Overview
EN ISO 2747:2022 (identical to ISO 2747:1998) specifies a laboratory method for determining the resistance to thermal shock of vitreous and porcelain enamelled cooking utensils and similar articles. The standard defines a repeatable procedure of successive thermal shock tests - heating the utensil to a defined temperature and then chilling it with cold water - to identify the temperature at which the enamel first shows visible damage (chipping or tension cracks).
Key topics and technical requirements
- Scope and purpose: Measure behaviour of enamelled cookware under sudden temperature changes to quantify thermal shock resistance.
- Definitions: Includes terms such as thermal shock test, thermal shock temperature, thermal shock resistance, and damage (visible at 250 mm or revealed by coloured penetrating fluids).
- Test principle: Series of single thermal shock cycles with a 20 °C increase between successive tests until damage occurs.
- Temperatures:
- First thermal shock temperature: 200 °C ± 5 °C.
- Subsequent tests: increase by 20 °C increments (e.g., 220 °C, 240 °C, …).
- Chilling water temperature: 20 °C ± 1 °C.
- Specimen considered damaged when first visible chipping or tension cracks appear.
- Specimens and sampling:
- Use actual utensils without modification.
- At least three specimens representative of the lot.
- Apparatus:
- Controlled electric hot-plate sized and powered per the standard (tabled diameters and outputs).
- Fast-response temperature measuring device (±2 °C), thermometer, stopwatch, water receptacle, drying materials.
- Procedure highlights:
- Fill specimen with water to 30 mm (if possible), heat to target temperature, pour in cold water in one pouring, remove after ~5 s, then fully immerse to cool rapidly.
- Inspect for damage when specimen returns to room temperature (23 °C ± 1 °C).
- Results and reporting:
- Report individual and average thermal shock temperatures and calculated average thermal shock resistance (average temperature minus 20 °C).
- Include specimen description, sampling plan, hot-plate details, type of damage (photograph if necessary), and any deviations (e.g., water depth).
Applications and users
- Manufacturers of enamelled cookware and kitchenware for product development and quality control.
- Independent test laboratories performing conformity, durability and safety testing.
- Certification bodies and regulatory organizations assessing cookware performance.
- R&D teams optimizing enamel formulations, enamel thickness, and substrate/enamel compatibility to improve thermal performance.
Related standards
- Adopted by CEN as EN ISO 2747:2022 (no technical changes to ISO 2747:1998).
- Prepared by ISO/TC 107 and adopted by CEN/TC 262 - useful context for traceability and harmonized European implementation.
Keywords: EN ISO 2747:2022, thermal shock resistance, enamelled cooking utensils, vitreous and porcelain enamels, thermal shock test, cookware testing.
