Their number is limited to 4 in a chamber with a volume of 0,4 m3.They are suspended inside the chamber (or placed on grids); it would be best if they were not on the same plane, but at different heights (for example +/- 20 cm of the chamber mid-height).Care must be taken so that no external trickling occurs on a specimen. Harnesses must observe the recommended lower point.Two photographs illustrating the position of specimens and harnesses must be shown on the test report. The validity of the polluting solution must not exceed 6 months