There are simple measures that can be made by installers to meet the obligations of solar panel installations to ensure against wind-induced failure. There are also steps that can be taken to successfully navigate the more stringent requirements for commercial and larger scale projects to manage wind loading, including securing a project-specific structural sign-off. If larger scale installations are being undertaken on commercial property, often a project-specific sign-off by a qualified structural engineer prior to commencing the job is required. This is particularly relevant for tall buildings and large roofs.
Project-specific sign-off for commercial rooftop projects
It is important to know where the installer stands in a sometimes-complicated web of liability. It is normally the installer’s responsibility to ensure the panels are safely secured to the building, to protect them from wind-induced failure, including specification of roof fixings appropriate to the roof structure. Due to the value of a commercial system it is often worthwhile to sub-contract this responsibility to a qualified structural engineer. In this way, in the instance of a wind-induced failure, there is a clear path of liability back to the engineer who has signed off on the project.
A new version of AS/NZ1170.2: Wind Actions was released in 2011, which aims to ensure that the solar mounting supplier’s structural certificate is approved according to the latest version of the wind code.
The installer needs to seek and gain sign-off from the client’s structural engineer that the dead weight of the photovoltaic (PV) system will not impact on the safety of the roof or building’s structure. This is relevant when a ballasted solar mounting system is used, such as when the solar system is installed on a flat roof with a membrane, gravel or similar, the compression loads transferred to the roof cladding need to be approved, either by the client’s structural engineer or the manufacturer of the roof cladding.
On a commercial building, the original roofing contractor usually provides an extended warranty on the roof of up to 25 years. If there is no warranty on the roof, then the risk of leaks sits with the building occupier. Installers need to communicate clearly to clients about any penetration proposed and gain approval in writing, in case of any roof leaks in future.
Lachlan Bateman started his career developing a number of innovative and award-winning renewable energy projects in Australia, then moved to Europe to work for five years, fostering his passion for product and project development in the field of building integrated and mounted PV and off-grid energy systems. Since returning to Australia at the end of 2010, Lachlan established Clean Technology Partners in order to apply his experience in the fast-developing Australian solar industry. Since inception of the company, he has provided key input and advice on a number of larger scale projects including a 2 megawatt concentrated PV project in Mildura and a 267 kilowatt proof mounted PV project in Hervey Bay.
