Background of Volume Standards

Occasionally you may see references to Federal Specification numbers. For example, the Federal Specification number NNN - C 940-C is for graduated cylinders. All Federal Specification numbers are no longer being updated, and these specifications are being superseded by those established by the ASTM. The preceding number for graduated cylinders is now under the specifications of ASTM 1272-89. All ASTM documents are identified by a designation number. If there 

Burette 0.03 mL Serological pipette (only Class B lower) 

All manufacturers abide by the standards set by these organizations. Therefore with the exception of quality and control, one manufacturer s volumetric ware (of comparable type) should not be more accurate than another manufacturer s. It is important to keep these guidelines in mind so that ASTM standards are not allowed to be used as marketing hype. 

Do not let the designation Class A mean more than it was meant to. Class A can only mean that it is the best tolerance readily available for that specific type of volumetric ware. Class A volumetric ware is not consistent across volumetric ware type. For example, a Class A volumetric pipette does not have the same degree of tolerance as a Class A measuring pipette. Equally, a Class A graduated cylinder does not have the same degree of tolerance as a Class A volumetric flask. See Table 2.6 for a representative cross comparison of Class A tolerances. 

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