New guidelines regarding the positioning of protective air terminations on structures using e-field modelling techniques

An important consideration in the design of any air termination system is the maximum distance at which the terminations can be placed from the “vulnerable points” on structures, i.e., typically those points that create the highest degree of electric field intensification. This paper extends a previous, preliminary analysis of the problem in three significant ways. Firstly, the height range of the air terminations has been extended by a factor of 4 with a series of additional calculations. Secondly, account is taken of the material of construction of the building on which the air terminations are installed. Thirdly, and most importantly, a field study has been carried out in a high-lightning area as real check on the model results. All of the results are compared and some quantitative guidelines are provided for the maximum distance at which air terminations should be installed from the vulnerable points of structures.