"EN 13595 Parts 1-4— Protective clothing for professional motorcyclists— Jackets, trousers and one-piece or divided suits," PVA Technical File Services. [link]

DIAGRAM OF ZONE POSITIONS ON A SUIT. DRAWN FROM A SUIT LAID OUT FLAT, SLIGHTLY SIMPLIFIED.

Part 1 also covers design principles and explains the controversial “zoning” principle for motorcycle clothing where the protective performances of different parts of the garment are proportionate to the severity of the forces they will be expected to withstand in an impact with and slide along a hard, abrasive road surface. For example, the various limb joints and the buttocks are expected to provide a significantly higher level of impact abrasion, impact cut and burst resistance because these are the areas of a garment which are most at risk of heavy and prolonged contact with the road. Figure 1 explains the zoning principle.