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ensure that the measurement process “does produce” correct results.
This type of demand also applies to testing and calibration laboratories.
The ISO 10012 norm, “System of management of the
measurement – requirements for the measurement equipments and
processes” introduces the following demand:
If the result of a metrological verification prior to any adjustment
or repair indicates that the measuring equipment did not meet the
metrological requirement such that the correctness of the measurement
results may have been compromised, the equipment user shall
determine the potential consequences and take any necessary action.
This can involve re-examination of product produced using
measurements taken with the nonconforming measuring equipment.
These measures can have significant technical and financial
implications for a firm or a laboratory. For firms there are two
immediate consequences of this requirement:
– the need to have the intervals of calibration of the instruments
under control;
– the need to set up methods of monitoring the measuring
instruments.
The determination of the calibration intervals and their
modification, plus the setting up of the methods of monitoring, make
it possible to minimize the risk, or at least to control it.
A selection of the instruments to be monitored will have to be
made when setting up the monitoring methods. Those instruments that
are especially critical from an economic point of view or for security
reasons should be examined first.
The ISO 10012 international written standard requires the
organization to specify which measurement processes should comply
with the measures stated in this international standard. It is advisable
to take into account the risks and consequences of not satisfying the
metrological requirements when the limits within which a standard
has to be complied with have been defined.
Methods for monitoring the instruments in use – general
criteria
These methods should satisfy some criteria in order to work
efficiently and be applicable when the instruments in use are
monitored:
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