Industry brings clarity on fire compliance for mass timber buildings

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Collaborative research helps illuminate fire safety design guidelines

OFR Consultants, a leading fire engineering consultancy, has partnered with the Structural Timber Association (STA) to provide the wider industry with much-needed clarity on the fire safety design of mass timber buildings.

Their joint research into cross laminated timber (CLT) compartment fire behaviour has been published in Volume 6 of the STA’s Fire Safety in Use Guidance.

This study was an ambitious attempt to ascertain the relationship between different building heights, uses and consequence classes.

Not forgetting the critical performance expectations of structures in a fire situation.

Solving challenges in fire compliance for mass timber buildings

The primary hurdles in delivering mass timber buildings stem from confusion around compliance with Building Regulations.

This includes understanding what evidence designers need to furnish to show their compliance.

The newly revised guidance is a crucial resource for designers and building control bodies.

It offers a consistent approach to the design of mass timber buildings.

It also sets the expectation of what types of solutions and analysis should be expected based on a building’s height and use.

Dr Danny Hopkin, OFR Technical Director and co-lead author on the project, shed light on their initiative: “OFR is the lead research partner delivering the STA special interest group (SIG) project on cross laminated timber (CLT) compartment fire behaviour.”

“The study identified that higher consequence buildings should survive the full duration of a fire, while lower consequence buildings should survive long enough to enable occupants to escape and facilitate fire service activities.”

He emphasised the importance of this distinction in helping engineers create the correct evidence to support their designs while demonstrating compliance with the Building Regulations.

Hopkin expressed his satisfaction with the outcome of the study: “We’re delighted that this study has been developed into industry guidance via Volume 6 of the Fire Safety in Use Guidance.”

He continued: “Together with my co-lead author and OFR colleague Research Leader, Mike Spearpoint, we suggest that the guidance should be viewed on a project-by-project basis.”

This involves considering the specific fire safety strategy for each building and the input from all key stakeholders.

The new fire compliance guidance encourages dialogue

Andrew Orris at STA echoed these sentiments: “This new guidance encourages dialogue with approving authorities to establish the structural fire performance objectives.”

This involves considering factors such as the evacuation mode, fire service provisions, and the addition of fire safety systems like sprinklers.

It also features an appendix of application examples to help designers apply the guidance effectively.

Upon completion, the guidance underwent independent review by a stakeholder review panel.

Following two and a half years of use by designers, the STA has updated the document to incorporate user feedback.

OFR has remained a steady guiding hand, overseeing these changes to ensure alignment with the original intent.

This was achieved by reviewing and editing the second edition.

You can access the standard Volume 6 of the fire safety in use guidance here.

IFSJ Comment

We recognise the significant impact of this collaboration on the wider industry. By clarifying key points on fire compliance in mass timber building design, OFR and the STA are providing a crucial step forward in making such structures safer and more reliable.

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