British Standard EN 62305 Summary
The new British Standard, numbered BS EN 62305 encompasses:
62305-1 General Principles:
Essentially describes how to design a Lightning Protection System (LPS) in accordance with the accompanying suite of standards.
62305-2 Risk Management:
One of the most important changes is that the approach put forward by the new standard to risk management means looking at risk in a far broader
sense than merely the physical damage that can be caused to a structure by a lightning discharge i.e. the risk of loss of human life, loss of service
to the public, loss of cultural heritage and economic loss. It therefore embraces many more complex 'weighting factors' than its equivalent section in
BS 6651. It takes into account the services (telecom and power) that feed the structure, along with aspects such as any provisions that may have
been taken during the construction of the structure to reduce the consequence of fire.
62305-3 Physical Damage to Structures and life Hazard:
This part has 4 classes or protection levels of Lightning Protection System (LPS) as opposed to the basic two (ordinary and high risk) levels in BS
6651. It provides the designer with three fundamental methods to protect a structure, namely a) the rolling sphere, b) mesh or c) protective angle
method, and assigns different sizes, spacings and angles to suit each class of LPS. It contains five annexes, annex E being particularly useful for
anyone designing, constructing or carrying out maintenance and inspection of an LPS.
62305-4 Electrical and Electronic Systems within Structures:
Covers the protection of electrical and electronic systems housed within structures. This part of the new standard essentially embodies what annex C
in BS 6651 carried out, but with a new zonal approach referred to as lightning protection zones (LPZ). It provides information for the design,
installation, inspection , maintenance and testing of an LEMP protection system for electrical/electronic systems within a structure.
