The urban landscape is changing. As our cities strive to become greener and city dwellers push to see the return of biodiversity, living walls are now a common, exciting, and aesthetically pleasing sight. Also known as vertical gardens or green walls, these installations are constructed from modular panels, each housing vegetation growing on or against a vertical surface. Heralded as a way to not only welcome back nature, the walls are also associated with improved air quality and public wellbeing.
Companies are increasingly expected to play an active role in safeguarding the future of our planet and living walls have become a popular way to signpost an environmentally-conscious businesses. In the race to be green, however, the adoption of living walls has outpaced the implementation of proper regulations and permits, leaving the risks that these living walls pose to people and the buildings they’re attached to largely unexplored and unaddressed.
Professor Ed Galea, fire safety engineering group director at the University of Greenwich, has described the current regulations surrounding living walls as “inconsistent and inappropriate” and often contradictory. According to the Professor, there are currently no specific or relevant fire safety measures or maintenance requirements and the flammability tests and regulatory methods used today are designed for traditional building materials so are not fit for purpose and out of date.
Factors such as the plant’s age, health, chemical content and texture, coupled with daily and seasonal climatic variations all play into the flammability of a living wall installation. At the moment this is all left to chance.
Other important considerations include:
- Individual materials such as plants, growth media, plastics for modules, backing layers and wood – all of which are combustible
- The spatial arrangements of materials, including gaps and air pockets in the system itself and supporting structures
- Façade designs, where, for example, the living wall abuts windows or wall penetrations and fire can spread from within to the living wall, and from the living wall to the interior of the building
- The design of the system – such as the design of the irrigation network – can affect fire spread
- A lack of maintenance leading to dry matter increasing flammability and fire spread risk
- Environmental factors such as wind and climate change
- The structural load on the roof
- The installation of irrigation systems. If not connected adequately these systems can lead to water ingress/ leaking
- Quality of water - if wastewater is recycled inadequately, it could kill plants/attract pests
There have already been incidents of living wall related fires. In 2012, at a beer garden in Sydney, a customer used a candle to light a cigarette which caused a fern to catch fire. Within seconds the fire had engulfed the entire feature. In 2018, The Mandarin Oriental hotel in London saw its living wall installation, which spanned five facades, go up in flames. It had been installed with a felt pocket system that had no fire safety standards. A block of flats in west London in 2018 also sustained damage to its seventh and eighth floor corridors after its living wall and decking caught fire. All this points to a serious need to step back, take stock, and assess the danger of fire risks.
The insurance sector therefore has an important and integral role to play in the safe and sustainable development of green cities. By asking probing questions and raising concerns, brokers and underwriters can influence the design, installation and regulation of living walls to help ensure many more of these life-enhancing features can be built and that they grace our cities safely.