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roofing, cladding, insulation & structural systems
enhancing flat roof resilience to mitigate the risk of solar pv systems
A roof that houses photovoltaic (PV) panel systems should last at least as long as the expected life of the renewable energy system – typically around 25 years. However, affect its lifespan. So here, Ieuan Compton, International Strategic Marketing Manager on
The combination of the legislative drive towards greater energy efficiency, rising energy prices, and businesses’ sustainability goals all mean that PV systems are becoming an increasingly common requirement for the design of new commercial premises with flat roofs.
While they bring many benefits, PV panel roofs pose extra challenges compared to standard roofs. So, it’s important that architects and specifiers understand how to increase roof resilience. Greater loading and increased foot traffic When designing a commercial building with a flat roof that will house PV panels, increased loading and foot traffic should be factored into the design. The additional weight of the PV panels and their method of attachment will need to be included in the structural calculations. Mechanically fixing PV panels to the structural deck helps transfer the load and reduces stress on the roof surface. If this isn’t possible, PV systems can be ballasted or secured to rails, welded or bonded to the roof surface. However, the additional weight can compress the insulation layer, compromising thermal performance.
Once installed, solar panels need regular maintenance,
increasing foot traffic on the roof. This can damage the waterproof layer and can also potentially compress the insulation. PV panels equal a greater fire risk There are 29 fires for every GW of solar capacity installed on average1. Commercial deployment of solar panel systems in the UK has risen 42% year-on-year2, so it’s likely the number of fires experienced will increase too. If a fire does break out, the presence of PV panels changes its behaviour. The panels make fire harder to detect, and if the panels are below the optimum height, flames spread faster, too. The presence of the PV panels can hamper firefighting efforts because they can ‘stay live’ in daylight, making access dangerous. They also shield areas of the roof, making it difficult to extinguish the fire before it spreads, and they can add to the fire load, increasing potential losses. For this reason, insurer AXA states that PV panels must not be installed on combustible roofs.
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