Many congratulations to Alastair Bartlett, a 2014 MEng Graduate in Structural and Fire Safety Engineering from the BRE Centre for Fire Safety Engineering, who has been awarded the 2014 Student Scholar Award from the Educational and Scientific Foundation of the SFPE. The award was made for Alastair's MEng Thesis, entitled "Charring Rates for Cross Laminated Timber under Standard and Non-Standard Heating Scenarios," which was supervised by Luke Bisby and Rory Hadden.
Alastair will present his work at the SFPE Annual Conference in California this autumn, and has recently signed up to undertake an Arup/EPSRC CASE PhD Studentship at the University of Edinburgh, supervised by Rory Hadden (and Luke Bisby), continuing his work to study the fire performance of mass timber buildings.
Alastair and his MEng thesis partner, Andrew Ballantyne, along with Rory and Luke, are currently working on a journal paper to present their findings, and we expect that this will be published and posted on this Blog in due course.
The formal SFPE Award Citation is included below:
Educational & Scientific Foundation Chair’s Message
"The Educational and Scientific Foundation is happy to announce that the winning paper for the 2014 Student Scholar Award entitled "Charring Rates for Cross Laminated Timber under Standard and Non-Standard Heating Scenarios" was submitted by Alastair Bartlett. Alastair undertook his thesis work as part of a five year Master’s degree program in Structural and Fire Safety Engineering at the University of Edinburgh in Scotland, UK. His advisors were Professor Luke Bisby and Dr Rory Hadden.
Alastair will be presenting his paper at our SFPE Annual Conference in Long Beach, CA in October of this year. Please make sure to attend the meeting and join us for Alastair Bartlett's presentation."
A Brief Summary of the Work is as Follows
The use of engineered timber products such as cross-laminated timber (CLT) in high-rise construction is of increasing interest to architects, designers and the general public. A key factor preventing widespread uptake of this construction methods is a lack of understanding relating to the performance of engineered timber in fire. This presents a barrier to the construction of high-rise, sustainable timber structures. This thesis provides a more in-depth, practical knowledge of the behaviour of timber across a range of potential fire scenarios.
Charring has been identified as the fundamental mechanism through which the structural integrity of timber exposed to fire can be quantified. This thesis investigates the key design criteria of charring rate of timber exposed to a range of heating regimes including standard and non-standard heating. This thesis is novel in it’s use of the custom-built Heat-Transfer Rate Inducing System, developed by Cristian Maluk at the University of Edinburgh, to assess the charring rate of 300mm x 200mm x 120mm Sitka spruce and Scots pine CLT samples. The tests performed as part of this project were intermediate-scale, which avoids the high costs and lack of repeatability associated with repeated furnace testing, while still allowing large samples to be tested.
The CLT was exposed to the following heating regimes: constant heat flux, quadratically increasing heat fluxes and the heat flux from a simulated furnace test (an inverse model to infer incident heat flux from temperature data was developed). These were selected to allow comparison to existing data and standard test methods while exploring the parameter space further.
A novel analysis method was developed to determine the charring-rate as a function of time based on temperature data. The results showed a time-dependent charring rate, which differs from the Eurocode assumption of a constant charring rate model. The average charring rate for tests undertaken using the standard fire curve were found to be around 0.7mm/min (similar to the existing literature, and slightly above Eurocode values), but with significant variation. The constant heat flux tests were compared to similar small-scale tests carried out in the FM Global Fire Propagation Apparatus and it was found that charring rate increases with incident heat flux, and charring is significantly faster on a large, vertically orientated sample than on a small, horizontally orientated sample. It was also observed that charring rate was often not uniform across the sample surface. The results from the quadratically increasing heat fluxes show that charring rate increased linearly with heating rate, with average charring rates increasing from 0.64mm/min at a growth rate of 8.33W/m^2.min to 0.81mm/min at a growth rate of 16.7W/m^2.min, which again differ substantially from the values given in the Eurocodes.
Many congratulations to Alastair!!!