and crevice check catches what the eye misses, and an odour check after full drying catches what the eye never sees. Set these checks before the trial, not after it.
Run the trial on your own vehicles. Pick one representative vehicle, clean one half and leave the other half as a reference, and time the whole cycle from start to ready-for-service, including drying. Photograph fixed reference points before and after, keep one line of record per vehicle, and write a defect list of what cleaning cannot fix, such as set-in stains and worn fabric, so those items move to the repair plan instead of back to the cleaning crew. One caution on wording: disinfection is listed as a use on the product page, but if your operation needs documented hygiene results, verify them separately. Cleaning and disinfection are different claims, and a data sheet supports neither on its own.
What to ask the supplier in writing
Before you sign anything, send the supplier your surface list and ask them to confirm, in writing, which of those surfaces the machine is offered for. Then close the open points: steam run time per tank and preheat time, hose and wand lengths, the full attachment list with part numbers, what training is included, warranty terms and service response, and what the listed protection functions do and do not cover. Their answers tell you as much about the fit as the data sheet does.
A specification that describes the work — surfaces, soil states, drying limits, site conditions and acceptance checks — produces quotes you can compare against each other and a trial you can judge honestly. Start with one vehicle type, run the trial, and extend the process once the numbers are yours. If you want the open points answered for your cabin list, contact PowerDe with your surface list and site conditions in hand.
