Out-of-Tolerance Decision Flowchart

Step-by-step procedure when calibration equipment is found out of tolerance. Based on ISO 9001:2015 Clause 7.1.5 requirements.

Equipment found OUT OF TOLERANCE during calibration

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1 Quarantine the instrument immediately

Remove from service — attach a red "DO NOT USE" label
Record the as-found reading and the expected reading
Note the date, time, and who discovered the deviation
Do NOT adjust or recalibrate yet — the as-found data is evidence

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2 Assess the impact on previous measurements

When was the instrument last known to be in tolerance? (last cal date)
What products/tests were measured between then and now?
Could the OOT condition have affected any pass/fail decisions?
Calculate the error magnitude — how far out of tolerance?

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Did the OOT condition potentially affect product quality or test results?

YES — affected

3a Raise a Non-Conformance Report (NCR)

Document the affected products/measurements
Initiate product recall, re-inspection, or re-test as needed
Notify the customer if affected product was shipped
Record corrective actions in your QMS

NO — not affected

3b Document the assessment

Record that impact was assessed and found negligible
State the rationale (e.g. "error within product tolerance")
Retain as evidence for audit trail

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Can the instrument be recalibrated and returned to service?

YES

4a Recalibrate and verify

Adjust/repair the instrument
Perform full recalibration
Issue new calibration certificate
Record as-left readings

4b Retire or restrict

Mark instrument as "RETIRED" or "RESTRICTED USE"
If restricted: document the limited range/conditions
Update the calibration register
Plan replacement if needed

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5 Determine root cause and prevent recurrence

Why did it go out of tolerance? (damage, drift, environmental, age)
Should the calibration interval be shortened?
Are similar instruments at risk? Check the same make/model.
Update the calibration schedule with revised interval if needed

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6 Update records and close out

Update the calibration register with new status
File the OOT report, NCR (if raised), and new certificate
Close the corrective action in your QMS
Brief relevant staff on any procedural changes

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Instrument returned to service (or retired) — records complete

Quick Reference: OOT Record Checklist

Item	Required Information	Recorded?
Asset ID / serial number	Instrument identification
As-found reading	The actual reading before adjustment
Expected reading	What the reference standard shows
Error magnitude	Difference and direction (over/under)
Discovery date	When the OOT was found
Last known good date	Previous calibration date (in-tolerance)
Products/tests affected	List of items measured in the suspect period
Impact assessment	Significant / not significant + rationale
Corrective action	Recalibrated / retired / restricted + details
Root cause	Why it happened and prevention measures
As-left reading	Reading after adjustment (if recalibrated)
New certificate ref	Reference number of new calibration certificate

ISO 9001:2015 Clause 7.1.5.2: "When measuring equipment is found to be unfit for its intended purpose, the organization shall determine if the validity of previous measurement results has been adversely affected, and shall take appropriate action as necessary." This flowchart implements that requirement. For UKAS-accredited laboratories, ISO 17025:2017 Clause 7.7.1 imposes additional requirements for handling nonconforming work. This document does not constitute legal or certification advice. Consult your certification body for definitive requirements.