Report
Teaser, summary, work performed and final results
Periodic Reporting for period 2 - FireBar-Concept (MULTI-CONCEPTUAL DESIGN OF FIRE BARRIER: A SYSTEMIC APPROACH)
Teaser
The development of science and technology provides the availability of sophisticated products but concurrently, increases the use of combustible materials, in particular organic materials. Those materials are easily flammable and must be flame retarded to make them safer. In...
Summary
The development of science and technology provides the availability of sophisticated products but concurrently, increases the use of combustible materials, in particular organic materials. Those materials are easily flammable and must be flame retarded to make them safer. In case of fire, people must be protected by materials confining and stopping fire. It is one of the goals of the FireBar-Concept project to design materials and assembly of materials exhibiting low flammability, protecting substrates and limiting fire spread.
The objective of FireBar-Concept is to make a fire barrier formed at the right time, at the right location and reacting accordingly against thermal constraint (fire scenario). This fire barrier can be developed in several ways according to the chemical nature of the material and/or of its formulation:
- Heat barrier formed by inherently flame retarded materials (e.g. mineral fibers, ceramic …) and exhibiting low thermal conductivity (note the assembly of those materials can also provide low thermal conductivity controlling porosity and its distribution)
- Evolution of reactive radicals poisoning the flame and forming a protective ‘umbrella’ avoiding the combustion of the material
- Additives promoting charring of the materials and forming an expanding carbonaceous protective coating or barrier (intumescence)
- Additives forming a physical barrier limiting mass transfer of the degradation products to the flame
The FireBar-Concept project is multidisciplinary and it requires expertise in material science, chemical engineering, chemistry, thermal science and physics. The approach is to make 5 actions linked together by transverse developments: (i) fundamentals of fire barrier, (ii) multi-material and combination of concepts, (iii) modeling and numerical simulation, (iv) design and development of experimental protocols and (v) optimization of the systems.
Work performed
The project started working on the fundamentals of fire barrier and making virtual materials by numerical simulation. The goal is to define the governing parameters of a fire barrier. To support numerical simulation, an experimental bench was designed and built to make comparison between modeling and model material. Several model materials were evaluated including steel, ceramic block, polyisocyaranurate (PIR) foam and intumescent paint. Different numerical models were built taking into account the specific features of the materials (e.g. ablation at the surface of the materials or intumescing materials). The results show the models can capture the specific behavior of the materials such as the ablation of PIR foam upon radiative heating and the intumescence phenomenon. It was possible thanks to novel protocols measuring heat capacity, heat conductivity, thermal diffusivity and estimating kinetic values associated to the decomposition of the material. Those values were measured as a function of temperature of the decomposition degree of the material. Novel in-depth techniques to characterize gaseous and condensed phases of materials/residues issued from fire scenarios are also developing.
In addition to numerical simulation, an innovative small-scale bench was built mimicking different scenario based on jetfire. It is able to a large range of thermal constraints permitting to examine the response of fire barrier in different scenarios. New flame-retardants were also synthesized based on the concept of ‘thermal triggering’ making highly thermally stable structure upon heating.
Final results
The project started 30 months ago. At this stage, our progress beyond the state of the art is
(i) the development of novel protocols to measure thermophysical properties of decomposing materials and taking into account their anisotropic features (if any). It offers a way to characterize materials and to get accurate values to feed numerical models.
(ii) the development of fully instrumented bench-scale test designed to mimic different types of fire scenarios
Website & more info
More info: http://firebarconcept.univ-lille.fr/.