scope:

This International Standard specifies: a) method for determining the hydrolytic resistance of glass grains at 98 ° C. The resistance is measured and expressed by the volume of acid required for titration of the alkali extracted from the unit mass of glass, and may also be expressed by the amount of sodium oxide equivalent to this volume of acid; b) a classification of glass according to the hydrolytic resistance determined by the method of this International Standard. This International Standard is intended for use on the less resistant types of glass. For the more resistant glasses the method specified in ISO 720 is preferable.