Nonconforming work under ISO/IEC 17025 (clause 7.10)

Clause 7.10 requires a procedure for nonconforming work — any aspect of laboratory activity or result that does not conform to the laboratory's own procedures or the customer's agreed requirements. The procedure must define responsibilities, evaluate the significance of the nonconformity, decide on its acceptability, and inform the customer and recall work where necessary.

Temperature-work examples

• A reference thermometer found out of tolerance at recalibration: every certificate issued since its last good calibration is assessed.
• A mapping dataset with a flat-lined sensor: the sensor is excluded, the impact on hot/cold-spot conclusions evaluated, the report amended.
• A logger calibrated at the wrong points for its use: the certificate is withdrawn and reissued.

ValiTrac's data-quality states (REVIEW REQUIRED, CRITICAL) and validation failures are designed to become nonconforming-work records rather than silent corrections.

The five things the procedure must define

Clause 7.10.1 is unusually specific about what the procedure has to cover, and a procedure missing any of these is a finding on its own terms rather than a judgement call.

The look-back, which is where the work is

A reference thermometer found 0.08 °C out at recalibration is not one problem; it is every certificate issued since the last good calibration. The look-back has to establish when the drift plausibly began — intermediate check data is what makes this answerable rather than a guess — and then, for each affected certificate, whether the error was large enough to change a reported value beyond its stated uncertainty or to flip a conformity statement.

Most of them will be unaffected, and saying so with a calculation is the point. The ones that are affected have to be reissued and the customers told. A look-back that concludes no impact without showing the arithmetic is the version that gets challenged.

Worked examples from temperature work

• Flat-lined sensor in a mapping study: exclude it, record the exclusion and its range, reassess whether the remaining sensors still satisfy the study design, and amend the report. If the excluded sensor was the hot spot, the study no longer supports its own conclusion.
• Logger calibrated at the wrong points: the certificate does not cover the range of use. Recall it, recalibrate, and assess whether the customer relied on it in the uncovered range.
• Conformity statement issued without a decision rule: the results are sound, the statement is not. Reissue the certificate with the rule named, referencing the version it replaces.
• Calibration performed with an expired reference certificate: traceability is broken for the period, regardless of whether the reference turns out to have been in tolerance.

Where 7.10 stops and 8.7 starts

Clause 7.10 is containment: stop it, assess it, fix this instance, tell whoever needs telling. Clause 8.7 is corrective action: work out why it happened and stop it recurring, then check the action worked. Clause 7.10.2 makes the link explicit — where the evaluation indicates the nonconforming work could recur, the corrective-action procedure applies. Recording nonconformities and never raising a corrective action produces a log that grows and a laboratory that does not improve.

The healthy signal is a nonconforming-work log with entries in it. An empty log means the detection mechanisms are not working, and assessors read it that way.