A.6 Testing the materials
Because the examination which pertains to compliance with the provisions of Clause 4 (Materials) cannot be conducted on the thermometers themselves, the manufacturer of clinical thermometers (mercury-in-glass, with maximum device) must prove to the verifying authorities that the materials used meet the requirements of Clause 4.
When considering the test methods to be used in case of doubt, the following provisions should be taken into account:
A.6.1
Because the value of the depression of zero depends strongly on the conditions under which the test is performed, the method outlined in Annex B should be used to determine the depression of zero (4.1).
A.6.2
The provisions concerning the analysis of the glass in accordance with ISO Recommendation R 719-1968 (4.2) must be taken from that Recommendation.
A.6.3
Method for testing the dimensional stability of scale-bearing strips made from materials other than either opaline or metal (4.3)
A.6.3.1
The aforementioned tests are carried out on at least 5 scale-bearing strips marked with graduation lines and numbering (2.2) and manufactured from the material being tested.
A.6.3.2
The distance between the graduation lines which correspond to and must be measured with a maximum uncertainty of measurement of (measured value ).
A.6.3.3
The scale-bearing strips are then kept at a temperature of for 7 days.
A.6.3.4
After they have been cooled to ambient temperature ( to ), the distance between the graduation lines which correspond to and is measured once more (measured value ).
A.6.3.5
The scale-bearing strip material tested is considered equivalent to opaline or metal with respect to its dimensional stability if: