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“Uncertainty-noise” Le Mans
13
Acoustique
&
Techniques n° 40
1.2 Reference standards
Several reference standards ask directly or indirectly (through the control of the measuring equipments) for the estimation
of the uncertainty of measurement, such as:
- EN ISO 9001:2000 «Quality management systems – Requirements»
This standard specifies in 7.5.1 c) the use of suitable equipment, in 7.5.2 b) the approval of equipment and in 7.6 where
necessary to ensure valid results, measuring equipment shall
a) be calibrated or verified at specified intervals or prior to use, against measurement standards traceable to international
or national measurement standards; where no such standards exist, the basis used for calibration or verification shall be
recorded;
b) be adjusted or re-adjusted as necessary;
c) etc.
- EN ISO 10012 : 2003 «Measurement management systems – Requirements for measurement processes and measuring
equipment»
This standard specifies particularly in 7.3.1 Measurement uncertainty :
«The measurement uncertainty shall be estimated for each measurement process covered by the measurement management
system, etc.»
- EN/ISO/IEC 17025-2000 «General requirements for the competence of testing and calibration laboratories»
This world-wide reference standard for the accreditation of laboratories specifies, in particular in 5.4.6, that testing laboratories
shall have and shall apply procedures for estimating the uncertainty of measurement and, in 5.10.3.1 c), that test report,
when the uncertainty affects compliance to a specification limit, shall include a statement on the estimated uncertainty of
measurement.
This standard can also be used as reference document by non-accredited laboratories as the other EN ISO 9001 and EN ISO
10012 standards. In fact, the very large majority of measurements in the world is made in industry and without any kind of
accreditation. Industry is using measurements for the control of the quality of their products. The economical consequence
of these measurements is much larger than the few accredited measurements. So, the same requirements concerning the
uncertainty of measurement can be applied.
2 Policy guidance
The assessment for possible introduction of ‘Uncertainty of measurement’ into standards should be carried out by the Technical
Committees (TCs) (Working Group (WG), Subcommittee (SC), Joint WG, BT Task Forces (BTTF), etc.) before creation of a
new work item (WI).
The assessment should be conducted using the checklist provided in this document. CEN/BT WG 122 ‘Uncertainty of
measurement’ in researching this topic on behalf of CEN made some recommendations and proposals presented at the 53rd
CEN/BT meeting in Brussels, 2003-04-23/24.
The CEN/BT, noting the report (BT N 6831) and its recommendations, decided to ask CEN technical bodies and other relevant
bodies to be aware of the guidance and recommendations contained in that report.
The full report is available.
3 Checklist
Uncertainty of Measurements in Standard
Check-list steps
Questions
Yes
No
If ...then ...else
1
Do you intend to draft a standard for product specifications and measurement or for measuring methods ?
If
no
then go to 7 else go to 2
2
Could the absence of information on Uncertainty of measurement lead to possible disputes and negative consequences ?
Dealing with uncertainties in european standards