Novel fire testing frameworks for Phase Change Materials and hemp-lime insulation
Abstract
Modern buildings increasingly include the usage of innovative materials aimed at improving
sustainability and reducing the carbon footprint of the built environment. Phase Change
Materials (PCMs) are one such group of novel materials which reduce building energy
consumption. These materials are typically flammable and contained within wall linings yet
there has been no detailed assessment of their fire performance. Current standard fire test
methods provide means to compare similar materials but do not deliver knowledge on how
they would behave in the event of a real fire. Thus, the aim of this thesis is to develop a novel
testing framework to assess the behaviour of these materials in realistic fire scenarios.
For PCMs, a flammability study is conducted in the bench-scale cone calorimeter to evaluate
the fire risk associated with these materials. Then, micro-scale Thermogravimetric Analysis
(TGA) is used to identify the fundamental chemical reactions to be able to confidently
interpret the flammability results. Finally, intermediate-scale standard fire tests are conducted
to evaluate the applicability of the bench-scale results to realistic fire scenarios. These take the
form of modified Lateral Ignition and Flame spread Test (LIFT) and Single Burning Item (SBI)
tests to understand flame spread and compartment fires respectively. Finally, a simplified
method to combine this knowledge for use in building design is proposed. This method allows
the balancing of potential energy benefits with quantified fire performance to achieve the
specified goals of the designer.
Hemp-lime insulation is a material which has also becoming increasingly popular in the drive
towards sustainability. The porous nature of the material means that smouldering
combustions are the dominant reaction mode but there is currently no standardised test
method for this type of behaviour. Thus, hemp-lime materials also represent an unquantified
risk. The work in this thesis defines a simple, accessible and economically viable bench-scale
method for quantifying the fire risk associated with rigid porous materials. This is applicable
for both downward opposed flow and upward forward flow smoulder propagation
conditions. The behaviour is then interpreted using micro-scale thermogravimetric analysis to
understand the underlying pyrolysis and oxidation reactions. Designers can utilise this
framework to quantify the smouldering risk associated with hemp-lime materials to enable
their usage in the built environment.
The holistic fire risk assessment performed in this thesis has quantified the behaviour of PCMs
and hemp-lime insulation applicable to realistic fire scenarios. The simplified design method
empowers designers to be able to realise innovative buildings through fundamental
understanding of the fire behaviour of these materials. The outcomes of this thesis allow
designers to mitigate the fire risk associated with these materials and achieve optimised
engineering solutions. Furthermore, the novel fire testing frameworks provide the
economically viable means to assess the fire performance of future PCMs and hemp-lime
products which ensures lasting relevance of this research in the future.