Lightning Risk Assessment and Management as per IS IEC 62305-2
if required at what level. Close liaison between the architect, the builder, the lightning protective system engineer, and the appropriate authorities are required to ensure proper design of Lightning Protection.Structures with inherent explosive risks; for example, explosives factories, stores and dumps and fuel tanks : usually need the highest possible class of lightning protective system.
In many cases, the need for protection may be self evident, for example:
- Where large numbers of people congregate:
- Where essential public services are concerned;
- Where the area is one in which lightning strokes are prevalent;
- Where there are very tall or isolated structures; and
- Where there are structures of historic or cultural importance.
An assessment can be made taking account of the exposure risk and the following factors:
- Use to which the structure is put,
- Nature of its construction,
- Value of its contents or consequential effects,
- The location of the structure, and
- The height of the structure
The probability of a structure or building being struck by lightning in any one year is the product of the ‘lightning flash density’ and the ‘effective collection area’ of the structure. The lightning flash density, Ng is the number of [flash to ground ] per km2 per year, which can be calculated from the average number of thunder storm days in a given area.