BS 7034-5-1988 Glass viscosity and determination of viscosity fixed points. Part 5: Method of measuring working point using a mandrel-free Viscosity meter is a standard developed by the British Standards Institution, which specifies the method of measuring the working point of Glass using a mandrel-free Viscosity meter. Working point refers to the state in which Glass reaches a specific viscosity during processing and is an important parameter in the glass production process. This standard applies to the viscosity measurement of high temperature glass melts, and the viscosity characteristics of Glass are determined by the sedimentation rate of the mandrel-free Viscosity meter. Measurement principles, instrument requirements, operation steps and result analysis provide a scientific basis for Glass production, R & D and quality control.