【国外标准】 Standard Specification for Laboratory Glass Volumetric Flasks

1.1 This specification covers requirements for glass volumetric flasks of precision and general-purpose grades suitable for laboratory purposes.1.1.1 Class A—Each flask of precision grade shall be marked with the letter “A” to signify compliance with applicable construction and accuracy requirements. Flasks may be marked with an identification number (serial number) at the option of the manufacturer.1.1.2 Class B—General purpose flasks are of the same basic design as Class A flasks. However, volumetric tolerances for Class B flasks shall be within twice the specified range allowed for Class A flasks. These flasks need not be marked with their class designation.NOTE 1: Specifications for micro volumetric flasks in sizes from 1 mL to 25 mL, inclusive, are given in Specification E237.NOTE 2: The Twelfth General (International) Conference on Weights and Measures redefined the litre as a “special name for the cubic decimetre,” but agreed to permit continuance of the terms litre, millilitre, and mL, except in association with measurements of the highest precision. For volumetric glassware the difference between the old and new meanings of litre is negligible. Therefore, either mL or cm3 may be marked on ware covered by this Specification.1.1.3 Special Size Flasks—Precision grade flasks may be manufactured with nominal capacities not listed in this standard. Such flasks shall be considered “Class A” flasks, provided they meet the accuracy tolerance of the next largest “Class A” flask appearing in Table 1 and comply with the marking requirements of 1.1.1.1.1.4 Wide-Mouth Flasks—Requirements for insertion of tablets or capsules for assay dilution and to accommodate access of larger diameter pipets require volumetric flasks with larger necks. These flasks appear in Table 2. These flasks shall conform to the marking requirements of 1.1.1. Additionally, the accuracy tolerance shall be marked on each “Class A” wide-mouth flask.1.1.5 Special Size Wide-Mouth Flasks—Precision grade wide-mouth flasks may be manufactured with nominal capacities not listed in this standard. Such flasks shall be considered “Class A” flasks provided they meet the accuracy tolerance of the next largest “Class A” wide-mouth flask appearing in Table 2 and the marking requirements of 1.1.4.1.2 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.