The Ionizing Surfaces method: An alternative approach for lightning protection design

Traditional methods of lightning protection are based on empirical experience. This observation leads to the implementation of a set of rules that apply with some degree of safety. They state that the zone of protection afforded by an air terminal as a Franklin rod is like a cone that provides a shielding angle of a fixed value. The protection is not complete and has a certain probability of failure on discharges of any size. As an alternative to traditional methods there is the Electrogeometric Model. This make a description of the physics of lightning in its last phase, known as the final jump, and is establish that its length depends on the magnitude of the lightning peak current. From its application to lightning protection is developed the Rolling Sphere Method as a tool in the design of protection systems, which is accepted by the IEC, IEEE, and NFPA standards. There are some problems with this method related to differentiated striking distances associated to a Franklin rods and the correspondents to others lightning conductors, and the difficulty in obtaining the protection zone which has a non trivial geometrical construction. In response to these facts, this paper present a proposal new design method called Ionizing Surfaces applicable to structures of any type, which uses the concept of the ionizing surface of each protective element, of structure and the environment for the design of lightning protection systems. For the application of the method, there are established the protection criteria needed for design of the protection system.