08 TECHNICAL INFORMATION | PRODUCT-SPECIFIC SECTION
VOLUMETRIC PRODUCTS
DURAN® volumetric products have closely calibrated scales that permit very accurate determination and measurement of volumes. They are available in two accuracy classes: class A/AS and class B. The two classes differ in the accuracy of measurement with class A being the highest accuracy, and class B is approximately half that of class A. Class AS has the same tolerances as class A, but is designed to permit more rapid outflow; it is applicable to burettes and pipettes.
Precise differentiation
The volumetric instruments are essentially available in the accuracy classes A, AS and B.
Accuracy class A: Denotes the accuracy limit in accordance with DIN and ISO and is therefore the most accurate class. A conformity mark is printed on volumetric instruments in class A to indicate they satisfy the requirements of the German weights and measures regulation and the applicable standards.
Tolerance indication with a volumetric flask in accuracy class A ( a ) with a tolerance of ± 0.15 ml ( )
Accuracy class AS: Denotes pipettes and burettes in accuracy class A with a rapid discharge (S). The waiting time is significantly less than with class A.
Accuracy class B: Denotes an accuracy limit which is twice as large as class A.
Tolerance indication with a volumetric flask in accuracy class B ( ) with a tolerance of ± 0.3 ml ( )
Certificates
Conformity mark – Volumetric instruments that comply with the requirements of applicable standards (e.g. the German weights and measures regulation) are labelled accordingly with “DE-M”. The “DE-M 15” mark is made up of the elements DE (which stands for “Deutschland”), M (which stands for “Metrologie” (metrology), and the year number 15 (2015, the year in which the measuring instrument was labelled). Batch certificate – Volumetric flasks and measuring and mixing cylinders with a batch number and accuracy class A are supplied with a batch certificate. This certificate documents the mean value obtained from measuring the batch in question, the standard deviation and the day of issue. The batch certificates can also be retrieved online. The batch number consists of four digits, e.g.: . The first two numbers specify the production year, and the following two numbers specify the batch. Individual certificate – Volumetric flasks which, in addition to the batch number, are numbered individually, are supplied with an individual certificate. The individual number is permanently laser-etched onto the base of the volumetric flask and is entered on the corresponding certificate. The volume measured for the corresponding volumetric flask, the measurement uncertainty and the day of issue are documented on this certificate. It is also possible to retrieve a batch certificate online. The individual number is a consecutive number and comprises three letters and a four digit number, for example: AAA-0001.
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