Most steam trials fail at the paperwork, not at the nozzle. A technician cleans a dirty bay, everybody agrees the machine works, and six months later the purchase is cancelled because nobody can say what it replaced, what it cost in labour minutes, or which asset classes it actually covers.
A trial record is not a summary of a good afternoon. It is the document a purchase order, an operator's daily routine and an auditor all have to rely on. This article sets out what to write down before the machine is switched on, which fields to capture while it is running, and how to turn the result into a scope a manufacturer can quote against.
Write the record for three readers, not one
Before the trial, decide who will read it, because each reader needs something different:
- Whoever signs the purchase order needs a comparison: the method you use now versus the method you trialled, on the same soil, the same area and the same labour. Without a side-by-side number the decision becomes a judgement call, and judgement calls lose to whichever vendor visits last.
- Whoever has to repeat the result needs settings, not impressions: which mode, which nozzle, how many passes, how fast, how far from the surface. If that information stays in the technician's head, the machine is bought once and used badly forever.
- Whoever answers an inspector or a food-safety, hygiene or waste audit needs a dated, signed record of what was cleaned, how, and with what chemical load. That record is what makes a steam trial defensible in front of an auditor, even when cleaning time is unchanged.
If your trial record cannot serve all three readers, treat the trial as incomplete and run it again. Repeating a one-day trial is cheap; buying the wrong machine is not.
Record the baseline before the machine is switched on
The most common mistake is measuring the new method and nothing else. Spend the first hour of the trial on the method you already use:
- Describe the asset and the soil: surface material, coating, age, and what is on it (road film, engine grease, cutting fluid, food residue, biological soil). "Very dirty" is not a baseline.
- Photograph the same reference points you will photograph afterwards, with something in frame for scale and the same lighting and angle.
- Time the current method end to end: preparation, application, dwell, mechanical scrubbing, rinse, drying, and the waiting time before the asset returns to service.
- Note what the current method consumes and disposes: water volume, detergent type and quantity, and where the run-off goes.
- Write the acceptance criterion down in advance: for example "the bay floor passes the same visual check the supervisor uses today, with no re-scrub", or "one operator completes the daily vehicle wash without a second pass". Fixing the target after the trial is how trials get talked into success.
What sets the result: mode, then technique
On industrial steam cleaning equipment the result is set by a short list of variables, and each one belongs in a column of your sheet. What the manufacturer publishes tells you which variables are fixed and which ones you have to measure yourself.
Mode comes first, because it changes the whole outcome. The driving-style units in the range carry dry steam, wet steam and hot water modes for indoor garages and narrow outdoor parking spaces; the PowerDe PWD02 driving style steam cleaning machine is offered with and without a battery, which sets how far a mobile trial can move between bays. Record the mode used for every asset, not just once for the day.
Technique is the second variable, and it is the one operators leave undocumented:
- Accessory and nozzle. The same machine with the wrong attachment leaves heavy grease on the surface and simply moves it elsewhere.
- Stand-off distance, travel speed and passes. Log all three per asset class, or the result cannot be repeated by the next shift.
- Time per unit of work. Minutes per square metre for floors, minutes per vehicle, minutes per machine tool or per bed frame. This is the field that converts a cleaning result into a cost.
- What did not come off. List the residues that survived, and what you had to do afterwards. A trial record with no failures is not a record, it is marketing.
Record the machine settings the datasheet already fixes
For a fixed station, start from the published duty. The Fixed Steam Cleaning Machine PowerDe HW02 detail page lists 6 kW heating power, a steam temperature of 160 degrees Celsius and a vapour pressure of 0.8 MPa, an 80 L SUS304 tank, a 220 V supply, and a tap-water inlet on a 4-point internal-tooth joint (1/2 inch).
Enter those as the specification, then write beside them what your own instrument read at the nozzle during the trial. Catalogue values describe the machine; your values describe your water temperature, your inlet pressure and your operator.
Where a figure is not published, make it a measured output of the trial instead of an assumption. The hand-pushed PowerDe HMW3, listed for medical equipment steam cleaning including hospital beds and medical machinery, publishes a 4.5 kW PTC semiconductor heater, a 50 L clean water tank, a 48 V battery working supply, dry and wet steam modes, and dimensions of 1,150 x 520 x 1,030 mm.
Steam temperature, steam pressure, battery runtime, weight, hose length, noise and water use per hour are not stated on that page. Those blanks are the columns your sheet must fill, and the questions to send back to the vendor with your measurements attached.
Compare on identical work, or the comparison is worthless
Three rules keep the numbers honest:
- Split the same asset. Clean half a bay, one of two identical vehicles, or the same machine tool on consecutive days. Never compare a clean area against a dirty one.
- Keep labour constant. Same operator, same shift length, same task list. A trial run by your fastest technician against your slowest baseline produces a number nobody will believe.
- Run the trial at the real pace. A demonstration at half speed, with a vendor's operator, proves the machine works. It does not prove your crew can hold the throughput, which is what the purchase order pays for.
Where the machine carries protection functions, note how they behaved in your conditions rather than assuming they never matter. On the HW02 the page lists leakage, short-circuit, high-temperature, high-voltage, water-shortage and high-voltage-explosion protection.
If any of these trip during a wet-floor or cold-start trial, write down the circumstances. That changes the utility supply and the operating routine you will need.
Add the cost, safety and utility fields that decide the order
Cleaning quality opens the trial; these fields close or kill the purchase. Record each one per asset class:
- Labour minutes per asset, before and after, including dwell and drying time, and whether the asset can return to service sooner.
- Utility fit. Note the supply available where the work is actually done: 220 V at the fixed station, or battery supply in a bay with no socket.
- Reach and refill. Cable reach, water inlet availability, and whether a tank refill is needed mid-task.
- Consumables changed. Which detergent was eliminated or reduced, and what that means for storage, handling, PPE and effluent. Do not report a water saving you have not metered; write the observed volumes and let the comparison speak.
- Operator burden. Weight to push, hose drag, noise, and how far the unit travels through your layout. The HMW3 is a hand-pushed unit at 1,150 x 520 x 1,030 mm; the driving-style PWD01 and PWD02 exist for tight garages and parking areas where pushing distance is the constraint.
- Failure and rework. Anything re-cleaned, anything the machine could not touch, and any asset class you now know belongs to a different method.
Close the trial with a one-page sheet and a signature
Close with one page per asset class, not a folder of notes. At minimum: date, site, asset, soil description, machine and mode, published parameters used, measured temperature and pressure, nozzle and technique, minutes per asset, what failed, chemicals and water actually used, PPE required, and a pass or fail against the acceptance criterion set before the trial.
Have the operator, the supervisor and whoever owns hygiene sign it. An unsigned sheet is an opinion; a signed one is evidence.
Turn the record into a scope request, not a catalogue request
That record also gives you a shortlist. If your measured times and residues match the fixed-station duty, a 220 V unit with an 80 L tank may be the right core of the routine. If the blanks — runtime, reach, mobility — decide the answer, then a battery-fed hand-pushed or driving-style unit is the one to scope.
Where the trial shows a duty that no standard unit covers, that is the point at which to open a customised equipment survey or bring the requirement into engineering and testing services. Configuration, process parameters and the acceptance method then get agreed in the same document you have just built. A trial record worth having is one a manufacturer can quote against without asking you what you meant.
