A steam-cleaning trial on a depot wash bay usually lasts half a day. The machine runs, the bay looks cleaner, and the trial is written off as a success. The problem is that a trial of this kind proves very little on its own. What matters is not how the bay looked afterwards but what the operators can now show: which surfaces responded, which did not, where the time went, and which decisions still rest on guesswork.
This article sets out what a fleet operator should put on paper after the trial, before any equipment is ordered or any wash routine is rolled out across a fleet. It assumes a mixed fleet — vans, buses or trucks, with cabs, exterior panels, service areas such as tail lifts and stepwells, and in some cases engine bays — washed in a yard or indoor bay by an in-house team.
1. Which service areas were actually cleaned, not just sprayed
Fleet service areas are not one surface class. A tail lift has hydraulic rams, pinch points and electrical connectors. A stepwell carries compacted road grime in tread patterns. A refrigerated body has door seals and hinges that trap residue. A cab interior has upholstery and high-touch points. During the trial, record each area separately rather than treating the vehicle as a single job.
For each area, write down the state before cleaning, what was applied (dry steam, wet steam or hot water), how long it took, and the state afterwards. This is the only part of the trial that will still be useful in six months, because it tells you which of your recurring problem areas respond to heat and which need a different method.
If a fixed unit was used, the equipment behind the trial is normally a fleet vehicle steam cleaning machine of the Fixed Steam Cleaning Machine PowerDe HW02 type. Published parameters for that model are 6 kW heating power, a steam temperature of 160°, a vapour pressure of 0.8 MPa, an 80 L tank and a 220 V supply. Those four numbers decide how long you can wash before stopping to refill or wait for recovery, so compare them with what your bay actually demands.
2. Soil type, not surface area, is the unit you should measure
Trials are usually reported per vehicle. That hides the real variable, which is soil. Road film on a side panel behaves differently from brake dust around a wheel arch, differently again from oil film on a chassis member or food residue in a body that carries produce.
Log soil categories instead, and note for each one whether heat did the work or whether mechanical scrubbing was still needed. On engine bays and chassis members, where engine compartment steam cleaning is the usual entry point, the meaningful question is whether the grease softened enough to rinse off without brushing, or whether the operator still spent the majority of the time scrubbing. Write that down honestly. It is the difference between a method that shortens a task and a method that only changes how the task feels.
Any claim that steam replaces detergent should be tested on your own soil, on your own fleet, in your own conditions. Treat supplier statements as hypotheses to check during the trial, not as results.
3. Time, water and stoppages: the three numbers to capture during the trial
Operators tend to remember the cleaning time and forget everything else. Three records are worth more than a general impression:
- Hands-on minutes per vehicle type. Time the operator, not the job. A vehicle that needs twelve minutes of lance work and forty minutes of wiping has a different cost profile from one that needs thirty and twenty-two.
- Water used per vehicle, from the tank or the meter. Low water use is the reason most fleets look at steam in the first place, particularly where a yard has limited discharge capacity or where wash water has to be contained. Record what you actually consumed, including rinse water, because the comparison with your current hose or jet-wash routine only holds if both sides are measured the same way.
- Every stoppage. Refills, heating recovery, hose changes, waiting for the unit to come back up to temperature. Stoppages, not lance time, are what wreck a washing schedule, and they are invisible unless someone writes them down as they happen.
Do not publish or circulate percentages from a single trial. A half-day run on two or three vehicles supports an order of magnitude, nothing finer.
4. What the trial did not cover
Before the report is signed off, list the gaps in your own words. In fleet trials the same few gaps recur:
- The trial ran in mild weather. Cold bays, wind and winter grime change both cycle time and drying behaviour.
- One shift was observed. Night cleaning, shift handover and operator turnover were not.
- The equipment sat near the vehicles. Cable, hose and wand reach across a real yard layout is a different constraint.
- Power and water were convenient. A 220 V supply and a nearby tap inlet are prerequisites, not details; check what your bay offers before assuming the trial setup transfers.
- Waste-water handling was not part of the trial. Where runoff is collected or must be intercepted, the cleaning method changes the load on that system and needs to be checked with whoever owns it.
Writing these gaps into the report is what allows a second, longer trial to be designed properly.
5. Mobile or fixed: decide from your bay, not from the machine
Most first trials use a fixed unit on the ground, because that is the simplest setup. For a yard with a dedicated wash bay, that is often the right answer. Battery-supported mobile steam cleaning machine options matter when vehicles are washed where they park, when the distance between the water point and the vehicles is long, or when several small sites share one machine.
The decision hinges on three site facts: where the vehicles queue, how far the operator has to walk with a lance, and whether a machine has to cross open yard to reach them. Record those three during the trial and the mobile-versus-fixed question usually answers itself.
If your washing pattern, soil mix or bay layout sits between the standard configurations, that is worth raising directly. PowerDe lists customized steam cleaning equipment through its solutions work, so the trial findings are the input for that conversation rather than the end of it.
6. A short review sheet for the operator
Hand the trial to whoever will run it with a single sheet, filled in during the run rather than reconstructed afterwards:
- Vehicle type and the service areas cleaned on it, one line per area
- Soil type per area, and whether heat alone removed it
- Mode used (dry steam, wet steam, hot water) and time in hands-on minutes
- Water consumed, read from the tank or meter
- Every stoppage, with its cause
- Anything the operator had to improvise
- What the operator would change before running this on a full fleet
That last line is the one most often skipped and most often decisive. The people holding the lance know within an hour whether a process fits the shift pattern they actually work to.
If the sheet shows consistent hands-on times, low water use and no unexplained stoppages across two or three runs on different vehicle types, you have a case for a longer trial on the full fleet. If it shows variability, the trial has done its job in a different way: it has told you which part of the process is not yet defined. Either outcome is a usable result, and both are worth more than a well-lit before-and-after photograph.
