The article by Prof. Eduard M. Bazelyan on the issues of selecting LPS for the roof lightning protection is published at our website. This article is very popular because it provides the comparison of lightning arrester types and description of their pros and cons, while at the same time, possible solutions for efficiency issues are offered.
The first and second parts of the article describe the issue of choosing the lightning arrester installation site. Due to evident factors, the installation of a standalone lightning arrester near the high-rise building is unreasonable. Does it mean that the LPS should be placed on the roof? Where exactly then: in the middle or at the edge? Do the roof dimensions matter? What about multi-purpose flat roofing? Unfortunately, recommendations provided in the regulatory documents (IEC 62305 and SO 153-34.21.122-2003) are not at all trustworthy. The calculations provided herein confirm the fact of insufficient scientific elaboration of the issue of efficiency of the lightning arrester installed on a building roof.
Then, an issue of using the lightning grid and doubtful recommendations for its use stated in RD 34.21.122-87 is raised. When can the grid be used and when it can't? The answer is given by Eduard in the third part of the article.
The fourth and fifth parts of the article describe the European experience of operation of wire LPS and provide comparison with low lightning rods. Moreover, the calculation of dependencies between the lightning breakthrough probability to the building roof and the height of installation of a closed wire lightning arrester relative to the ground in external offsets of the wire from the roof edge of 1 and 2 m are provided herein. In the fifth part, the professor notes the challenges associated with installation of multiple LPS, namely the need to use welded connections, according to RD 34.21.122-87. See the fifth part of the article to learn how to bypass this requirement but do not reduce the protection degree.The final part provides the comparison of lightning arrester types noting clear advantages of a certain type of lightning arresters.
Read more in «"Lightning Arresters on the Roof (Roof Lightning Protection)"»
E. M. Bazelyan, Dr. Sc. (Eng.), Professor;
Krzhizhanovsky Energy Institute, Moscow;
recognized Russian Expert in Grounding and Lightning Protection
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