Short answer
Calibration helps to understand the reference chain on which a measurement result is based and its uncertainty. A label on the instrument does not, on its own, show that the test result is accurate enough for its purpose or that all measurements are traceable.
Source: S101
Technical explanation
NIST explains metrological traceability as relating a measurement result to a reference through a documented, unbroken chain of calibrations. Each link in the chain contributes to the uncertainty. Traceability alone does not guarantee fitness for the intended use; the measuring range, the method and the required uncertainty are also evaluated. In hose testing, this approach should be considered not only for the pressure gauge but also for other measurements that affect the result.
Source: S101
Topic-specific checkpoints
| Item | Description |
|---|---|
| Instrument | Identification and measuring range used |
| Certificate | Results, references and uncertainty |
| Use | Suitability comparison against the required accuracy |
| Impact analysis | Related tests in case of nonconformance |
Source: S101
How to evaluate it in practice
Add the serial number, the range used, the certificate, the validity assessment and the check date to the test instrument record. Check whether the measurement points in the certificate cover the range of use. If the instrument has suffered an impact, do not look only at the calendar date; initiate a re-evaluation. Link reports to the instrument identification so that, when a nonconforming instrument is found, you can query which past tests may have been affected. Do not set the calibration interval from this guide as a universal number of years. Do not claim traceability based only on the existence of a certificate unless the measurement chain, instrument identification and calibration scope match.
Original editorial recommendation; not a clause of a standard.
Frequently asked questions
Is every pressure gauge with a calibration certificate suitable for every test?
No. The range used, uncertainty, resolution and the needs of the test must be evaluated together.
Source: S101
Source coverage
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S101
NIST Policy on Metrological Traceability NIST · accessed 2026-10-19 Introduction; Policy Statement; traceability and fitness for purpose