HEALTH, SAFETY & WELLBEING
Charles Darwin used during his voyage that later lead to his writing ‘On the Origin of Species’. Prior to his voyage, Darwin attended a lecture by Harris where the lightning protection system was demonstrated by way of a bath of water, small model ships, and a hand-cranked generator.
HMS Beagle’s voyage around South America, the Galapagos Islands, Australia, and South Africa took around five years. During that time the crew witnessed several occasions of lightning activity with at least two known and verified direct strikes to the ship itself. Captain Fitzroy noted that “nothing unusual had happened” and there was never the “slightest damage” as a result. Darwin himself commented, “But for the conductor, the results would have been serious.” On returning to Plymouth, Captain Fitzroy reported that the copper plates had all stayed in place, even on the smallest spars and had served to further strengthen, rather than weaken, them.
“No objection which appears to me valid, has yet been raised against them; and were I allowed to choose between having masts so fitted and the contrary, I should not have the slightest hesitation in deciding on those with Mr. Harris’ conductors.
“Whether they might be farther improved, as to position and other details, is for their ingenious inventor to consider and determine. He has already devoted so many years of valuable time and attention to the very important subject of defending ships against the stroke of electricity; and has succeeded so well for the benefit of others—at great inconvenience and expense to himself—that it is earnestly to be hoped that the Government, on behalf of this great maritime country, will, at the least, indemnify him for time employed and private funds expended in a public service of so useful and necessary a character.”
The Admiralty were convinced, and in 1842, Harris’ system became the first standard to be adopted for the protection of maritime vessels.
Harris continued to record known strikes and consequences of those strikes to ships and in 1853 a report was published claiming that, between 1830 and 1846 none of the ships that had been fitted with a Harris system had suffered casualties as a result of a lightning strike. In comparison, over a similar amount of time, at least 45 unprotected ships had suffered catastrophic damage and loss of life.
Harris’ system was saving lives, ships and cargo, but the first move towards modern lightning protection standards was not until 1905, when the report from the 1881 Lightning Rod Conference was made publicly available. The Society for the Protection of Ancient Buildings made a request to the British Standards Institution (BSI) for the writing and publication of a recognised code of practice for lightning protection and in 1942 the first Code of Practice Committee was convened with the Code of Practice number 1 (CP1) being published in 1943. Whilst largely based on the preceding 1881 conference report, several changes were made to take into account more recent developments in construction methods and standard conductor material sizes, which had become available.
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After a fire devastated a York Minster in 1984, which was believed to have resulted from a lightning strike, it was decided that a revision to the British Standard for lightning protection was needed, and in 1985 BS 6651 was first published (before being subject to several revisions and eventual withdrawal in 2008). Links to Harris’ systems were still obvious throughout the Standard, but revisions to risk assessment and surge protection recommendations were included to modernise the practice.
It is BS EN 62305 which is the bible of ATLAS lightning conductor engineers in Britain today. It was originally published in 2006, as four parts, but parts 1, 3 and 4 were revised in 2011 and part 2 (risk assessment) in 2012 (as this required further work). The current British Standard originated from the International Electrotechnical Commission’s (IEC) IEC 62305, which was passed to the European Committee for Electrotechnical Standardisation (CENELEC) where it would be re-published as the European standard for lightning protection, EN 62305. Individual member country committees then published their own versions, in BS EN 62305’s case this incorporated considerations for UK lightning activity and types of structures.
ATLAS was founded in 1946 to represent the leading lightning protection experts in the country, with all ATLAS members accredited to BS EN 62305, meaning there is no-one better qualified to protect your structure from lightning strikes. Ensure you are fully protected and contact an ATLAS member today.
www.atlas.org.uk/ TOMORROW’S FM | 43
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