Glass durability tests

Glass durability tests There are two types of durability tests for glassware, viz. grain or powder tests and whole articles tests. 

A statement of standard tests for glass durability is given in Reference 14. G/ass Durability Testing... 

Caution is needed in applying the results of general chemical tests for glass durability across a wide spectrum of glass properties. Glass fibre strengths, for example, are sensitive to the physical, as well as the chemical, nature of the environment and should only be assessed by the direct strength measurements in conditions which closely approximate the final application situation . 

Jantzen, C. M. 1988. Prediction of glass durability as a function of glass composition and test conditions thermodynamics and kinetics. In Bickford, D. F., Boulos, E. N. et al. (eds) Advances in the Fusion of Glass Proceedings of the 1st International Conference on the Advances in the Fusion of Glass, 24.1-24.17. 

Fire and Wind Hazards. Weather resistance of roof coverings is not necessarily correlated to fire and wind resistance. Underwriters Laboratory and the Factory Mutual System test and rate fire and wind hazard resistance, and some durability tests. Organic felt or fiber glass mat base shingles are commonly manufactured to meet minimum UL requirements, which, in addition to minimum mass, require wind and fire resistance properties. 

Special durability tests have been made on optical glass. Qualitative gradings of durability were developed and listed in the glass catalogues. Quantifying such chemical attack is extremely difficult and has been the subject of international research. 

The choice of materials from which to make the holder is important. Materials must be durable enough to ensure satisfactory completion of the test. It is good practice to select very resistant materials for the test assembly. Insulating materials used are plastics, porcelain, Teflon, and glass. A phenohc plastic answers most purposes its principal hmitations are unsuitability for use at temperatures over I50°C (300°F) and lack of adequate resistance to concentrated alkalies. 

One of the most commonly used measures of durability, i.e. the loss of sodium from the glass, is important to the pharmaceutical and chemical industries, but other changes such as loss of surface quality, are of equal importance for optical and window glasses. The properties of a wide range of technical glasses are well catalogued but the data are often inadequate when considering a particular application and where possible nonstandard whole article tests are advisable. 

ASTM 1994. Standard Test Methods for Determining Chemical Durability of Nuclear Waste Glasses The Product Consistency Test (PCT). Standard Cl285-94. ASTM, Philadelphia. 

Finally, the apparent normalized release rate of Si (r(Si)norm) in the HT samples was compared to the one obtained for the standard HLW glass SON68 under the same conditions of corrosion. Of the 23 HT samples tested, 6 samples exhibit r(Si)norm < SON68, thus presenting a highly favourable dynamic picture with respect to their long-term durability. 

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