Best Measurement Capability (BMC) Change in Terminology to Calibration and Measurement Capability (CMC)

The BIPM and ILAC has confirmed to change BMC to CMC, which are actually identical in meaning; and the HKAS also followed this change this year. See below for details.

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Best Measurement Capability (BMC)

Change in Terminology to

Calibration and Measurement Capability (CMC)

Metrological traceability is disseminated to the market by Accredited Laboratories

under the ILAC MRA and by National Metrology Institutes under the CIPM MRA.

This provides reliability without frontiers for measurements across the world.

The capabilities provided by accredited calibration laboratories have in the past been

described by the Best Measurement Capability (BMC) which expresses the lowest

uncertainty of measurement that could be achieved during a calibration. This

terminology has been widespread in accreditation around the world.

The National Metrology Institutes (NMIs) have had a similar description of the

services provided to their clients. Within the NMI community the term has been

Calibration and Measurement Capability (CMC). The BIPM and the Regional

Metrology Organisations (RMOs) have in cooperation with ILAC and the Regional

Accreditation Bodies (RABs) investigated the difference in terminology and have

arrived at the following conclusion:

"In the context of the CIPM MRA and the ILAC Arrangement, and in

relation to the CIPM-ILAC Common Statement, the following

shared definition is agreed :

a CMC is a calibration and measurement capability available to

customers under normal conditions:

(a) as published in the BIPM key comparison database (KCDB)

of the CIPM MRA; or

(b) as described in the laboratory’s scope of accreditation

granted by a signatory to the ILAC Arrangement. "

In pursuit of harmony and co-operation between the communities; ILAC has decided

to make a change in the terminology used and in the future the BMC will be named

as the CMC. The intention is to achieve harmonisation of terminology in the

dissemination of metrological traceability worldwide regardless of source.

The EA Accreditation Bodies will implement the change in terminology by 31

December 2010.

As a consequence of the CIPM-ILAC Common Statement, during this transition

period, reference to BMC and to CMC should be considered equal by laboratories,

their clients, the market and regulators.

EA Laboratory Committee

24 September 2009