TABLE OF CONTENTS Air terminations are fixed points for likely lightning strikes used to avoid uncontrolled strikes and to prevent the volume to be protected from direct strikes. Air terminations comprise air-termination rods and air-termination wires. The latter may be laid as a meshed network. The location of air terminations is usually defined by the 'rolling sphere' method (Figures 4.1.3.1.2 f a, b and c). This means that a certain radius of rolling sphere will be assigned to every protection level in accordance with DIN ENV 61024-1 (Table 4.1.1 b).
Finally, air terminations form a system of protection for structures on the roof (such as ventilators and air-conditioning systems). On flat roofs 'partly isolated' lightning protection systems are usually installed as described in chapter 4.1.3. This air-termination system is spatially separated from lightning protection zone 1, so that there is a lightning protection zone 0 B between the air-termination system and lightning protection zone 1 (Figures 4.1.3.1.2 b and d). For smaller roof structures this protection can be achieved by individual or a combination of several air termination rods. For larger roof structures protection by means of air termination rods is not often possible as the rods would be too high and thus there is danger of leaning. As an alternative an isolated air termination is the best solution. The distance between air terminations and structures on the roof must at least coniform to the calculated safety distance.
Air-termination networks must form a protective volume including all structures on...
