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7 Appendix
806 Exchange Unit
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31
Table 1 Typical measurement deviation of Metrohm exchange units
Cylinder volume max. systematic deviation
1 mL ± 3 µL
5 mL ± 15 µL
10 mL ± 20 µL
20 mL ± 30 µL
50 mL ± 50 µL
7.2.2 The ISO/EN/DIN standard 8655-3
The Metrohm exchange units fulfil the requirements of the ISO/EN/DIN
standard 8655-3 Volume measurement instruments with pistons –
Part 3: Piston burets. Metrohm guarantees that its exchange units are
in compliance with the following limit values at the time of shipment:
Table 2
Permissible limit values as per ISO/EN/DIN 8655-3
Cylinder
volume
max. systematic
measurement deviation
max. permissible
measurement deviation
1 mL ± 0.6 % ± 6 µL ± 0.1 % ± 1 µL
5 mL ± 0.3 % ± 15 µL ± 0.1 % ± 5 µL
10 mL ± 0.2 % ± 20 µL ± 0.07 % ± 7 µL
20 mL ± 0.2 % ± 40 µL ± 0.07 % ± 14 µL
50 mL ± 0.2 % ± 100 µL ± 0.05 % ± 25 µL
The Metrohm agents worldwide offer the possibility of on-site exchange
unit inspections and certifications with respect to accuracy. We recom-
mend that an accuracy inspection be performed when the dosing cylin-
ders and dosing pistons of an exchange unit are replaced.