ISO 7884-4:1987 Glass viscosity and viscosity fixed points Part 4: Determination of viscosity by bending beam method The standard specifies a method for determining the viscosity of Glass by bending beam method. Bending beam method is a method for determining the viscosity of Glass samples by measuring the degree to which they are bent under force during heating. The standard describes in detail the test equipment, specimen prepative, experimental conditions and data processing requirements to ensure accuracy and repeatability of results. The viscosity properties of Glass at high temperatures can be obtained by bending beam method, providing a scientific basis for the processing, molding and its hot working performance of Glass. This method is widely used in the Glass industry and research to help optimize the production process of Glass and improve product mass.