There are local practices, traditions, and a variety of standards. For a list of related standards, see Reference Material.
Lightning density varies a lot based on geographic factors. The following figure illustrates the differences in lightning density in different areas. The figure shows the lighting strikes per square kilometer per year.
Lightning density is low to moderate around the poles and increases from moderate to high towards the equator.
Geographical variation can be substantial:
- In the northern countries, lightning strike density is low: annually ~1 strike/km2 (10.8 ft2), and the practices are less regulated.
- In tropical countries, lightning density is high. Local practices may contradict major international standards in some aspects. Follow the local code if that is a contractual requirement and it does not pose a safety hazard. An example of a safety hazard is, for example, substituting several standard air terminals with a single “special” device that is supposed to have an extraordinary large protection range.