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When lightning strikes are you protected against this act of God? Print E-mail

The issue of lightning protection in churches is one that has exercised this publication for many years. In this four-part series of spotlights on the issue we will be revisiting various aspects of the subject, beginning with an overview of current thinking.

The nature of church architecture means they are particularly prone to lightning strikes. The very act of projecting the building towards heaven with a tower or spire – to glorify God and to act as a landmark for miles around – works towards them attracting lightning.

“Churches have always suffered from the effects of lightning.” That is the very start point of guidance published jointly by Historic England and Ecclesiastical Insurance. The document comprises a detailed summary of the history of church approaches to lightning strikes over the centuries, in particular the number of instances some buildings seem to have fallen victim. It quotes R H Golde, writing in his 1977 work Lightning Protection, as noting that the campanile of San Marco in Venice was hit and either severely damaged or destroyed no fewer than nine times between 1388 and 1762.

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New lightning conductor system that’s up to standard

Horizon recently removed an old and inadequate lightning conductor system from a church and replaced it with a new and up to standard system in line with BS EN 62305;2011

The old single bare copper down conductor had oxidised over the years and was not pleasing to look at, this was not helped by the unsightly installation of the tape by the original installer that had it running down the middle of the clock face of the church tower. Horizon removed the old tape by installation steeplejack ladders to the summit of the church spire and then using rope access techniques abseiled down the spire to remove the old tape and fixings.

Click here for the full story

In Britain the effects have not been so severe, as we suffer comparatively fewer strikes per hectare than elsewhere.

Early approaches by ecclesiastical authorities seem to have been that, as lightning is an act of God, there is no justification or need to attempt to protect a church against it. That attitude changed in the 19th century as technological advance resulted in the development of lightning protection systems based on the Franklin rod – a single metal rod leading to earth, in churches also known as a ‘tower-only’ system.

Until recently the great majority of churches still had that kind of basic protection, despite the introduction in the last century of a British Standard, BS6651, that recommended the more sophisticated Faraday Cage system, described by Ecclesiastical Insurance as ‘a mesh of conductors at intervals laid over the roof and down the walls of the building, and connected to earth by earth electrodes’.

When dealing with the issue of lightning protection in ancient or listed churches, as with any historic building, consideration has to be given to conservation issues.

In the joint Historic England/Ecclesiastical Insurance document Lightning Protection for Churches – a Guide to Design and Installation the policy of Historic England is stated thus:

“The installation of a lightning conductor implies in most cases the fixing of equipment to the fabric of a building. English Heritage seeks to ensure that any works to a historic building do not unnecessarily disturb or destroy historic fabric.“In deciding how best to protect a church from the effects of lightning the principals of minimum intervention and reversibility should be adopted wherever and whenever possible.”

In the same document Ecclesiastical points out that, although lightning protection is not a condition of cover “…installing lightning protection, as part of a risk assessment strategy, together with its on-going maintenance and testing, not only serves to protect the building for future generations to enjoy, but should help to reduce claims costs in the longer term.”

In 2008, a new European standard came into play: BS EN 62305. The new standard is considerably more complex than its predecessors and includes a requirement for a risk assessment to determine the level of protection required and sections devoted to both structural damage and risk to life, as well as damage to electrical installations and equipment.

Ecclesiastical Insurance has published a short guidance note to the main points of BS EN 62305. The company states: “This is only a brief summary of a very complex subject. Specialist advice must always be sought before installing any electrical equipment and installation must only be undertaken by competent persons.

“The design of a lightning protection system should be carried out by a specialist such as a consulting engineer, preferably a member of the Association of Consulting Engineers, with experience in lightning protection systems.”

Similarly, the company states that the installation should only be carried out by a competent and experienced contractor specialising in lightning protection systems.

A more extensive explanation of the differences between the old and new standards is the subject of a further joint publication, which allows updates of specific guidance documents. Again, it is a given that specialist advice should be sought.

The document states: “The most significant changes are the approach and enlargement of the risk assessment process and the inclusion, within the main body of the text, of specific guidance on the application and testing of surge protection devices as part of the risk assessment calculation.”

In future issues we will be considering the different kinds of damage that lightning can cause and the various ways of defending churches against it, and the issue of lightning protection in non-ecclesiastical historic buildings.

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