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 cones

bottles, aspirator

impingers

bottles, dropping

jars, battery

bottles, gas washing

jars, bell

bottles, infusion

jars, chromatography

bottles, milk test

jars, cylindrical

bottles, reagent

joints, ball and socket or standard taper

bottles, weighing

manometers

bulbs, absorption

percolators

bulbs, leveling

pycnometers

bulbs, sampling

stopcocks

burets

tubes, centrifuge

condensers

tubes, chromatography

crystallizing dishes

tubes, color comparison (turbidity)

culture dishes

tubes, combustion (ignition)

custom apparatus

tubes, connecting and adapter

cylinders, graduated

tubes, digestion

 and plain

tubes, drying

desiccators

tubes, fermentation

extraction tubes

tubes, thistle (spray traps)

flasks

vapor traps

fritted ware

viscometers

funnels

watch glasses

generators, 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.