What is ISO 720 about?
More resistance glass has become useful in a wide variety of industries and applications, because of its physical and chemical properties. ISO 720 is intended for use on the more resistant types of glass, e.g., borosilicate glass.
ISO 720 specifies the method for determining the hydrolytic resistance of glass grains at 121 °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 can also be expressed by the amount of sodium oxide equivalent to this volume of acid.
ISO 720 also describes the classification of glass according to the hydrolytic resistance determined by the method of this document.
ISO 720 also specifies permissible range of the values obtained and the limit values in the hydrolytic resistance grain test. The principle, reagents, apparatus and the procedure are specified in this document.
NOTE- The test method shall not be applied to glasses with extreme low alkaline contents or that are essentially free of alkaline species.
Who is ISO 720 for?
ISO 720 on glass testing is useful for:
- Manufacturers of glass and glazed products
- Construction industries
- Medical sectors
- Glass industries
- Chemical laboratories
- Regulatory and Certification bodies
Why should you use ISO 720?
Borosilicate glass can withstand corrosion and breaking when exposed to acidic environments. More resistant types of glasses or borosilicate glasses are produced on a large scale and used for high-quality beverage glassware, drinking glasses, and blood processing equipment for medical and pharmaceutical use.
ISO 720 provides you with test procedure called a hydrolytic resistance grain test to be used on glasses for determining and assessing the density of glass. The outcome of such a test may be useful in increasing the direct and extended fields of application for the glass product range.
ISO 720 describes the classification method of glass according to the consumption of acid and its equivalent of alkali [sodium oxide (Na2O)], when tested by the method specified in this docment.
Compliance with ISO 720, will help you lengthen life span of your glass products and demonstrate reliability and credibility for your products with the regulatory marking. Also, it will help in prevention of waste.
What’s changed since the last update?
BS ISO 720:2020 supersedes BS ISO 720:1985. BS ISO 720:2020 includes some technical changes with respect to BS ISO 720:1985. These include:
- More precise definition of the field of application by means of glass types was added
- Wherever possible a harmonization with the identical paragraphs in the European Pharmacopoeia, chapter 3.2.1, and the USP, chapter 660, was established to simplify the application in the laboratories globally. This concerns, e.g. sample size, mesh size
- The process of autoclaving was adapted to the requirements of the European Pharmacopoeia, chapter 3.2.1, which will ease the application of this document
- The usage of acetone was restricted to always fresh, new acetone, since re-usage might lead to deviating test results
