Glass articles that may be subjected to significant differences in temperature during their normal use should be tested for thermal shock resistance to ensure the product is fit for the intended purpose. For example, the shock of taking a casserole dish from a hot oven and placing it on a cool worktop may be enough to cause it to break.
Thermal shock testing involves the cyclic testing of a products from a hot temperature to cold temperature until failure in order to calculate the thermal shock endurance, or resistance, for that product.
Thermal Shock Methods
Testing can be provided to Veriquality recommendations, client own in-house test-methods or to a range of international standards, including:
- ASTM C149-86 Standard Test Method for Thermal Shock Resistance of Glass Containers;
- BS EN ISO 7459 Glass containers. Thermal shock resistance and thermal shock endurance. Test methods.
- BS EN 1183:1997 Materials and articles in contact with foodstuffs. Test methods for thermal shock and thermal shock endurance
Glass Products Tested
Thermal shock testing is relevant for a wide range of glass products and items, examples include:
- Bottles and jars;
- Cookware and kitchenware;
- Toiletry and cosmetic containers;
- Domestic wares, such as bowls, vases, glass drinking vessels, latte glasses and mugs;
- Cafetieres ('French Press', coffee press, afetière à piston);
- Candle holders, candle jars and hurricane lamps;
- Technical, industrial and pharmaceutical glasses.