EN 342 sets the requirements for clothing intended for work below −5 °C. It covers both complete ensembles (jacket plus trousers, or a coverall) and single garments.
The marking parameters
- Icler / Icle
- Resultant thermal insulation in m²·K/W — the key figure; the higher the warmer
- AP
- Air permeability class from 1 to 3; class 3 is the most windproof
- WP
- Water penetration resistance — optional, class 1 or 2
The working-time table
The most useful part of EN 342 is the table in the garment's instructions: it shows how long the wearer can work at a given temperature and activity level. Light activity (standing, observing) allows far less time than heavy physical work, because the body generates less heat of its own.
The layering principle
EN 342 clothing is always part of a system. Insulation is measured together with a base layer, so wearing a cotton T-shirt instead of a synthetic base layer sharply reduces the real insulation. Cotton holds sweat, and wet cotton loses heat.