A technical brief is the document that decides whether a custom cleaning machine arrives as engineering or as an expensive experiment. Most buyers send a paragraph: a photograph of a dirty surface, a sentence about the soil, and a request for something that works. A manufacturer reads that as an invitation to guess, and the guess gets built. What follows is the structure we use when a cleaning duty has outgrown catalogue equipment — the sections that belong in the brief and the questions each one has to answer.
1. The duty, written as an operating statement
Start with one paragraph that a stranger could operate from. It should name the object being cleaned, the surface materials, the soil, the cleaning agent being considered, the time available per object, and how many objects per shift. "We clean twelve engine compartments per day, aluminium and painted surfaces, with road film plus oil film, twenty minutes each, one operator" is an operating statement. "We want to steam-clean vehicles" is a category. Everything later in the brief — heater size, tank volume, nozzle choice, cycle design — is derived from this paragraph, so write it with the same care you would give a process specification.
2. The soil, described by behaviour rather than by name
"Grease" covers everything from a machine-tool way oil that is still fluid to an overheated chain oil that has polymerised. Each responds differently to heat, pressure and dwell. Describe the soil by what it does: does it smear under a fingernail, does it flake, is it sticky, has it been baked by process heat, does it contain abrasive grit? State how long it has been on the surface, because a deposit that has been there since the last shutdown is not the same engineering problem as one accumulated overnight. Photograph the worst case in the site's own lighting, with a coin or a ruler in frame so the scale of the buildup is obvious.
If the soil changes across the object, say so. A vehicle with a lightly soiled body and a heavily soiled chassis needs two cleaning behaviours inside one cycle, and that is exactly the situation where commercial steam cleaning equipment with switchable dry and wet steam modes does the job: heat into the heavy deposit first, water into the rinse second.
3. Water, drainage and containment
Water is the constraint that kills more custom designs than cleaning performance does. The brief should state whether tap water is available at the working position and how far away; what the permitted discharge route is; whether an oil-water interceptor exists and who maintains it; and whether run-off has to be captured at all. Sites with no permitted discharge need a low-water process with collected run-off, which changes the machine from a wash unit into a contained system with recovery. Note the tank fill distance, because on a multi-level site a fill point on the wrong floor costs more production time than any nozzle improvement recovers.
Where no configuration solves the site cleanly, customized steam cleaning equipment starts from the drainage map rather than from a product datasheet, and that is the correct place to begin.
4. Utilities as a site survey, not an assumption
Attach a utility sheet: available supply voltage and phase, the socket or distribution point the machine will use, the circuit's rated capacity, the cable run distance from that point to the working position, and whether that run crosses aisles, doors or driving lanes. Record the water inlet type and the fitting size, and the ambient conditions — outdoor exposure, freezing risk, wash-bay humidity. A fixed machine such as the PowerDe HW02 steam cleaner publishes its service requirements plainly — 220 V supply, 6 kW heating power, an 80 L tank and a tap-water inlet — precisely so that a buyer can put them against a site survey before anything is ordered. Include the same numbers in your brief, even when they come from a competitor's datasheet.
5. Geometry, access and what cannot be sprayed
Provide the footprint the machine may occupy, the door widths and any ramps or steps on the route from delivery to the working position, and the reach needed from a fixed standing point. A machine that cleans perfectly behind a step it cannot be moved over is a failed machine. Then list the exclusions: seals, bearings, encoder housings, electrical enclosures, painted or filmed surfaces, bonded joints, decals, sensors and any component the equipment manufacturer forbids pressure washing. Every exclusion line in the brief saves an argument later about who owns a failed seal.
6. Dwell, pass and cycle time
Cleanliness is produced by four variables the operator controls: energy at the surface, dwell time, mechanical action and rinse. The brief should state the cycle time available and, where it is known, the current method's timing per object — how long the crew spends on the heaviest deposit and how many passes it takes. If a current method exists, record it honestly, including its failures; a manufacturer designing blind will over-build, and over-build is what makes a custom machine too heavy to use every day.
7. Acceptance criteria someone on shift can verify
Write acceptance as observable checks, not as a wish. No visible film on the guarding; no loose debris in the channels; no residue in the door seals; floor dry enough to walk within a stated time; no water retained in housings after the stated dwell. For any surface with a coating, add a check for lifting, blistering or a change in sheen after the first pass. For machines with scales or encoders, add a measured check that the reading remains in tolerance after cleaning. Name the person who signs, and what happens on a fail. An acceptance list written by the buyer is the single most valuable page in the brief, because it becomes the trial protocol.
8. Safety, PPE and operator constraints
State the site's permit-to-work rules, the required personal protective equipment, whether a single operator or a pair must run the task, and the maximum reach or working height the crew is allowed to use. Note any site restriction on hot work near oily swarf or solvents, and whether work at height is permitted at all. Also state who may fill the tank and who may open a housing — these are the two points in a steam task where most avoidable incidents occur, and a manufacturer designing the workflow needs to know how your site allocates them.
9. Duty cycle, spares and consumables
Give the working pattern honestly: shifts per day, objects per shift, peak weeks and quiet weeks, and whether the machine must run continuously or in bursts. Duty cycle drives heater sizing, tank volume, hose wear and the service interval far more than cleaning performance does. Ask the supplier, in the same brief, to list consumables and wear items — nozzles, seals, hoses, filters — with expected life under your duty cycle. A machine specified for a lighter duty than the site actually runs is the most common cause of second-year failure.
10. The trial and the sample
Close the brief by offering the sample. A supplier who cannot test your actual part or surface at your actual soil level is guessing, and the machine you receive will be tuned for somebody else's problem. Agree the sample set, the trial location, the parameters to be recorded — mode, working distance, dwell, passes, utility use — and the acceptance checks from section 7. Where the trial reveals that a catalogue unit is nearly right but not quite, that is the moment customisation is worth paying for.
11. What to do with the brief once it is written
Send the brief as written, not as a summary. A supplier reading ten sections of site facts will ask better questions on the first call, and an engineering partner can put that document straight into a design review instead of starting with a questionnaire. Shenzhen PowerDe Automation Precision Equipment works this way on cleaning programmes, from fixed installations to mobile units in the Cleaning Equipment Series. Attach the operating statement, the soil photographs, the utility sheet and the acceptance checks and send them to the contact page, asking for a specification and a trial plan rather than a catalogue page.
