These tests consist of condensation of evaporated, volatile components from interior equipment on vehicular window glass, the front windscreen. Determination of the fogging characteristics (liquid raw materials, paste and solid raw materials contained in the materials from which they are made) can be conducted using the following methods:
- fogging value – quotient of reflectometer 60° value of glass plate with fogging precipitate and reflectometer 60° value of the same glass plate without fogging precipitate
- fogging value – quotient of transmittance of a glass plate with fogging precipitate and transmittance of the same glass plate without fogging precipitate
- components condensation (G) – a difference of the weight of aluminum foil with and without fogging precipitate
The test sample is placed in a sealed beaker – the inside surface of the cooled beaker cover is either glass (for the photometric method) or aluminum foil (for the gravimetric method). The bottom of the beaker is placed in a controlled temperature oil bath for a specified period of time – typically 3 hours for the photometric method and 16 hours for the gravimetric method. For the photometric method, gloss readings of the glass cover before the test and after conditioning following the test are compared. For the gravimetric method, weights of the test sample and the aluminum foil before the test and immediately after the test are compared.