【国外标准】 Standard Specification for Maximum Permissible Thermal Residual Stress in Annealed Glass Laboratory Apparatus

This specification covers a limit for thermal residual stress in reusable annealed glass laboratory apparatus as determined by prescribed photoelastic measurement procedures. This specification recognizes that photoelastic measurements are proportional to the difference of the principal stresses. The stress limit shall be measured and calculated to meet the specified requirements.1.1 This specification covers a limit for thermal residual stress in reusable annealed glass laboratory apparatus as determined by prescribed photoelastic measurement procedures.1.2 In broad classification, the laboratory glassware items covered by this specification, but not limited to, are:beakers Imhoff conesbottles, aspirator impingersbottles, dropping jars, batterybottles, gas washing jars, bellbottles, infusion jars, chromatographybottles, milk test jars, cylindricalbottles, reagent joints, ball and socket or standard taperbottles, weighing manometersbulbs, absorption percolatorsbulbs, leveling pycnometersbulbs, sampling stopcocksburets tubes, centrifugecondensers tubes, chromatographycrystallizing dishes tubes, color comparison (turbidity)culture dishes tubes, combustion (ignition)custom apparatus tubes, connecting and adaptercylinders, graduated tubes, digestion and plain tubes, dryingdesiccators tubes, fermentationextraction tubes tubes, thistle (spray traps)flasks vapor trapsfritted ware viscometersfunnels watch glassesgenerators, Kipp  grinder, tissue  1.3 This specification recognizes that photoelastic measurements are proportional to the difference of the principal stresses. The limit imposed represents a safety factor to cover a situation in which one of the principal stresses may be larger than the apparent stress.1.4 This specification applies only to annealed glassware that is intended for sale as such. It excludes glassware that has been thermally tempered, ion-exchanged, or laminated with glass layers of differing expansion. The intent of this specification is to limit the residual stresses for safe consumer use in annealed glass, as it leaves the manufacturer.1.5 Stresses introduced by thermal expansion differences within the glassware are covered by this specification. Graded and glass-to-metal seals are excluded.1.6 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.