FAQ

What is Reference material related to?


 

Reference material RM

According in force guidance document a Reference material (RM) is a material answering the definition VIM-5.13 Material, sufficiently homogeneous and stable with reference to specified properties, which has been established to be fit for its intended use in measurement or in examination of nominal properties

Reference Material (RM):

ISO Guide 30 § 2.1 Material or substance one or more of whose property values are sufficiently homogeneous and well established to be used for the calibration of an apparatus, ...........

Certified reference material CRM

VIM 5.14 - reference material, accompanied by documentation issued by an authoritative body and providing one or more specified property values with associated uncertainties and traceabilities, using valid procedures

Certified Reference Material (CRM): Reference material, accompanied by a certificate, one or more of whose property values are certified by a procedure which establishes its traceability to an accurate realization of the unit in which the property values are expressed, and for which each certified value is accompanied by an uncertainty at a stated level of confidence.

Due to these definitions, it seems clearly that the wording sense "certified" is different from that handled by the ISO / IEC 17065 standard relative to products certification.

The simplest difference is in the level of reliability which we can grant them knowing that for the CRM, we try hard (every time it is feasible) to realise the metrological traceability of the values contained in the certificate in the basic units (in chemistry the mole, the kilogramme). But is not it also the case for the internal RM to the company, developed by the user?

However, we note that a certified reference material is before anything else a way(means) allowing to make sure the metrological measurement traceability of results produced in a laboratory in other values accepted as reference (by the industry branch, the users, the statutory regulatory authorities, etc.) and giving all the information necessary for its use: value, uncertainty associated with this value, corresponding units, number of uses, condition of preservation, etc.

Traceability evidence

According to the ISO 31 guide contents § 6, the certificate has to contain:

The values of the certified properties, each being accompanied with a determination of the uncertainty;

The methods used to obtain the values of the properties, in a very detailed way when the values depend on the method of measurement;

The duration of validity, where relevant

Measurement FAQ  


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