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Insuring thatched roofs against lightning

Considering South Africa’s very high lightning flash density statistics, and the popular trend all over the country to use aesthetically pleasing thatched roofs for residential as well as commercial buildings, a fit-for-purpose offering has been introduced by DEHN Africa.

Based on DEHN’s modern high-voltage-resistant insulated (HVI) technology, this local insurance solution combines public and product liability, professional indemnity and the underwriting of electronic equipment insurance. As an added aesthetic bonus, the HVI technology makes use of lightning masts only 3 metres or less in length that are installed directly onto the roof, rather than the traditional 30-metre free-standing lightning masts that have been the norm for decades when protecting thatched roofs from the direct effects of lightning strikes.

The beauty – and pain – of thatched roofs

Hano Oelofse, managing director at DEHN Africa, says, “Thatched roofs are a visually pleasing option for game lodges and any other buildings looking to cultivate a rural or ‘countryside’ look and feel, but they require significant maintenance, including protective measures against the possibility of a fire outbreak. The direct lightning flash density measurements are high in large areas of South Africa, and direct lightning strikes can cause fires in these highly flammable roofs. Alternatively, lightning can cause a power surge, damaging electrical equipment and appliances in the same way as a power surge from an electrical utility source.

“At the same time, because they are so potentially flammable compared to other types of roof, the insurance requirements on buildings with thatched roofs can be onerous – a thatched roof is regarded as a non-standard construction by many insurers, in contrast to roofs made of tile, slate, concrete, asbestos, metal or zinc. Therefore, amongst other criteria, an insurance company requires the owner of a thatched roof building to take steps to reduce fire risk.”

According to the terms and conditions of insurance underwriters as regards thatched roofs:

• All insurance companies require that a lightning protection system (LPS) be installed, as per SANS Code of Practice 10313.

• A certificate of compliance (COC) is required before the insurance policy can be underwritten, as a method of assurance that the components will work and the workmanship is compliant.

• Whenever a property is sold, the COC must be renewed.

Protecting thatched roofs from lightning strikes

Traditionally, external lightning protective equipment for thatched roofs has involved the use of a free-standing lightning mast, which must be higher than the thatched roof, Oelofse explains. “The idea is that the lightning flash will ‘seek’ a pathway to the ground and thereby discharge itself through the lightning mast; preventing your flammable roof from being struck by the lightning instead.

“However, the masts are very visible, which from an environmental perspective somewhat defeats the objective of having the thatched roof blend into the environment. The mast has to be installed at a height derived from the lightning risk assessment whereby the correct angle of protection is given according to each lightning protection level. The lightning mast must be high enough to cover the entire building.

“A free-standing lightning mast must be earthed and bonded sufficiently, and also needs to be serviced annually, otherwise insufficient bonding and earthing of the free-standing mast may lead to flashovers to the thatch roof and hazardous step and touch potentials around the mast. A mast alone is not sufficient to prevent damage to the equipment in your home, and so you still need a separate surge protective device.”

Lighting protection for new design possibilities

In contrast to the 30-metre free-standing mast, DEHN’s HVI lightning protection system is compact and neat, and is installed onto the top of the roof itself. Thinner and shorter than the old technology, with average lengths of between two and a half and three metres, the HVI is far less visible to the naked eye than a 30-metre free-standing mast, and therefore more visually pleasing.

Oelofse notes that for the client – namely both the homeowner and architect – this means optimal adjustment to the architecture of the building and opens up new design possibilities. “At the same time, however, the HVI system provides arguably even better protection from a lightning strike than a 30-metre mast, and it has also been proven to be very cost-effective both from an installation and maintenance point of view.”

New insurance solution

Given the technical expertise offered by the HVI technology, and the company’s confidence in its product, DEHN Africa is now prepared to offer insurance guarantees linked to its HVI system through the launch of DEHNsure for thatched roofs, powered by HVI and providing a three-in-one offering.

“We believe this is a first in South Africa, where vast areas of our country are prone to the high possibility of a lightning strike at different times of the year,” says Oelofse. “DEHN Africa is therefore proud to introduce DEHNsure for thatched roofs. This three-in-one offering means that insurance companies will have the surety and peace of mind of knowing that the damages that they used to pay for, or equipment that they used to replace due to lightning strikes, will now be covered or repaid by DEHN Africa, according to the applicable terms and conditions. This is all due to the combination of today’s technology improvements in lightning protection and DEHN Africa’s faith in our products, systems, employees and solutions.”

Technical considerations

DEHN’s LPS components for use specifically on thatched roofs are recommended for the following reasons:

• The lightning current-carrying core of these conductors is coated with insulating material in such a way that the required separation distance to other conductive structural features or electrical lines and pipes is easily maintained. There are no further measures required.

• Flexibility and safety at the highest level are offered.

• Appearance and design are becoming increasingly important for modern buildings.

• HVI conductors can be installed behind the façade, while HVI conductors with grey sheathing can be painted the same colour as the building.

• For the client (homeowner and architect) this means optimal adjustment to the architecture of the building and new design possibilities.

• Installation takes place directly next to conductive structural parts or electrical lines or pipes.

• Additionally, these LPS components for use specifically on thatched roofs are easy to mount through the use of modular components and special tools, such as the HVI-Strip.

• The LPS components are also flexible when retrofitting, and subsequent installation on the roof is possible without adapting the lightning protection system.

“The simplicity and improved aesthetics of HVI lightning protection for thatched roofs, as well as the impressive cost and maintenance requirements of the new technology when compared to the old free-standing masts, show that this is indeed the way of the future. Whether your thatched roof is in a residential area, a commercial site or a game lodge, the combination of DEHN’s HVI technology and this new insurance offering from DEHN Africa will have something to interest all thatched roof lovers and owners,” concludes Oelofse.

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