3. Environmental impact on comfort

3.1 Air velocities and cladding properties

Thermal and vapor permeation resistances are actually affected by the "pumping" effects of the wearer's movements, which encourage air to enter the garment, and by wind-driven air movements.

This reduces their convective properties, as well as their resistance to water vapour transfer.

The following paragraphs describe the calculation of the decrease in these resistances in accordance with ISO 9920, the genesis of which is explained in articles...