Lightning protection for historical properties is essential. This is very important for the purpose of protecting and preserving the heritage of a period property. Nevertheless, historical buildings aren't locations which were created with lightning protection as a key priority, so it’s crucial that the appearance of the system doesn’t appear out of character or intrusive. The materials used have to do a reliable job, while not affecting the historical appearance of the building. Installing a lightning conductor to any historic building requires a qualified contractor, who understands the importance of the nature of the construction and installs the system sympathetically.
With this in mind in this blog, we discuss with you, the implications of lighting protection for historic buildings relating to what you need to know. Read on to find out more!
Where to begin?
Historic England recommends that lightning protection should be used for all churches, tall or prominent historical structures. However there is not a specific system in place that gives full protection, and the significance of a building requires to be balanced against an acceptable amount of protection. Historic England’s recommended guidelines are:
This guidance offers advice on the design, installation and maintenance of lightning protection systems for architects, surveyors, engineers and others involved in the care and safeguarding of historic buildings or period properties. Lightning protection is specialist work and requires quality design and installation.
An 8mm circular copper conductor is often used on historic buildings. This can be sheathed with coloured PVC so that it doesn’t look out of place in the surroundings of the building. The aim is to make the conductor appear to be part of the building, instead of contrasting with it. It is also essential that the conductors are put in place to decrease visual impact. It is a possibility for a lightning protection system to be put in place sympathetically, while still adhering to the relevant safety standards. A thorough system can be made by placing the conductors out of sight behind buttresses, leaving the buildings aesthetic appearance undamaged.
The air termination is able to be hidden out of place behind parapet walls and the down conductors can be placed behind pinnacles, they should be put in place to follow the lines of the building. They don’t need to be dressed into each contour or crack of the stone on rubble or pitch-faced stonework, as this can make a poor aesthetic finish.
The building’s main features can cover the visual effects of the conductor. Moreover, it is effective to shadow a strong feature on a tower or spire by following a stone quoin, as the eye tends to hone in on the more prominent features – not realising a conductor placed next to it.
Putting a lightning conductor in place on any historic building will need a qualified contractor, who understands the importance of the nature of the construction and installs the system properly.
The spires and towers of historic churches and other tall buildings are frequently targets for lightning strikes. Although lightning protection isn’t not a legal requirement, insurance companies will likely require churches and prominent historic buildings to have lightning and surge protection. This following information provides advice on the design of new or improved lightning protection and surge protection systems:
Lightning damage and thunderstorms and lightning frequently occur when the weather is warmer and more humid. In England thunderstorms are likely to occur in the East Midlands and South East areas. Climate change research indicates that the number and power of lightning storms are more likely to increase over this century in the British Isles. What’s more, lightning strikes are more likely to become common in the future, lightning is a very high current discharge. It can happen between or within highly charged clouds or from a cloud to earth. These discharges can range from about 10 million to 100 million volts.
Lightning strikes to earth usually seek out the path with the most little resistance. This will be the highest point in a landscape, such as the top of a mountain, a tree, or a spire or tower. Since lots of historic churches and similar buildings have spires and towers, they can often be prone to lightning strikes although this is unpredictable where lightning will actually hit. If the discharge is uncontrolled or not discharged safely, there is a risk to the structure and its contents.
Most direct damage caused by lightning is usually small. The weakening of copings, pinnacles and roof tiles, for instance. However, even smaller damage can be costly to repair if high-level access is required. Moreover, masonry damaged by lightning can sometimes fall, posing a significant danger to people. There is some evidence that lightning damage is more extensive on towers or spires where the masonry or jointing is in poor condition. The damage might be caused by the sonic boom effect created by the rapid vaporisation of the moisture in the air. This stresses the need for regular building maintenance and repair. The possibility of fire from a direct lightning strike is low. Most recorded cases of church fires begun by lightning are from the Victoria era. These fires are usually caused when the strike melted lead pipes and ignited the escaping gas. With the advent of electric lighting, this risk was significantly decreased.
Lightning strikes make voltage surges, which in turn can cause an electrical system to break down, malfunction, or even a complete burn out of wiring and equipment. The more vulnerable items are alarms, boiler controls, sound reproduction systems, computers, telephones and electronic organs and so on. Around 60% of insurance claims for lightning damage to historical buildings are for damage to electrical wiring and equipment. The damage may be more common than structural damage, it is essential to realise that it is far less costly. Repairing structural damage is on average three times more expensive.
Risk assessment for lighting protection
Risk assessment is something that is essential for safe lighting installation. Prior to installation or getting a lighting system installed, a fully qualified installer will need to carry out a full risk assessment. This will involve a lengthy process which involved working out a few calculations with computer software being necessary. Owners of the property of custodians are the individuals who are required to to help collate as much of the information as possible. This will in turn make the process much easier and also help assessors in determining the necessary level of protection required.
The engineer will need a couple of pieces of information which will include:
Here at Rodells we’ve been installing and maintaining Lightning Protection Systems within Commercial, Historic and Ecclesiatical buildings going back since the 19th Century. You might not realise it but a great deal of businesses require their buildings to be protected against lightning. You may not necessarily be required to install a lightning protection system, but it is certainly worth getting in touch with our professionals for a thorough risk assessment, this is due to the fact that strikes can cause damage to equipment, power surges and system failures, which can lead to injuries and business downtime. To find out more, please get in touch with us or visit our website.