University of Exeter funding: Geography - PhD

Can charring help us better understanding energy fluxes in structural fires and their effect on the structural integrity of timber Geography - PhD (Self-Funded) Ref: 3207

About the Research Project


Prof Claire Belcher, Department of Geography, University of Exeter and leader of the Wildfire Lab

Project information
In many countries wood is used extensively for construction and has uses both structurally and as surface linings. Use of wood is also increasing in use as a sustainable and environmentally friendly building material for a range of structures, even in high-rise buildings.

The nature and rate of charring of exposed wood and exposed structural timbers is critical to understand because it determines how quickly the size of a load-bearing section decreases to a critical level. Hence there are three failure design criteria for fire resistance testing: Stability, Integrity and Insulation.
Here the structural element must be capable of carrying the load of the building for the duration of the fire, whilst integrity and insulation relate to how the fire might be best contained to prevent large scale fire spread throughout a structure.

Work by Prof Belcher and her team in the wildFIRE Lab has shown that the structure of char changes throughout the duration of a fire. This project will aim to consider to what extent micro-scale structural changes in the char scale-up to influence the residual loadbearing capacity of timber units.

The current guidelines for estimating the changes to the structural strength of timber following pyrolysis is based on changes to timber cross section thickness compared to the thickness of the resulting char layer  (Eurocode2). Where the thickness of a char layer is related to to the time of exposure to heat at an assumed constant charring rate. However, wood does not char at a constant rate, this rate depends on the heat release rate the timber is exposed to throughout the lifetime of pyrolysis in an individual fire and varies between fires as well as the timber product itself.

This research will seek to gain a better understanding of how variations in fire behaviour and the density of fuel, its moisture, grain and sample orientation, influence pyrolysis and the formation of a char layer. The aim being to 1) better understand the variations in structural integrity of supporting timber structures that might result when large fires occur in the built environment and 2) consider whether the physical changes in char structure that occur during pyrolysis should be taken into account in current design guidelines (e.g. eurocode 2)

The successful candidate will undertake a range of well controlled laboratory experiments that explore the influence of different heating regimes on the formation and structural integrity of char layers in a range of wood types both natural and man-made composite materials. These will be undertaken using fire-testing equipment based in the U. Exeter wildFIRE Lab  The char samples will be analysed using a unique approach that measures the amount of light reflected back through the profile of a char layer to determine variations in its integrity.

You should have experience in structural engineering, ideally fire safety engineering and be comfortable with understanding heat transfer during fires to structural elements. You must also be capable of designing and undertaking experiments in controlled laboratory conditions both according to existing Standard protocols e.g. ISO/ASTM and those of your own design.

For more information about the project and informal enquiries, please contact the primary supervisor, Claire Belcher

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Entry requirements

You should have or expect to achieve at least a 2:1 Honours degree from a UK university, or equivalent, in an Engineering based science ideally fire safety engineering.

If English is not your first language you will need to meet the English language requirements and provide proof of proficiency.  Click here for more information and a list of acceptable alternative tests.

How to apply

You will be asked to submit some personal details and upload a full CV, covering letter and two academic references. Your covering letter should outline your academic interests, prior research experience and reasons for wishing to undertake this project. You may also be asked to upload verified transcripts of your most academic qualification.

Please quote reference 3207 on your application and in any correspondence about this project.



Application deadline:7th January 2019
Value:This project is self funded
Duration of award:Not applicable
Contact: PGR Enquiries