We need to plug gaps in knowledge on fire safety to enable resilient mass timber construction

Despite the hype, the timber building revolution is yet to materialise. Mass timber structures offer significant potential to help decarbonise a sector responsible for 37% of global emissions. However, gaps in local country codes and regulations around the world are not giving property developers the confidence they need to back timber.

While countries like the US, Canada, Australia and several European nations have robust regulatory frameworks that specifically address mass timber construction, many other regions are just beginning their journey.

Promising low-carbon alternative materials that can be used at scale are hard to come by, but mass timber holds promise. The UNEP estimates substituting conventional materials with mass timber could reduce global emissions by 14-31%. However, uncertainty around fire-safe design is deterring developers and their advisors from fully realising the potential of mass timber buildings. That’s why we have shared our risk-based Fire Safe Design Guide for Mass Timber Buildings to help everyone from fire safety engineers and architects to insurance companies and property developers answer essential questions around fire-safe mass timber building design.

When mass-timber makes the most sense

The guide focuses on building typologies where mass timber has the greatest potential – office and residential buildings up to 50m tall and educational buildings up to 25m tall. Often the sustainability benefits of mass timber structures diminish as the building height increases.

Gaps in knowledge and regulations on fire safety for mass-timber buildings creates uncertainties for property developers over which fire safety measures are required to address the specific hazards posed by mass timber and ultimately what all this means for design and whole life carbon.

The risk-base guide helps property developers exploring the use of mass timber to answer essential questions early on. For example, which fire safety measures are required to address the specific fire hazards posed by mass timber? Can all mass timber remain exposed or where does it require encapsulation? What fire performance and specification is appropriate for the mass timber components? Is a single-stair building compatible with safe mass timber construction? Should mass timber be employed in the construction of external walls?

The guide focuses on setting out these key fire safety precautions that should be provided in a building to address the fire hazards posed by the mass timber construction, depending on the risk profile of the building. This is essential to enable informed decision making at the early concept stage of projects. Questions like these will have a big impact on the design and cost of a project.

It draws on decades of Arup involvement in research and design on fire safety engineering for mass timber structures, for example the development of many landmark projects such as the Sky Believe in Better Building in the UK and the Galkangu Bendigo GovHub building in Australia.

Most recently Arup has conducted some of the largest timber fire safety experiments in the world, in collaboration with Imperial College London and CERIB in France. The Code Red research project saw a series of full-scale fire experiments in a 350 sq m compartment with mass timber ceilings, to help the industry better understand how fires would grow, develop, and decay in an open-plan space such as offices. Arup is also contributing to the development of codes and standards around the world.

The better the understanding of fire-safety, the more confidence property developers can have in appropriately planning and costing out projects. If we are to really move the dial on decarbonising the sector then we need to use the least amount of the right material, in the right place. Mass timber buildings are generally lower carbon if used efficiently, but it is important to look at the entire building (not just bare structure), and its location, and assess this on a case-by-case basis, over the whole-life cycle.

Knowledge sharing to enable informed decision making is crucial to this and that’s why we’re sharing this guide.

Judith Schulz is fire safety engineering lead at Arup