This International Standard specifies the test method for passenger car (ISO 3833:1977, 3.1.1) windscreen defrosting and demisting systems, when these are fitted.

This International Standard does not specify reference areas or levels of performance.

The test condition of −18 °C ± 3 °C specified for defrosting systems will meet the majority of cold climatic requirements.

The tests for demisting systems are conducted at a temperature of −3°C ± 1°C, since this is the practical minimum temperature at which mist, as defined in 3.7, can normally occur.