A buyer will not accept a machine for cleaning grease-covered factory machinery on the strength of a brochure. Acceptance criteria have to be written before the machine arrives, because a grease deposit behaves differently from dust or loose swarf: it insulates, it hides cracks and weeping joints, it carries abrasive grit that scratches whatever it is wiped across, and once it has been baked by repeated hot cycles it is no longer the same substance as the oil that made it. This article sets out how a facility can turn that mess into criteria a supplier can be held to, and a trial that produces evidence rather than an impression.
Say what is actually on the machine
Write the deposit down before you write the criteria. Cutting fluid and way-oil film sit differently from hydraulic oil that has been crawling out of a seal for months, which sits differently from quench oil carrying a fine abrasive, and differently again from a baked-on carbonised skin on a surface that runs hot. Age matters as much as type: a film laid down since the last clean responds quickly, while a deposit that has been cooked onto a guard, a frame or a finned surface has changed character. Record where the film comes from. A drip point that is still weeping will re-soil a cleaned surface within days, and a cleaning criterion that ignores the source will be failed by the machine, not by the cleaning.
Photograph the machine as found, from the same positions you will use for the after photographs. Keep those images with the enquiry. A supplier who can see the deposit gives a more useful answer than one working from the phrase "heavy grease", and a buyer who can compare two after photographs against the same before photograph settles arguments about what was actually achieved.
Decide what "clean" means for each surface
A single pass mark applied to a whole machine causes trouble, because factory machinery is not one surface. Write down the surface classes you are dealing with and state what acceptable looks like for each of them.
Bare machined ways and sliding surfaces: the criterion here is usually film and grit removal without damaging the surface or leaving residue that will affect movement. Painted guards and frames: the criterion is deposit removed with the coating intact, since steam on an old or poorly adhered coating can lift it. Nameplates, scale graduations, wiring, cable glands and labels: the criterion is that these remain readable and undamaged, and a cleaned machine whose labels have gone is a failed clean, not a finished one. Openings, bearings, shaft ends, vents and terminal boxes: the criterion is that these were protected and that no run-off travelled into them.
Write each class as an instruction someone can look at and check. "No visible oil film on the guard; coating not lifted; nameplate legible; no water tracked past the motor vent" can be checked by a second person. "Machine looks clean" cannot.
Split the criteria into what gets measured and what gets judged
Some of your criteria can be verified against a record, and some can only be verified by looking. Keep the two lists apart so that nobody quietly argues a judged result into a measured one.
Measured items typically include the area covered and the time taken, the water actually used and where the run-off went, what had to be shielded and how long that shielding took, which mode the machine was run in for each surface, and how much consumable the machine consumed and at what interval it needs replacing. Judged items typically include finish quality on each surface class, whether edges, weld seams and corners came up clean, and whether anything was damaged. Both sets belong in the acceptance document, with the judged items recorded by a named person against the surface classes you defined.
Put the specification rows into the criteria, not the sales sheet
Acceptance criteria for machinery need the machine's published operating rows in the same document, because a criterion that depends on a utility the machine cannot use is worthless. Ask every bidder to confirm the same rows and hold those confirmations with your criteria.
For a fixed machine, look at Fixed Steam Cleaning Machine PowerDe HW02 as an example of the specification sheet you should expect to receive: that page records 220 V working voltage, dry and wet steam modes, a tap-water inlet with a 1/2 inch four-point internal-tooth joint, an 80 L SUS304 tank and a footprint of 1,200 x 800 x 1,200 mm including handles. Those rows let you check whether the machine can be fed, moved and parked where your machinery stands. Do not transfer figures between models: a fixed corded machine and a mobile battery-fed machine have different working limits, and published rows differ from one machine to another. Where a row is not published for the model you are quoting, treat it as a question, not an assumption.
Make dry steam and wet steam a decision in the criteria
A machine that switches between dry and wet steam gives you two different working effects on the same surface, and your criteria should say which one applies where. Dry steam is the drier side of the choice: it works on a deposit with less moisture reaching the surroundings, which matters close to electrical parts, insulation and porous surfaces. Wet steam puts more heat and more water into the surface, which is what you want on a heavy deposit on open metal, and what you do not want next to a bearing or a bundle of cable. Record the mode used for each surface in the trial, and carry it into the standard. A cleaning method that does not say which mode was used cannot be repeated by the next shift.
Set the trial boundary and the evidence it must produce
Do not accept a demonstration that shows the machine running. Define a bounded trial: one named machine or one named group of machines, one deposit condition, one operator pair, and a written scope stating what is excluded. Then state in advance what the trial has to produce.
The record should include the sequence of work with stage times, so you can see how much of the job is the cleaning itself and how much is shielding, moving and waiting. It should include what was protected and what that cost in time. It should include water use and the route the run-off took, including whether it reached a drain you are allowed to use it on, and how oily run-off was contained. It should include the finish on each surface class against your criteria, with photographs. It should include one line you were sure would go wrong: the corner, the seam, the finned surface. That line tells you more about the machine's fit than the flat panels do.
Handle the run-off before the machine arrives
Grease coming off machinery does not disappear; it goes somewhere. A facility that has not decided where will find the answer chosen for it. Your criteria should state the route for run-off, how oily run-off is separated or collected, which drains in that bay may receive it, and what the floor has to look like afterwards. Where a washdown bay exists, confirm that its drainage and its floor finish can take the volume your trial produces. Where one does not exist, containment becomes part of the work, and therefore part of the cost and the time.
Ask also what the surroundings tolerate. Steam and hot run-off near an adjacent machine, an electrical cabinet, a gas line or a stored material is a scope question, not an operator's judgement call on the day.
Make the safety rows part of acceptance
Machines intended for this class of work are described with protections around electrical and water operation. Ask which protection each is, what it senses, where it sits, what the machine does when it trips, and whether it locks out or simply resets. Then translate the answers into duties at your site: who checks the inlet and strainer, who inspects the cable and coupling, how a trip is recorded rather than forgotten, and who is allowed to reset.
Those duties belong in the acceptance document because they decide whether the machine can be run in your plant on a normal day. Ask separately about consumables, wear parts and the interval they need, and about the warranty terms that depend on them. A machine accepted on cleaning result alone, with no maintenance plan attached, tends to fail quietly at the first season when nobody has the part.
Ask the supplier questions that produce comparable answers
Send the same list to every bidder so the replies can be compared line against line.
Ask which published rows apply to the machine you are being quoted, and in which document. Ask what the machine needs from the site: power, water supply and inlet connection, drainage, floor space and access, and clearance for maintenance. Ask how the machine is moved to the work and how much of the cleaning duty falls on the site rather than on the machine. Ask which protections are fitted and what each one does. Ask what the maintenance plan is, at what interval, with which parts, and at what cost of ownership those parts arrive. Ask what the supplier needs from you to confirm the machine suits the deposit: photographs, a sample panel, a named machine, a trial window.
Put the deposit description and your criteria sheet in front of the maker rather than a reseller where you can, and ask about the customized steam cleaning equipment route when your machinery does not fit a standard configuration. Customisation questions asked after acceptance are expensive; the same questions asked in the enquiry are ordinary.
Compare the whole industrial steam cleaning equipment offer, not the headline claim
Set the trial records of two or three offers side by side on the same deposit condition and the same surface classes. Compare the time to complete the bounded scope, the shielding time, the water and run-off burden the clean created, the finish on each surface class, the mode flexibility you actually used, and the maintenance interval and consumables the offer carries. The difference between offers is rarely the headline claim; it is the number of duties the clean pushes onto your plant and how well the published rows match what your bay can give.
A useful habit is to convert a passed trial into a written standard the moment it passes: the machine, the mode per surface, the sequence, the shielding list, the run-off route, the finish criteria and the sign-off. That document is what a second shift produces the same result with, and it is also what you hand back to the supplier when a machine does not perform as it did on the day it was accepted.
A short sign-off list for the criteria document
Before you sign an acceptance document, check six lines. The deposit is described by type, age and source, with the re-soiling point named. Each surface class has its own definition of acceptable, with damage stated as a failure. The measured items and the judged items are separated and someone is named for the judged ones. The specification rows for the quoted machine sit in the same document, and no figure has been transferred from another model. Run-off has a route, and containment time is counted. The trial scope is bounded, and the photographs, stage times and the one difficult corner are in the record.
If those six lines are present, acceptance stops being a matter of opinion. The machine either meets the criteria your plant wrote, or it does not, and both sides know which.
