Stuart Bigwood, compliance and asset manager at chartered surveyors and auctioneers CPBigwood, examines the danger from lightning.

AN amateur photographer recently captured a stunning shot of a lightning bolt fizzing into the top of the famous Birmingham landmark the BT Tower.

It did not do any damage because the tower is fully protected but is your building up to scratch?

A lightning strike can cause structural damage, fire and loss of all electrical equipment and circuits.

Lightning discharges contain incredible amounts of electrical energy and have been measured from several thousand amps to over 200,000 amps. Even though a lightning discharge lasts just microseconds it can cause death and destruction.

Not being hit by lightning in the past has no bearing on being struck in the future. York Minster was around 600 years old when it was “eventually” hit by lightning in 1984, causing extensive irreplaceable damage.

For businesses, communications aerials and air conditioning units on the roof are an obvious target.

Most modern electronic systems are at risk, including the likes of computers, data communication networks, building management systems, telephone exchanges, CCTV equipment, fire and burglar alarms, power supplies, sensors and telemetry.

Loss of those systems would cripple industrial, commercial and governmental organisations alike.

Indeed, people in the trade will tell you that they continually come across people who have structural lightning protection for their building but have suffered damage to the electronic systems within.

That is because the secondary effects of lightning - short duration, high voltage spikes called transient overvoltages can, and do, cause equally catastrophic, if less visually obvious, damage to the electronic systems inside a building.

The history of lightning protection goes back to the lightning conductor, known as a lightening rod in the United States, which was invented by one of America’s Founding Fathers, Benjamin Franklin in 1749. The majority of lightning protection systems in use today remain of the traditional Franklin design.

The fundamental principle is to provide a sufficiently low impedance path for the lightning to travel through to reach ground without damaging the building. This is accomplished by surrounding it in what is known as a Faraday cage, advocated by the majority of national and international standards, whereby a system of lightning protection conductors and lightning rods are installed on the roof of a building to intercept any lightning before it strikes.

Today’s total solution approach means all systems should now be installed in line with BS EN 62305-2006, which includes interconnections with metallic bodies such as TV aerials plus surge protection to protect incoming power lines.

In addition Section 5 of Electricity at Work Act 1989 states that all lightning conductors should be visually inspected and tested at regular fixed intervals, preferably not exceeding 12 months.

Lightning can damage structures made of most materials, be they masonry, wood, concrete or steel.

The increasing pace of technological development means ever greater vulnerability if adequate lightning control systems are not in place.

The cost in terms of structural damage, damage to electrical systems and loss of business can be in the millions of pounds.