6.3.1 Air-termination systems for buildings with gable roofs

The purpose of the air-termination system is to specifically define preferred points of strike for lightning and to safely divert the lightning currents into the building's earthing system.
Certain areas of a building are particularly vulnerable to lightning strikes due to their exposed location. These include in particular:

• Gable tops
• Chimneys
• Roof ridges and crests
• Gable and eave edges
• Parapets
• Other protruding roof-mounted structures

These points must be equipped with suitable air-termination systems to ensure effective capture and safe dissipation of lightning currents.
In buildings with gabled roofs, a meshed network of air-termination conductors is usually installed on the roof surface. The size of the mesh depends on the selected lightning protection class. For example, the recommended mesh size is 15 m × 15 m for buildings in lightning protection class III (Figure 6.3.1.1).