Living wall fire regulations UK: what architects and specifiers need to know

Living walls are increasingly being specified on commercial buildings, residential developments and public spaces across the UK. Alongside their contribution to biodiversity, air quality, rainwater management and greener urban environments, there is another important consideration for architects and specifiers: living wall fire safety. What are the UK fire regulations for living walls? How is the fire performance of a green wall assessed? And what should architects, landscape architects and contractors consider when specifying a living wall system? Here we look at some of the key considerations surrounding living wall fire regulations in the UK.

Are there specific fire regulations for living walls?

There is currently no single UK fire regulation written specifically for living walls. Instead, living walls need to be considered within the wider fire safety requirements applicable to the building and, where relevant, the external wall. In England, fire safety requirements for buildings are addressed through the Building Regulations and supporting guidance including Approved Document B. The requirements affecting an individual project will depend on factors including the height, use and construction of the building, together with the position and design of the living wall. This means there is no single living wall specification that will be appropriate for every project. Early consultation between the architect, fire engineer, façade consultant, landscape architect, living wall specialist and Building Control can therefore be particularly important.

What does a living wall fire rating mean?

Building products and systems can be classified according to their reaction to fire performance under BS EN 13501-1. You may see classifications expressed using letters and numbers such as:

B-s2,d0

The different elements of the classification relate to reaction to fire, smoke production and the production of flaming droplets or particles. Reaction to fire classifications run from A1 through to F, with A1 representing materials making no contribution to fire. Smoke production is classified from s1 to s3, while flaming droplets and particles are classified from d0 to d2. It is important to understand the precise classification and supporting test documentation relating to the living wall system being considered.

Is there a fire rated Mobilane living wall?

Mobilane’s MobiPanel living wall system complies with fire classification B-s2,d0. MobiPanel is a modular outdoor living wall system designed for both existing buildings and new developments. Its interchangeable plant cassettes can be used on flat and curved walls and an automated irrigation and drainage system provides an even supply of water. For architects and specifiers considering a living wall where fire performance forms part of the project requirements, system specific technical information can be provided as part of the specification process.

Why should the whole living wall system be considered?

A living wall is more than a collection of plants attached to a building. It is a system incorporating planting, growing media, irrigation, support structures, fixings and interfaces with the building. These elements, and the way they are configured, can influence fire performance. The substrate behind a material, its orientation, cavities, fixings and combination with other materials can all affect how a construction performs. For this reason, fire performance should be considered in relation to the complete proposed installation rather than assuming that the performance of one individual component represents the performance of the entire wall.

Does irrigation affect living wall fire safety?

Water management is fundamental to the successful operation of a living wall. A healthy living wall is designed to maintain suitable moisture levels for its plants and growing environment. A wall that is allowed to become excessively dry presents very different conditions. MobiPanel uses an automated irrigation and drainage system designed to provide an even supply of water to the plants. Effective irrigation should therefore be considered as part of both the horticultural and operational management of a living wall. Regular checks of the irrigation system can help identify faults and prevent prolonged periods of drying.

Does plant selection matter?

Plant selection is another consideration when designing and maintaining living walls. Different plants have different characteristics. Some species contain greater levels of oils or resins, while others naturally retain higher moisture levels. The amount of dead foliage produced throughout the seasons can also vary considerably. Planting design should therefore consider the long term performance of the wall as well as biodiversity, aesthetics, orientation, microclimate and seasonal interest. Appropriate plant selection combined with professional maintenance helps keep the wall healthy and prevents excessive quantities of dead or dry vegetation from accumulating.

The importance of living wall maintenance

Fire safety considerations do not end when a living wall has been installed. Living walls are dynamic landscapes and their condition changes over time. Regular professional maintenance should include:

• • Monitoring plant health
  • Checking irrigation performance
  • Removing dead and dry vegetation
  • Checking moisture levels
  • Replacing unsuccessful plants where necessary
  • Inspecting the overall condition of the system.

This helps ensure the wall continues to operate in the way it was designed.

Can fire breaks be incorporated into living walls?

Depending on the scale, location and fire strategy of a project, it may be appropriate to incorporate fire breaks or interruptions within areas of vegetation. These can help prevent uninterrupted vegetation extending across large areas of a façade. The requirement, location and specification of any fire breaks should be determined by appropriately qualified professionals as part of the building’s overall fire strategy.

Living wall specification should start early

The most effective approach is to consider living wall fire safety during the design and specification process rather than treating it as an issue to resolve immediately before installation. Early collaboration makes it possible to consider:

• • The proposed living wall system
  • Building height and use
  • Façade construction
  • Supporting materials and fixings
  • Fire performance requirements
  • Irrigation
  • Plant selection
  • Maintenance access
  • Fire breaks where required
  • Long term management.

This allows the living wall to be considered as part of the wider building design.

Specifying a Mobilane living wall

Mobilane works with architects, landscape architects, contractors and developers to integrate living walls and green façades into both new and existing developments. The MobiPanel living wall system complies with fire classification B-s2,d0 and combines a modular, lightweight construction with interchangeable plant cassettes and automated irrigation and drainage. Mobilane can provide technical information and specification support to project teams considering living walls for their developments. Fire safety requirements are project specific and regulations and guidance continue to develop. The requirements for an individual building should always be established with the project’s architect, fire engineer, Building Control and other appropriately qualified professionals.

Planning a living wall project?

Contact Mobilane to discuss your project, request technical information or explore the most appropriate living wall solution for your specification.