The demand to use mass timber in construction is increasing as society seeks to build with more sustainable materials. Building codes and design guidance for using mass timber vary substantially country to country as does the foundation on which the local codes have been developed. Source: Timberbiz
Canada, Australia, the US and some European countries have regulatory frameworks, many other countries don’t.
Mass timber is a combustible construction material and may present a hazard for buildings. In a fire, exposed timber can contribute additional fuel to the fire, increasing the intensity and/or duration of the fire relative to a building of non-combustible construction and increasing the collapse risk.
To support the fire safe design of mass timber buildings, Arup has developed a guide which proposes features to be incorporated into the design for residential, education and business occupancies (up to 50m tall for residential and business use and up to 25m tall for education use) which have a mass timber structure.
From Arup’s experience, these types of buildings currently have the greatest demand for using mass timber in their construction.
This document is primarily aimed at fire safety engineers, but also provides practical guidance for others involved in the design and construction of mass timber buildings, such as architects, clients, and contractors.
To develop this guidance, Arup reviewed and analysed an extensive range of public documentation recording the fire dynamics in compartments of varying sizes and with differing degrees of exposed mass timber.
Arup has previously co-funded compartment fire experiments and has undertaken a series of large-scale compartment experiments that have informed this document. Arup has also gained valuable experience through the development and statutory approval of mass timber building solutions worldwide.
The Guide considers the different hazards that building users (for residential, education, and business occupancies) may experience, such as their familiarity with a building, and whether they are awake and alert or asleep. Additionally, the building height must be considered, as this can impact on firefighting operations and the time taken for occupants to evacuate.
Using the existing compartment fire dynamics data available to Arup, combined with Arup’s experience in understanding the fire hazards for a building based upon the occupancy type and height, allows for a qualitative assessment of the resulting risk.
Design features such as evacuation strategy, fire protection measures or encapsulation of timber, can be introduced to reduce the fire risk to occupants and firefighters.
The recommendations within the Guide are applicable to CLT Panel Construction, Mass Timber Frame Construction and Timber Hybrid Structures. Other mass timber floor systems such as nail laminated timber and dowel laminated timber floor systems are not directly addressed, though this Guide may be suitable for use with these composite timber systems, and this would be at the discretion of the fire safety engineer using the Guide.
The Guide is not applicable to lightweight timber frame construction.
You can download the guide here.
