A.3 Determination of errors of indication
A.3.1
The thermometers must be examined for compliance with the provisions of Clause 8 with regard to maximum permissible errors. This examination is performed by comparing the test thermometers with standard thermometers (A.1.2.2.2) in well-stirred water baths (A.1.2.2.1).
A.3.2
The thermometers must be checked at a minimum of two temperatures spaced apart (test temperatures) in the to range.
A.3.3
Control at a given temperature.
A.3.3.1
Using, if necessary, the centrifuge (A.1.2.2.4), the mercury column in the thermometers under examination is driven down to at least below the test temperature.
A.3.3.2
The thermometers are placed in the water bath once the bath has been brought to the test temperature.
A.3.3.3
When the temperature of the water bath is again sufficiently constant (see A.1.2.2.1) and at least 20 seconds have elapsed, the bath temperature () is measured with the standard thermometers, whereupon the thermometers under examination are removed from the bath.
When measuring temperature, the corrections to the standard thermometer indications must be taken into account (A.1.2.2.2).
A.3.3.4
The thermometer indications are observed when they have reached ambient temperature ( to ). The differences between the indications and are the thermometer errors at the test temperature.