Hohenstein Quality Label: Hohenstein Performance Index

The thermoregulation model of human skin (or skin model) is a measuring device that simulates both dry and sweating human skin. The skin model is used to determine material-specific, thermophysiological parameters of textiles as a surface material (according to DIN EN ISO 11092).

When determining the water vapor transmission resistance (breathability), we describe the wearing condition in which there is a constant flow of moisture from the wearer's body to the environment, over time. Moisture is released from the skin in the form of water vapor. However, similar to thermal insulation, the breathability of a textile depends on the thickness of the textile. Therefore, the water vapor transmission index puts breathability and thermal insulation in relation to each other, so that a statement can be made about the water vapor transport capacity of the textile, independent of the material thickness.

For the evaluation of product performance, especially of base layer garments (textiles worn close to the skin), sweat management is of great importance.

When determining the buffering effect of liquid sweat and sweat transport (DIN EN 16422), we describe the condition in which the wearer sweats so much that liquid sweat occurs. In general, base layer materials should be able to rapidly absorb the sweat produced by the wearer and dissipate it to the environment.

Air permeability is determined (with the DIN EN ISO 9237 standard) by clamping a flat material sample in the test instrument and setting the air flow to a specified differential pressure. The air velocity is the volume of air - per unit of time and area - that flows through the sample.

Textiles labeled as waterproof should allow NO water to pass through. Even after extended time in the rain, the wearer should remain completely dry under a waterproof outer shell garment. The hydrostatic pressure test (DIN EN ISO 20811) proves the resistance of textiles to water penetration.

Textiles that are water-repellent remain dry on the outside. The fabric does not absorb water. Rain or other liquids bead off the surface. This effect is maintained if the fabric is exposed to rain for a long period of time, but water can penetrate between the individual fibers under continuous pressure. Water does not penetrate the fibers (the fabric remains dry), but moisture can push past the fibers and into the interior. The water-repellent properties are tested with DIN EN 29865 using a Bundesmann rain-shower tester.