What should a monthly coolant analysis report to the plant show?

This guide covers water-miscible metalworking fluids in machine sumps and central systems, reported monthly by a fluid supplier or the plant's own coolant owner. It does not cover straight oils, laboratory depletion analysis or air sampling. Target ranges come from each product's data sheet, and test intervals from the rules where the plant operates.

What do you need before writing a monthly coolant analysis report?

Before writing a monthly coolant analysis report, you need the target ranges for every sump, the month's readings, a log of every addition, the actions and visit notes, last month's open risks and the name of the plant reader. A report written without the target ranges can list numbers but cannot tell the plant which of them need action.

Take the sump identity and targets from one place. The HSE example record sheet carries the location, machine, asset reference, product, sump capacity, refractometer correction factor and operating concentration and pH ranges at the top of each sheet (HSE MW5, 2021). Copy those into the report header for each sump.

Collect the additions next. The US OSHA best practices manual says that "All system additions should be controlled and recorded by a designated person(s)", including biocides, additives, concentrates, and water or oil added to make up losses (OSHA, accessed 2026). Top-up volumes per sump show leaks and drag-out that a single reading misses.

Finally, decide who reads the plant copy. A maintenance manager wants the actions and dates; an environment, health and safety (EHS) manager wants the bacteria, nitrite and skin-risk lines. Write the summary for the named reader and keep the full table for both.

How do you build a monthly coolant report step by step?

Building a monthly coolant report takes five steps: summarize readings against limits, list the actions, list open risks, set the next checks, and screen what goes to the plant. Each step produces one section of the report, in that order.

1. Summarize readings against limits. For each sump, give the lowest, highest and last value of each reading next to its target range, and count the readings outside the range. Do not report a monthly average alone, because one bad week disappears into it.

2. List the actions. For each out-of-range reading, give the date, what was done, the amount added and the retest value after mixing.

3. List open risks. Give each unresolved condition an owner, a next check date and what happens if it is not closed.

4. Set the next checks. Name the reading, the sump, the date and who takes it, including any interval change agreed under local rules.

5. Screen the plant copy. Remove internal notes, keep every reading and every action, and send.

HSE recommends keeping coolant records in a table or graph "to make it easy to spot trends and act on the results to maintain fluid quality" (HSE MW5, 2021). A small trend line per sump next to the step 1 table does this without extra text. Steps 3 and 5 need the most judgment, and the next sections cover them.

Which coolant readings and limits belong in a monthly coolant report?

A monthly coolant report should carry concentration, pH, tramp oil, bacteria by dipslide, top-up volume and, where German rules apply, nitrite, each paired with its target range and the source of that range. The table below decides which readings go in the summary and where each limit comes from.

The concentration row needs the most care: state the raw refractometer reading and the factor, because each product has its own refractometer factor (Quaker Houghton, 2020). Refractometers also tend to read higher than the actual concentration over time as tramp oil builds up (Master Fluid Solutions, 2019), so a rising concentration beside rising tramp oil may be a reading effect. Where the plant is outside Germany, drop the nitrite row unless the fluid supplier or a local rule asks for it, and say so in the header so the plant knows the omission is deliberate. Keep the same rows in the same order every month, so the plant can compare reports side by side.

Which open coolant risks should the monthly report list for the plant?

The monthly coolant report should list every condition that is outside its range, moving toward a limit, or waiting on someone, each with an owner, a next check date and the consequence if it stays open. Open risks sit in their own section so the plant does not read them as solved because the month has ended.

Typical open coolant risks include:

• A dipslide count that rose but stays below the HSE action level of 10^6 CFU/ml (HSE MW5, 2021).

• A pH falling week by week toward the 0.5-unit drop that TRGS 611 says to avoid in Germany (TRGS 611, 2007).

• A nitrite result above 10 mg/l, which returns a German site to weekly nitrite tests (TRGS 611, 2007).

• Tramp oil above the recommended 2% with its leak source not yet fixed (HSE MW5, 2021).

• Rising top-up volume on one machine with no cause found.

• A sump due for draining and cleaning that has not been scheduled.

For each risk, write what the supplier will do and what the plant must do. A leaking way lube line is a plant maintenance job; a biocide addition is a supplier job done at the dose the supplier recommends (HSE MW5, 2021). A risk without a plant owner has nobody to close it. Close a risk only when a retest shows it inside the range.

What should stay out of the plant's copy of a monthly coolant report?

The plant's copy of a monthly coolant report should leave out the supplier's internal notes: pricing and margin, sales opportunities, remarks about named plant staff, other customers' data, and guesses not yet checked. Every reading, every action and every open risk stays in, including the ones that reflect badly on the supplier.

Removing a reading is not screening. HSE guidance says that if a third party undertakes the checks, the plant should "review the results and remedial actions taken" (HSE MW5, 2021), and the plant cannot review a result it never received. In Germany the employer must make sure test results and actions are documented in a test log or test report (DGUV Regel 109-003, 2026, section 7.4.1), so the supplier's report may become part of that record.

Handle suspected causes carefully. Write "possible cause, not yet confirmed" next to a hypothesis such as a leaking hydraulic seal, and name the check that will confirm it, rather than stating the cause as a finding. Keep the internal version, with the commercial notes, in the supplier's own file.

A plant copy built this way also serves later, when the supplier has to show what the service delivered over the year; see how to show technical service value before contract renewal for that practice.

How do you check a monthly coolant report before sending it?

A monthly coolant report is ready to send when every sump shows its readings beside a target range, every out-of-range event has an action and a retest, every open risk has an owner and date, the next checks are set and internal notes are gone. The check table below decides whether the report goes out or goes back for a fix.

The open risks row needs the closest look. A risk listed without an owner or a date reads to the plant as information, not as a task. Check the plant copy against the internal version line by line: only the commercial notes should differ. Read the summary once more as the named plant reader would, without the supplier's background knowledge: if a sentence needs a phone call to understand, rewrite it before the report goes out.

Monthly coolant report mistakes that hide sump problems

The commonest monthly coolant report mistakes hide a sump problem behind a tidy summary: monthly averages, corrected concentrations without the factor, risks closed without a retest, text copied from last month, and missing top-up volumes. Each makes the report shorter and the plant less informed.

Averages are the first trap. A sump that ran lean for one week and rich for the next can average inside its range while the plant saw corrosion and residue in the same month (illustrative). Report the low, high and last values instead.

The second trap is the method. A corrected concentration without the raw reading and factor cannot be checked, and a change of product without a change of factor shifts every value.

The third is closing a risk on the supplier's word. A risk is closed by a retest value inside the range, dated and recorded.

The fourth is copying. A report whose text matches last month's except for the numbers suggests nobody looked at the trend; the open risks section should change when the sumps change.

The fifth is leaving out additions. OSHA's manual calls for recording all system additions (OSHA, accessed 2026), and a top-up log that doubles on one machine points to a leak before any reading does. In Lubinpla, the account technical support status task lists a project's condition measurement history and worklogs for a chosen period and produces an activity summary and an open risk list.