ISO/IEC 17025:2017 Clause 6.4 (Equipment) requires a laboratory to have access to the equipment needed to perform its activities correctly, and to calibrate that equipment whenever measurement accuracy or uncertainty affects the validity of reported results or is required to establish metrological traceability. Equipment must be handled, transported, stored, used, and maintained so it is protected from contamination and deterioration; it must be labeled to indicate calibration status; and any equipment that is overloaded, mishandled, gives suspect results, or is shown to be defective or outside specified requirements must be taken out of service and the effect on previous results examined. Clause 6.4 works hand-in-hand with Clause 6.5 (metrological traceability): 6.4 governs the equipment itself, while 6.5 governs the unbroken chain that makes its readings meaningful. Assessors read the program through its equipment records, so a complete, current equipment register is the practical heart of 6.4 conformity.
Clause 6.4.6 sets two triggers for calibration: when the measurement accuracy or uncertainty of the equipment affects the validity of reported results, and when calibration is required to establish the metrological traceability of those results. This is deliberately risk-based — not every device needs the same treatment, but anything whose error could change a reported value or a conformity decision must be calibrated against traceable references. The laboratory must also establish a calibration programme and review and adjust it as needed, which in practice means setting and justifying intervals rather than defaulting everything to twelve months.
Clause 6.4.8 requires equipment to be labeled, coded, or otherwise identified to indicate its calibration status, including the date of last calibration and the date or criterion for the next. Clause 6.4.13 specifies the records to retain for each item that can affect results: the identity of the equipment including firmware version where relevant; the manufacturer's name, type, and serial number; evidence of verification that it meets specified requirements; the current location; calibration dates, results, adjustments, acceptance criteria, and the due date of the next calibration; the maintenance plan and maintenance carried out; and details of any damage, malfunction, modification, or repair. Missing or incomplete records here are among the most common 17025 findings.
When it is necessary to maintain confidence in equipment performance between calibrations, Clause 6.4.10 requires the laboratory to carry out intermediate checks according to a defined procedure. A typical pattern is a quick comparison against a stable check standard or reference material — for example, weighing a control mass each day a balance is used, or verifying a gage block stack against a master — so drift or damage is caught before it invalidates a batch of results rather than at the next annual calibration. The check method, its acceptance criteria, and the action taken on a failure all need to be documented.
Clause 6.4.9 requires that equipment which has been overloaded or mishandled, gives suspect results, or is shown to be defective or outside specified requirements be taken out of service, isolated to prevent use, and clearly labeled until verified to work correctly. Critically, the laboratory must examine the effect of the defect on previous measurements and invoke its nonconforming-work procedure (Clause 7.10) where results may have been affected. This is the 17025 analogue of the AS9100 validity-of-previous-results obligation — covered in full in our out-of-tolerance investigation procedure.
CalibrationOS maintains an equipment register carrying every record element Clause 6.4.13 enumerates — identity, manufacturer/type/serial, location, calibration dates and results, due dates, maintenance, and repair history — and surfaces calibration status for labeling. It schedules intermediate checks against defined criteria, and when an item is recorded suspect or out of tolerance it runs reverse traceability to examine the effect on previous results. Every change is written to a SHA-256 hash-chained audit trail, so a 17025 assessment becomes a guided record review rather than a scramble.
Clause 6.4 (Equipment) of ISO/IEC 17025:2017 covers access to required equipment, calibration when accuracy or traceability demands it, handling and maintenance to prevent deterioration, calibration-status labeling, intermediate checks, removal of suspect equipment from service, and the equipment records the laboratory must retain.
Clause 6.4.6 requires calibration when the measurement accuracy or uncertainty of the equipment affects the validity of reported results, or when calibration is needed to establish metrological traceability. The laboratory must maintain a calibration programme and review intervals rather than apply a blanket default.
Clause 6.4.13 requires records of equipment identity and firmware, manufacturer/type/serial number, verification of conformity, current location, calibration dates/results/adjustments/acceptance criteria and next-due dates, maintenance plan and maintenance performed, and any damage, malfunction, modification, or repair.
Intermediate checks (Clause 6.4.10) are defined-procedure checks performed between full calibrations — such as weighing a control mass or verifying a check standard — to maintain confidence in equipment performance and catch drift or damage before it invalidates results.
Clause 6.4.9 requires isolating and labeling suspect or defective equipment to prevent use, and examining the effect of the defect on previous measurements — invoking the nonconforming-work procedure (Clause 7.10) where prior results may have been affected.
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