Coolant Sump Audit Sheet Template: Concentration, pH, Tramp Oil

What is a coolant sump audit sheet for, and when do you use it?

A coolant sump audit sheet is a printable form, with a matching log, that a technical service engineer or a plant fluid manager fills in at every check of a water-mix metalworking fluid sump, so that each reading can be compared with the same sump's baseline at the next audit. It suits a supplier engineer who audits a customer's machines on a round, and a plant that keeps its own fluid records between visits.

The interval comes from the guidance that applies to the site. UK guidance tells employers to measure water-mix fluid concentration with a refractometer, and pH, every week, to check fluid appearance every day, and to check weekly that tramp oil stays low, recommended below 2% (HSE MW5, 2021). The same guidance says to keep records of all tests for at least five years, in a table or graph that makes trends easy to spot (HSE MW5, 2021). In Germany, the pH of used water-mixed coolant is checked weekly, and monthly for glass and ceramic machining (TRGS 611, 2007, section 5.9).

The US OSHA manual gives the reason for a fixed form: data on fluid condition, laboratory analyses and additions "should be tabulated so that relationships and trends in the data can be spotted" (OSHA Metalworking Fluids manual). A reading on a loose note cannot be trended. Use the sheet from the first audit of a sump, so that the first page becomes its baseline. The editable Word sheet, the Excel log and a CSV of the log columns are at the end of this page.

Which sections and columns does the coolant sump audit sheet have?

The coolant sump audit sheet has five sections: scope and criteria set before the round, readings with who measured them, when and where, top-ups and additions, findings rated by risk, and corrective actions with owners. The order follows a site inspection report: scope and criteria first, then findings and risk rating, then corrective actions and a completion plan. The table below previews every column and decides whether each reading can be compared with the sump baseline at the next audit. Example values in the last column are illustrative.

The key row is the corrected concentration: UK guidance sets the recorded concentration as the refractometer reading multiplied by the fluid correction factor (HSE MW5, 2021), so a Brix value written without its factor cannot be compared with a later audit.

In the Excel log, each check of each sump is one row, so the scope columns repeat on every row and a filter on the sump ID shows that sump's history. Columns that do not apply at a site, such as nitrite where German rules do not apply, stay in the log and are left blank rather than deleted, so logs from different sites keep the same layout.

How do you fill in the coolant sump audit sheet at each check?

Fill in the coolant sump audit sheet in six steps: scope rows before the round, readings at the sump, top-ups as they happen, then the comparison, the findings and the actions. Each step uses only what the sheet already holds, so the order matters.

1. Before the round, copy the target ranges, the refractometer factor and the fresh-mix pH for each sump from the product data sheet or the fluid management plan, with its revision. A sump without a criterion gets "criterion not set" rather than a guessed range.

2. At each sump, take the sample at the same point every time. The OSHA manual asks for a written testing procedure that names where and when to collect samples and the person responsible for performing and recording the tests (OSHA Metalworking Fluids manual).

3. Write each reading at the time you take it, with the time and your name. A US EPA field procedure requires that observations be recorded at the time they are made, and that entries be dated and signed or initialed by staff (US EPA Region 4, LSASDPROC-1002-R1, 2021).

4. Record every top-up and addition on the same row. The OSHA manual says that all system additions should be controlled and recorded by a designated person (OSHA Metalworking Fluids manual). If a biocide is added, follow the product's safety data sheet, add it only at the dose the supplier recommends (HSE MW5, 2021), and in the US use a biocide registered by the EPA for metalworking fluids, as the OSHA manual advises.

5. Compare each reading with its criterion and mark the deviation in section 4.

6. Write each action with one owner, one due date and the reading that will show it is done.

How do you mark a coolant reading outside its target range on the audit sheet?

Mark a coolant reading outside its target range by writing the reading, the criterion and the gap on one line in section 4, then rating it act now, watch or no action, with safety findings listed first. A single word such as "low" tells the next reader nothing about how far the reading was off or against which range.

Confirm the reading before you mark it. Take a fresh sample, check that the refractometer was zeroed as its instructions describe and that the right factor was applied. A concentration that is off together with a pH change at the same sump and time is one finding to investigate, not two, and the sheet should say that the cause is not yet confirmed.

Some readings belong at the top of section 4 because the guidance attaches urgent action to them. Dipslide results at or above 10^6 cfu/mL indicate poor control and call for immediate action, which normally means draining and cleaning the system (HSE MW5, 2021). Where German rules apply, nitrite above 20 mg/L calls for a fluid change, a partial exchange or an inhibitor agreed with the fluid maker (TRGS 611, 2007, section 5.3), and a sustained pH drop of more than 0.5 units below the fresh mix is to be avoided (TRGS 611, 2007, section 5.9).

A sump you planned to check and could not, because the machine was down or the sump could not be reached safely, goes on its own line as not checked, with the reason. Writing "OK" over a missed sump turns a gap into a claim that the next audit, or the customer's auditor, cannot tell from a measured result.

What does an illustrative completed coolant sump audit sheet look like?

An illustrative completed coolant sump audit sheet for a three-machine round shows each reading against its criterion, with who read it and when, and keeps the sump that was not checked on its own row. Every range, reading, name and machine number in this example is illustrative and comes from no real site. The table below shows how the readings decide which actions follow (illustrative).

The key row is M-07 concentration: 3.0 °Bx multiplied by the factor of 1.4 gives 4.2%, below the 5.0% floor in this example, so the action is a top-up with a richer premix rather than water (illustrative). The actions section then reads, in this example: A. Kim, raise M-07 to 6% and re-read after one shift, due 2026-11-05; maintenance lead, check the way oil leak on M-08 and run the skimmer, due 2026-11-07; A. Kim, read M-09 when it restarts. The previous audit's actions are marked closed or open in the same section, so the next engineer starts from them (illustrative).

When does a coolant sump audit sheet not fit?

A coolant sump audit sheet does not fit straight oils, sumps without agreed criteria, or a question about why a fluid failed. The sheet records readings against a baseline; it does not set the baseline or find a cause.

Straight oils are not intended to be diluted with water before use (ASTM E1497-23), so the concentration, refractometer factor and premix columns do not apply. UK guidance handles neat oils in separate sheets, such as MW4 for sump cleaning (HSE MW5, 2021). A sump with no agreed target range gives the sheet nothing to compare against; set the range with the fluid supplier first, or write "criterion not set" and leave the deviation column blank.

The sheet is also not a legal record by itself. HSE guidance is not compulsory, but following it normally means doing enough to comply with UK law (HSE MW5, 2021). In Germany, TRGS 611 sets its own measurement intervals for nitrite and pH in used water-mixed coolants, and a sheet that leaves out nitrite does not cover them (TRGS 611, 2007, section 5.3). Check the rules for the site's jurisdiction before you remove a column.

Laboratory analyses and the history of a failed batch need their own records. Attach a laboratory report to the audit row it explains, and keep a complaint or a root cause investigation in its own document, linked by sump ID and date. The CSV version holds the log columns for systems that do not read Excel files.

Coolant sump audit sheet checklist

A coolant sump audit sheet checklist confirms, before the sheet is filed or sent to the customer, that every row can be compared with the same sump at the next audit.

• Each sump has an ID, a location, the fluid name and the sump capacity.

• Each target range names the document it comes from and its revision.

• The refractometer factor for each fluid is written on the sheet.

• The fresh-mix pH is recorded as the baseline for pH drift.

• Each reading has a date, a time, a sample point and the name of the person who took it.

• Each concentration shows both the Brix reading and the corrected value.

• Every top-up shows the volume and the premix concentration.

• Every other addition names what was added and who added it.

• Each deviation states the reading, the criterion and the risk rating.

• Safety findings stand first in section 4.

• Every sump not checked is listed with the reason.

• Every action has one owner, one due date and a completion check.

• Open actions from the previous audit are marked closed or still open.

Lubinpla's Site Inspection task works in the same order from your own documents and site history: it sets the deviation criteria from the baseline before any reading is collected, ties each reading to its observer, time, location and coverage, and returns one cited document for your review.