The protection of structures against lightning

The British Standards Institution has just issued a set of Recommendations on this subject, which is the first authoritative general guidance that has been made available to the public in this country since the Report of the Lightning Rod Conference in 1881 and its amendment by the Lightning Research Committee in 1905. These new Recommendations have been adopted and published by the Codes of Practice Committee for Civil Engineering Works and Building formed under the aegis of the Ministry of Works and Planning. The Code of Practice should be referred to because in addition to the Recommendations it contains appendices in which comment is made on some of the new features dealt with, and which this paper to some extent amplifies. This paper does not deal with the protection of ships, aircraft or electric supply and telephone wires, but it attempts to throw light upon the problems connected with the protection of modern steel-framed and ferro-concrete structures. The need for protection is discussed and a rough attempt is made to assess the risk attached to any structure in any part of the world. The zone of protection receives attention and the presence of metal in the buildings is debated. The needs of structures which are very vulnerable to lightning, and of others which present difficult problems, are discussed. The components of a protective system, their materials and dimensions, together with their cost are referred to, and finally inspection, testing and records are dealt with.