ALL ABOUT VOLUMETRIC WARES

Volumetric laboratory glassware is available in three main calibration classes: Class AS, Class A and Class B.

Below is a quick guide to what each class means so you can better decide if they are suitable for your application.

The accuracy of each class is measured in terms of tolerance (tolerance is the accuracy in a measurement made with the glassware).

Class A and Class AS volumetric glassware have a lower tolerance than Class B and therefore can be considered more reliable and more. Further, Class AS corresponds to ASTM tolerances and it is slightly more accurate than Class A that corresponds to DIN/ISO Standards.

Class A & AS Volumetric Ware - Calibrated according to DIN/ISO & ASTM Standards.

One-Mark Volumetric Ware: Volumetric Flask and Volumetric Pipettes

Multi-Mark Volumetric Ware: Graduated Cylinders, Burettes and Serological/Mohr Pipettes

It is important to note the tolerances for Multi-mark volumetric ware purchased from a reputed manufacturer or a dealer will always be uniform at more than one calibration point for any product.

For Eg.: Class A measuring Cylinder 250 ml with a Permissible variation of +/- 1ml will have same permissible variation even at 100 ml for the same cylinder.

Class B: Calibrated according to DIN/ISO & ASTM Standards.

Volumetric instruments of class B are within twice the error limits when compared to class A/AS as defined by DIN/ISO & ASTM standards.

Example for 250ml CLASS B Glass Cylinder = Permissible variation error @ 250ml +/- 2.0ml

Certification:

Each glass volumetric measuring instrument in Class AS and Class A is individually or batch Certified. Computer-controlled systems ensure maximum precision in a fully automated production line.

Each glass volumetric measuring instrument in Class B is batch (not individually) calibrated. Computer-controlled systems ensure maximum precision for the batch of glass instruments in that particular production line.

Types of calibration:

'TC, In':

The contained quantity of liquid corresponds exactly to the capacity indicated on the instrument (eg., graduated cylinders and volumetric flasks).

'TD, Ex':

The delivered quantity of liquid corresponds exactly to the capacity indicated on the instrument (eg., pipettes and burettes).

Heating of volumetric instruments:

All glass volumetric instruments can be heated up to 250 ºC in a dry box or sterilizer without having to worry about a change in volume. Use only gradual heating and cooling. Abrupt temperature changes can cause thermal stress and may result in glass breakage.

Glassware for Research Labs, Pharmaceutical Companies.

When purchasing measuring and volumetric glassware for applications where high accuracy is required, Class A and Class AS stamped glassware is always recommended.