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BS
6651 contains tables of materials suitable for use in Lightning
Protection System (LPS) components. Adherence to these requirements is
vital to avoid corrosion problems.
The correct choice of material and installation design should ensure a life span of 30 years for the earth electrode system.
The
code adequately details the requirement for inspecting an LPS, the
testing required and the detailed records that should be maintained.
Observance
of clauses 32 to 34 of the code will highlight any maintenance of the
system required. Of particular importance is the regular detailed
examination of the complete LPS for any evidence of corrosion. If this
check is not carried out then vital components within the LPS, which
may have suffered from corrosion and which could exhibit a high
resistance could be missed. This will have a detrimental effect on the
whole system making it an unattractive high impedance path for the
lightning current to follow.
To
minimise this problem, along with regular inspections, the selection of
the correct materials should be made in accordance with the
recommendations of BS 6651.
Before proceeding to design a lightning protection system, first carefully consider if the structure actually needs protection.
In
many cases, it is obvious that some form of protection is required.
High risk structures eg explosives factories, oil refineries, etc, will
require the highest possible class of lightning protection to be
provided. In many cases the need for protection is not so evident. BS
6651 provides a simple mathematical overall risk factor analysis for
assessing whether a structure needs protection.
Furse engineers have developed a program (strikerisk) to enable you to
calculate the lightning protection risk in accordance with the
requirements of BS 6651.
Strike
Risk is easy to use - you simply input the size and type of structure
to be protected together with relevant information about the location
and use of the building.
Strike
Risk will then calculate the risk of your chosen structure being struck
by lightning and advise whether protection is required (or not).
Strike Risk includes a Lightning Flash density map of the UK (derived from BS 6651:1999).
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