Background
Since the turn of the century the use of Cross Laminated Timber (CLT) in construction has increased significantly and is considered the future successor of the traditionally vast use of concrete elements in mid- and high-rise buildings. Sustainability is the main driver as wood is a lasting and easy recyclable resource. The use of wood for buildings fits into the biogenic circle in life cycle assessments (LCA) as opposed to concrete with its scarcity of necessary components and highly energy dependent processes. Moreover, CLT improves indoor climate, aesthetics and architecture and has economic advantages with a faster path for inhabitants to move in, due to the dry building process.
By using wood as the main- and loadbearing structures in mid- and high-rise buildings, a significant combustible source is introduced. This increased level of combustibles will change the fire dynamics of the building and may have consequences which can increase the risk of structural collapse.
Project Description
Architects applaud the aesthetics of wood and make designs where the wood is exposed, for example in considerable open spaces within multi-storey office and residential buildings. This does not fit into the prescriptive legal framework and puts these buildings in a category where Fire Safety Engineering, simulation, CFD analysis etc. are deployed to reach a satisfied safety level in accordance with the current National Building Code(s). Predominant strategies mainly resort to Active Fire Protection Systems such as early detection and warning, and automatic sprinkler / water mist systems. Fire Safety Engineering (1) and Active Fire Protection Systems (2) are respectively associated with; 1: expectations that selected / estimated scenario(s) reflect the actual risk and consequence scenario (including the unthinkable), moreover, human behaviour, and 2: a risk of malfunction.
Recent studies (Ian Pope et al) point at changed fire dynamics and behaviour when CLT is involved in a fire, i.e., a more rapid growth phase and extended burning during the decay phase as the CLT suffers from delamination (structural instability) and char layers falling off. Thus, a recurring fire circle is started.
Being a considerable calorific contribution to the total fire load of the building and inventory, this and other studies points to, not only a more aggressive fire growth, but also to an additional external heat release in CLT enclosed compartments.
The purpose of the project is to assess whether CLT in mid- and high-rise buildings, can be designed in compliance to National Building Codes, with a Passive Fire Protection approach, and in accordance with the architectural / design frame as given above.
ROCKWOOL is highly focussed on megatrends in the built environment and wants to contribute with novel, well-thought-out and proven solutions, and services to the market. To create and provide such, we want to stay in the frontline of knowledge to develop science-based applications that meets both market and legal demands in a global perspective. Not least contributes to human safety, health and the environment.
Suggestions for sub-tasks could be:
- Literature study of fire behaviour in CLT buildings
- Scrutinizing Nordic Building Codes and regulators approach to the legal framework around CLT
- Interviews with Architects, Specifiers, Building and Fire authorities
- Ideation on Passive Fire Protection Systems / measures
- Small and mid-scale fire testing
- Dissemination
ROCKWOOL Supervisors / competencies
- Søren Rud Pedersen (Senior R&D Specialist, Resistance to Fire testing, Product Development, First Responder knowledge, srp@rockwool.com)
- Kurt Munk (Chief Specialist Fire Protection, Resistance to Fire testing etc, kurt.munk@rockwool.com)
- Kurt Ejlersen, (Chief Technician, Reaction to Fire testing, kurt.ejlersen@rockwool.com)
- Karen Guldhammer Skov, (R&D Engineer, Modelling and Simulation Analysis, karen.guldhammer@rockwool.com)
Facilities
- Access to ROCKWOOL R&D Fire Labs (Resistance and Reaction to fire, small to medium scale)
- Access to ROCKWOOL R&D Stone Wool characterisation and test labs (inorganic and organic chemistry, mechanical and physical testing)
- Possibilities for external testing can be included if relevant
Confidentiality
Students are required to sign a non-disclosure agreement (NDA) with Rockwool. Exam and report will be kept confidential.
References
- FIRE SAFETY STRATEGIES FOR TALLER TIMBER BUILDINGS, Ian Pope, Leo Menzemer, Ahmed Ali, Ana Sauca and Anders Dragsted, DBI –The Danish Institute of Fire and Security Technology
- FIRES IN MODERN TIMBER BUILDINGS, Dr Daniel Brandon, RISE Research Institutes of Sweden
- Full-scale fire experiments of rooms with cross-laminated timber elements, PhD Andreas Sæter Bøe, RISE Fire Research (FRIC project), Trondheim, Norway