5.1.7 Collection areas

The collection areas for the structure are determined once all conductors have been fully recorded and described. The areas A_D (direct lightning strike), A_M (nearby lightning strikes) and, if applicable, A_DJ (connected structures / nodes) must be taken into account.
The collection areas A_D, A_M and A_DJ are calculated as per IEC 62305-2. Details on this can be found in the chapters 3.3.3.1, 3.3.3.2 and 3.3.3.3.

Simple vs. complex structures
There are two options for determining A_D and A_M:

• Simple structures (Figure 5.1.7.1): Entering the length, width and height will suffice. DEHNrisk automatically calculates the equivalent collection areas A_D and A_M from this.
• Complex structures: The areas can be entered manually or transferred from a drawing in DEHNplan (Figure 5.1.7.2). The prerequisite is that DEHNplan is installed on the computer. Each DEHNrisk licence includes a 'DEHNplan light' version, which can be used to create or import building drawings and calculate surface areas. Lightning protection planning is not possible with this licence.