Standards Development

Scope

This International Standard provides methods for the testing, calibration and use of volumetric instruments made from glass and plastic in order to obtain the best accuracy in use.

NOTE Testing is the process by which the conformity of the individual volumetric instrument with the appropriate standard is determined, culminating in the determination of its error of measurement at one or more points.

The International Standards for the individual volumetric instruments include clauses on the definition of capacity; these clauses describe the method of manipulation in sufficient detail to define the capacity without ambiguity. This International Standard contains supplementary information.

The procedures are applicable to volumetric instruments with nominal capacities in the range of 0,1 ml to 10 000 ml. These include: single-volume pipettes (see ISO 648) without subdivisions; graduated measuring pipettes and dilution pipettes, with partial or complete subdivisions (see ISO 835); burettes (see ISO 385); volumetric flasks (see ISO 1042); and graduated measuring cylinders (see ISO 4788). The procedures are not recommended for testing of volumetric instruments with capacities below 0,1 ml such as micro-glassware.

This International Standard does not deal specifically with pyknometers as specified in ISO 3507. However, the procedures specified below for the determination of volume of glassware can, for the most part, also be followed for the calibration of pyknometers.

Purpose

The proposed work item deals with the revision of a generally used international standard (ISO 4787). The work is based on preliminary work that has already been done in ISO/TC 48/WG 7.

The technology and equipment used to determine volume has developed during the last 10 years, also laboratories are now more aware of the importance of accuracy and uncertainty in their measurements and therefore it was decided to revise ISO 4787:2010 and include the following changes:

a) plastic ware is included

b) new information on meniscus adjustment of convex meniscus;

c) improved figures for meniscus adjustment;

d) table 1 was improved;

e) new table 2 for minimum requirements for the measurement devices;

f) new test room ambient conditions;

g) new information regarding repeatability and uncertainty added in annex E.

Consider the following: Is there a verified market need for the proposal? What problem does this standard solve? What value will the document bring to end-users? See Annex C of the ISO/IEC Directives part 1 for more information. See the following guidance on justification statements on ISO Connect: https://connect.iso.org/pages/viewpage.action?pageId=27590861