New Guide: Arup Tackles Fire Safety for Mass Timber’s Sweet Spot

The 191-page guideline tackles low and mid-rise construction worldwide

Mon 03 Jun 24


Interest in mass timber is on the rise worldwide, with architects and developers turning to timber-based systems to tackle building emissions. However, despite a surge of new buildings in the North American markets, local building codes and standards vary substantially from country to country, creating roadblocks to greater adoption.

That is according to a new guideline produced by Arup, Fire Safe Design of Mass Timber Buildings. The guideline provides an evidence-based approach to plugging gaps in local country-building regulations. It also examines scenarios where cross-laminated timber, glulam, and laminated veneer lumber can replace traditional steel-and-concrete systems.

“While the US, Canada, Australia, and some European countries have mature regulatory frameworks, many other countries don’t,” the authors of the 191-page guideline said, with the Guide looking at timber in external walls and specific fire hazards for different building components.

Screenshot 1 6 2024 111024
In 2021, Arup worked with CERIB (in France) and the fire science group at Imperial College London (Hazelab) on a series of full-scale fire experiments in a large, purpose-built 352m2 compartmental building. The experiments investigated the impact of large areas of exposed mass timber on the fire dynamics that occur in an open-plan compartment and to understand how exposed timber structures withstand fire decay and smouldering. (Photo Credit: Arup)

“The new Guide has been written to be used in any statutory jurisdiction,” according to Arup, who added, “where local codes and regulations exceed the recommendations in this Guide, they will take precedence.”

As a result, “the purpose of the Guide is to provide (fire engineers and) designers with risk-based tools to assist in the design of adequate fire safety in buildings that use a mass timber structure.”

Up to 50m tall

The Guide addresses building typologies where mass timber has the most significant potential—mid-rise office and residential buildings (up to 50 metres) and educational low-rise buildings (up to 25 metres).

According to Judith Schulz, Arup’s fire safety engineering lead: “As well as gaps in codes and regulations, there is also a lack of knowledge amongst much of the design and construction community when it comes to designing fire-safe timber buildings.”  

The new guideline draws on Arup’s decades-long experience designing mass timber structures, such as UK broadcaster Sky’s “Believe in Better” building in London. Footage courtesy of @arupgroup.

“We hope this Guide will accelerate a move away from carbon-intensive materials and contribute to a growth in fire-safe mass timber buildings, which offer great promise for reducing CO2 in low- to medium-rise buildings,” Ms Schultz said, was part of an Arup team assisted by Dr Michael Klippel (IGNIS) and Dr Andy Buchanan (PTL Structural & Fire Consultants) in putting the guideline together.

What is the sweet spot for mass timber systems?

Last month, Wood Central reported that switching steel for CLT floors, glulam beams, and columns holds the key to lighter, faster and greener construction according to a study, Comparison of Embodied Carbon of a Mass Timber Building Structure with a Steel Equivalent, published in Buildings Journal.

US developers are now using new forms of mass timber, like mass ply panelling to build faster, greener and lighter mid-rise and high-rise buildings across the US. Including the world's first post and plate high-rise in Oakland, California. (Photo Credit: DCI Engineers)
US developers are now using new forms of mass timber, like mass ply panelling, to build faster, greener and lighter mid-rise and high-rise buildings across the US. Including the world’s first post and plate high-rise in Oakland, California. (Photo Credit: DCI Engineers)

At the same time, a report from PCL Construction, one of North America’s largest construction contractors, DCI Engineers, the engineers behind the world’s first post-and-plate mass timber high-rise, and design firm Weber Thompson found that mass timber hybrid high-rises are (almost) as cost-competitive as concrete-based systems and are the ideal material to build 12-18-storey mixed-use and residential towers.

That study confirms that ‘intermediate high-rise’ is the sweet spot for timber-based construction systems, adding that buildings “are often underbuilt in urban areas due to an unfortunate intersection of construction code and code requirements.”


  • Jason Ross

    Jason Ross, publisher, is a 15-year professional in building and construction, connecting with more than 400 specifiers. A Gottstein Fellowship recipient, he is passionate about growing the market for wood-based information. Jason is Wood Central's in-house emcee and is available for corporate host and MC services.


Related Articles