The behaviour of glass in domestic dishwashers: a comparison between standard multicycling test and rapid immersion test

The penetration of dishwashers in families attitudes has favoured the development of test procedures with the aim of evaluating the mechanical and chemical resistance of foodware exposed to dishwashing. The Technical Committee CEN/TC194/WG3 has issued a refeience standard test registered as ENV 12875/part 1, that describes the characteristics of the dishwasher, the type of detergent, the washing cycle and the duration. Since this test requires a considerable amount of time to complete a programme of 500/1000 cycles, in this study we have considered the pertormance of a rapid immersion test to be possibly used as an alternative to the reference test. The tests were carried out on several types of glass (lead crystal, crystallin, soda-lime, art glass) using the high alkaline standard detergent of type A, containing phosphate. The defects arising from the multicycling test are essentially reluted to the glass composition and the forming process. In the immersion test defects are of a different nature, often localized within small spots, being mostly related to the corrosion process, which is due to the strongly alkaline attack induced by the detergent. In conclusion, the rapid immersion test can only give a general prediction about the resistance of glass against the alkaline attack, but no correlation can be established with the reference multicycling test, at least when the standard detergent of type A is used.