3D-printing is a new and upcoming manufacturing technique that can significantly reduce time and material losses in production. Fused deposition modeling (FDM) is one of the most commonly used 3D-printing methods for processing conventional thermoplastic polymers. To reduce the printing time and usage of material via FDM technology, a user typically specifies infill density. Therefore, it is important to understand how this printing parameter affects the fire and mechanical properties of the 3D-printed object.  This study aims to investigate the effect of various infill densities on mechanical and fire properties of polylactic acid (PLA) composites produced by FDM 3D-printing technology. PLA composites of five different infill densities were 3D-printed: 20%, 40%, 60%, 80% and 100%. The samples for all tests were designed in AutoCAD and then imported into the slicing software, Ultimaker Cura. The 3D-printer used for printing was the Ultimaker S3 which uses FDM technology. To test the fire and mechanical behavior of 3D-printed PLA composites three tests were conducted: cone calorimeter test, tensile test and UL-94 flammability test. The cone calorimeter testing was done using the incident radiation of 35 kW/m2. The results showed that the trend of HHR curves of all infill densities are akin to each other, though the peak heat release rate and total heat released increases with higher infill density. Time to ignition was also longer for samples with higher infill density. Tensile testing was conducted according to the ASTM D638 standard. The results showed that with increasing infill density mechanical properties improved, with 100% infill density having the highest tensile strength (58.15 MPa) and elastic modulus (1472.1 MPa). From the UL-94 test results no difference in flammability could be observed. Every sample had no rating, which implies that PLA specimens of all infill densities are very flammable, with long afterflame and heavy flammable dripping. The study concludes that among the examined infill densities, no ideal percentage of infill density could be found. Requirements based on application will determine what infill density is most appropriate. Nevertheless, the data collected can hopefully provide a useful reference in designing and manufacturing 3D-printed PLA composites.

In recent years, interest in sustainability and being environmentally friendly has increased. Wood is a durable and renewable building material, which is becoming more common in the constructions industry. In 2002, the government in Sweden adopted a national strategy to promote an increased use of wood in buildings. However, the usage of wood in construction has a potential risk – wood is ignitable and has fire-spreading properties.  The aim of this project was to investigate whether a ZnO coating can reduce the risk of ignition on wooden surfaces exposed to a radiative heat source, focusing on the time to ignition of the wood. ZnO possess a wide combination of physical properties, such as ability to reflect infrared radiation and being thermally stable at extremely high temperatures. The study has been carried out through a literature review and laboratory experiments. In the laboratory experiments, a cone calorimeter was used and the tests were performed according to ISO 5660-1. In the cone calorimeter, two different amounts of ZnO applied to the wood surface were tested, 0.5 and 1 g ZnO per dm2 and an untreated piece of wood as a reference. The test was carried out in three different heat fluxes: 20, 35 and 50 kWm-2. After completed tests, the change in the wood’s morphology was examined in a scanning electron microscopy (SEM). The result shows that an application of ZnO on a wooden surface significantly increases the time to ignition for the wood. An application of 0.5 g ZnO per dm2increased the time to ignition by 26-33 % for the three different heat fluxes. On the other hand, 1 g of ZnO per dm2 created an increase of 37-40 %. The trend of the increase of time to ignition was similar for all heat fluxes. The result showed no clear tendency that the smoke production rate was reduced with the application of ZnO. The heat release rate was not affected by the addition of ZnO, which was expected because ZnO delays the time to ignition, but once it catches fire, the wood burns. The SEM images before and after combustion showed that there is no change in the morphology of ZnO, although some ZnO has agglomerated but remains intact after combustion. The conclusion of this study is that ZnO has the potential to protect wood from fireby increasing the time to ignition. But when the wood has ignited, there is no clear tendency for ZnO to affect the growth of the fire. The study has shown that in the future ZnO could be applied to a wooden surface to reduce the risk of fire ignition. Further studies are required to find effective methods to implement the usage of ZnO, as applying ZnO on vertical wooden surfaces.

"Material property estimation method is developed with 1-D heat conduction model and bounding exercise for Fire Dynamics Simulator (FDS) analysis. The purpose of this study is to develop an unsophisticated tool to convert small scale cone calorimeter data into input data that can be used in computational fluid dynamics (CFD) models to predict flame spread. Specific interests of input data for FDS in this study include thermal conductivity, specific heat, pre exponential factor, activation energy, heat of vaporization. The tool consists of two objects; 1-D model and bounding exercise. Main structure of the model is based on one of the thermal boundary conditions in the FDS, named as “Pyrolysis Model, Thermally-Thick Solid”, in which pyrolysis flux occurs on the surface of the object under radiant heat flux. This boundary condition is adopted because it has the best characteristics in the dynamics of modeling which are subject to our interests. The structure of the model is simple and concise. For engineering point of view, a practical model ought to have such simplicity that saves time and effort. Pyrolysis model in FDS meets this requirement. It is also a part of reason that this study is to develop a computational model which converts a set of data from the cone calorimeter test to a set of input data for FDS. A pyrolysis term on a surface of an object in this boundary condition will be playing an important role regarding a surface temperature and a mass loss rate of the object. Bounding exercise is introduced to guide proper outcome out of the modeling. Prediction of the material properties from the simulation is confirmed by the experimental data in terms of surface temperature history and mass loss rate under the bounding exercise procedure. For the cone calorimeter, thirteen different materials are tested. Test materials vary with their material composition such as thermoplastics, fiber reinforced plastics (FRP), and a wood. Throughout the modeling fed by a set of the cone calorimeter test data, estimated material properties are provided. So called “Bounding Exercise” is introduced here to draw the estimated material properties. Bounding exercise is a tool in order to guide the material property estimation procedure. Three sets of properties (Upper, Standard and Lower) are derived from the boundary exercise as recommended material properties. From the modeling results, PMMA shows the best agreement regarding the estimated material properties compared with already known results from the references. Wood indicates, however, somewhat different results, in which the mass loss rate takes a peak around the ignition and decreases sharply. This burning behavior can not be predicted using the “Pyrolysis Model”. The model in this study does not account so called “Charring Behavior” that a charring layer toward a surface or difference between a charred density in a charring layer and a normal density in a virgin layer of a wood. These factors result in a discrepancy of the estimated material properties with the reference data. Unlike PMMA and wood, FRP materials show a unique ignition characteristic. Mass loss rate history from some FRP materials indicate more a thermoplastic burning behavior and other materials tend to char. In addition there are few known material property data for theses materials and it is difficult to verify the results from this study with pre-existing data. Some plastic samples also indicate difficulties of the modeling. Because some samples melt and disfigure during the test, one dimensional heat transfer boundary condition is no longer applicable. Each bounding exercise results are fully examined and analyze in Chapter 6. Some of limitations contain model’s structural limitation, in which the model is too simple for certain cases, as well as limitations of bounding exercise. Finally, recommendations are made for future work including upgraded model accountable for the pyrolysis of charring material and FRP materials, data comparison with FDS results, and improved bounding exercise method."

<p>The theme of this thesis is the reaction to fire performanceof wood and other building products, andparticularly thematerial fire properties time to ignition, rate of heat releaseand smoke production. These properties have been measured by asmall-scale fire test method, the Cone Calorimeter, andpresented for different types of building products.</p><p>Uncertainty analysis, included instrument and assumptionuncertainty, has been performed for the case that both O2 andCO2 are measured for calculation of the rate of heat release inthe Cone Calorimeter. The partial derivatives for theuncertainty analysis are given. The relative uncertainty forthe rate of heat release measurements in the Cone Calorimeteris between ±5% to ±10% for rate of heat releasevalues larger than about 50 kW/m2.</p><p>The time to ignition in the Cone Calorimeter is compatiblewith the time to ignition in the ISO Ignitability test, whichis the main test method for measuring time to ignition. Thetime to ignition is an increasing linear function of density.The rate of heat release in the Cone Calorimeter is dependentof material thickness and of use of retainer frame. Thematerial thickness gives the heat release curve duration andshape. Thin materials have short burning time and two maximumvalues. Thick materials have long burning time and when thematerial is thicker than about 35 mm no second maximum appears.When the retainer frame is used the actual exposed surface isreduced from 0.01 m2 to 0.0088 m2, the rate of heat release isreduced and the burning time is increased. A comparison ofresults with and without use of the retainer frame gives thenequal results when the exposed area is set to 0.0088 m2 in thecase of using the retainer frame.</p><p>The time to flashover in the full-scale room corner test waspredicted on the basis of Cone Calorimeter data at 50 kW/m2 bya power law of ignition time, the total heat release calculatedover 300 s after ignition and the density of the product. Therelation gives a simple relation to evaluate if a productreaches flashover in the room corner test.</p><p>The smoke production has also been measured in the ConeCalorimeter. The white light and the laser smoke measurementsystems have shown similar results. There is a correlationbetween Cone Calorimeter and room corner test smoke productionwhen the products are divided into groups: those that reachflashover in the room corner test in less than 10 min and thosethat have more than 10 min to flashover. Temperature profilesin wood have been measured in the Cone Calorimeter by a simpletechnique. The effect of fire protective gypsum plasterboardson the charring of wood frame members has been determined andcompared with fullscale furnace wall tests. The protectiveeffects of twenty different boards have been presented. ConeCalorimeter and furnace tests show similar charring of wooduntil the boards fall down in furnace tests. After that, thecharring of wood is higher in the furnace, because the wood isexposed directly to the fire.</p><p><b>Keywords:</b>building products, charring of wood, ConeCalorimeter, fire retardant treated wood, fire tests,ignitability, mass loss, rate of heat release, reaction tofire, smoke production, wood products</p>

The theme of this thesis is the reaction to fire performanceof wood and other building products, andparticularly thematerial fire properties time to ignition, rate of heat releaseand smoke production. These properties have been measured by asmall-scale fire test method, the Cone Calorimeter, andpresented for different types of building products. Uncertainty analysis, included instrument and assumptionuncertainty, has been performed for the case that both O2 andCO2 are measured for calculation of the rate of heat release inthe Cone Calorimeter. The partial derivatives for theuncertainty analysis are given. The relative uncertainty forthe rate of heat release measurements in the Cone Calorimeteris between ±5% to ±10% for rate of heat releasevalues larger than about 50 kW/m2. The time to ignition in the Cone Calorimeter is compatiblewith the time to ignition in the ISO Ignitability test, whichis the main test method for measuring time to ignition. Thetime to ignition is an increasing linear function of density.The rate of heat release in the Cone Calorimeter is dependentof material thickness and of use of retainer frame. Thematerial thickness gives the heat release curve duration andshape. Thin materials have short burning time and two maximumvalues. Thick materials have long burning time and when thematerial is thicker than about 35 mm no second maximum appears.When the retainer frame is used the actual exposed surface isreduced from 0.01 m2 to 0.0088 m2, the rate of heat release isreduced and the burning time is increased. A comparison ofresults with and without use of the retainer frame gives thenequal results when the exposed area is set to 0.0088 m2 in thecase of using the retainer frame. The time to flashover in the full-scale room corner test waspredicted on the basis of Cone Calorimeter data at 50 kW/m2 bya power law of ignition time, the total heat release calculatedover 300 s after ignition and the density of the product. Therelation gives a simple relation to evaluate if a productreaches flashover in the room corner test. The smoke production has also been measured in the ConeCalorimeter. The white light and the laser smoke measurementsystems have shown similar results. There is a correlationbetween Cone Calorimeter and room corner test smoke productionwhen the products are divided into groups: those that reachflashover in the room corner test in less than 10 min and thosethat have more than 10 min to flashover. Temperature profilesin wood have been measured in the Cone Calorimeter by a simpletechnique. The effect of fire protective gypsum plasterboardson the charring of wood frame members has been determined andcompared with fullscale furnace wall tests. The protectiveeffects of twenty different boards have been presented. ConeCalorimeter and furnace tests show similar charring of wooduntil the boards fall down in furnace tests. After that, thecharring of wood is higher in the furnace, because the wood isexposed directly to the fire. Keywords:building products, charring of wood, ConeCalorimeter, fire retardant treated wood, fire tests,ignitability, mass loss, rate of heat release, reaction tofire, smoke production, wood products / <p>NR 20140805</p>

No description available.

This study describes an approach to determine the thermal conductivity of wood at elevated temperatures. The aim is to be able to use the developed conductivity as input in structural elements in finite element calculations. The conductivity of pine wood and glue laminated timber with different densities and moisture contents have been evaluated where small scale one-dimensional laboratory trials have been carried out in a cone calorimeter. Steel temperatures were measured behind the exposed wood samples. Obtained temperatures from the experimental trials have been compared with back calculated steel temperatures in the finite element program TASEF (Temperature Analysis in Structures Exposed to Fire). In the back calculations the conductivity at 100 °C, 300 °C and 500 °C was altered in order to achieve a best fit steel temperature curve as the measured ones during the experimental trials. At 20 °C the conductivity was taken from the literature. Between these temperature levels the conductivity was assumed to vary linearly. The dehydration of the moisture content in the wood samples have been considered by including it in the specific volumetric enthalpy, i.e. the integral over temperature of the density and specific heat as input in the temperature calculation program TASEF. Regarding the thermal degradation, recommended formulas in Eurocode 5: Design of timber structures – Part 1-2: General – Structural fire design, have been applied. The final back calculated conductivity values of the studied pine wood at specific temperatures (20 °C, 100 °C, 300 °C och 500 °C) were determined by the cone calorimeter test to be as follows; 0.09 W/mK, 0.07 W/mK, 0.05 W/mK and 0.35 W/mK. Comparing with presented conductivity of wood in Eurocode 5 the developed conductivity in this study are generally lower. Derived conductivity values from the back calculations in TASEF have been reconsidered for the glue laminated timber by taken account of differences in density and moisture content. By using a developed conversion factor, so called “conductivity ratio”, new conductivity values could be obtained which then has been used as an input in TASEF. As a result, good similarities between calculated steel temperatures and measured steel temperatures could be seen. The implemented method, consisting of simple one-dimensional laboratory trials for determining the thermal conductivity is deemed to be promising.  However, further studies are needed to be done in order to increase the accuracy of the method.

Lors du déclenchement d’un incendie en milieu clos, la quantité d’oxygène du local décroît, entrainant une combustion incomplète. Des gaz chauds imbrûlés peuvent alors s’accumuler dans le local ou dans les gaines de ventilation et un accident thermique peut survenir suite à un apport d’air frais. Ce travail, réalisé pour AREVA, vise à quantifier et d’analyser ce risque, afin de pouvoir le prédire et le prévenir. Tout d’abord, une étude bibliographique a été réalisée afin de définir les paramètres d’auto-inflammation à partir du modèle de Frank-Kamenetskii. Celui-ci permet, après un bilan d’énergie, l’établissement d’un paramètre critique, δC, d’auto-inflammation du mélange. δC réunit la géométrie, la température (et la température ambiante) et la composition du mélange à l’auto-inflammation.Puis, la dégradation thermique du Polyéthylène Haute Densité en fonction de la densité surfacique de flux incident à la surface du matériau et de la sous-ventilation a été caractérisée (cinétique de dégradation, productions gazeuses). Le Cône Calorimètre à Atmosphère Contrôlée a été employé.Ce travail expérimental a permis d’obtenir plusieurs mélanges gazeux suivant les conditions. La dernière partie de l’étude a permis, à partir de δC, de poser le volume de mélange via le rayon comme critère d’auto-inflammabilité des mélanges. En imposant une température, en faisant varier la fraction volumique de chaque gaz combustible entre sa LII et LSI le risque d’accident thermique a été défini. / After the beginning of a fire in a closed room, the oxygen rate in the atmosphere decreases. This implies an incomplete combustion and unburnt gases production. These ones may accumulate in the room or in ventilation pipes, and, after mixing with fresh air, auto-ignite. This could trigger a thermal accident such as backdraft. This present work, conducted for AREVA, aims to analyse this hazard and provide some methods to predict and prevent it. First, a bibliographical research, was carried on to define a mixture’s auto-ignition parameters. This study was based on Frank-Kamenetskii’s model: after establishing the energetics balance between the heat produced by combustion, and the one consumed by conduction, an auto-ignition critical parameter, δC, was defined. It reunites the system’s geometry, temperature (or the room temperature) and composition.Then, the High Density Polythene degradation in a Controlled Atmosphere Cone Calorimeter was studied. The effect on the material’s degradation of under-ventilation and of the energy brought has been tested through the oxygen concentration in the atmosphere and the incident heat flux.During this work many different gas mixtures were analyzed. On the ground of δC formula, the final step was to set the volume, through the radius (characteristic size of the system), as an auto-ignition parameter. Making the concentration of each combustible varying between the LFL and UFL and imposing the temperature allowed to predict this hazard.

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.

Due to their outstanding properties, poly(arylene ethers) are useful as toughness modifiers in epoxy resins (EP). Furthermore, these polymers show rather low intrinsic fire risks. According to recent research it has been incorporated that poly(arylene ether phosphine oxides) [PAEPO’s] can further improve the fire behavior. Increasing phosphorous content of the PAEPO can influence the fire behavior too. Fire retardants containing phosphorus – regardless of whether an additive or reactive approach is used – show different mechanisms in the condensed and gas phase. In the present study PSU Control (BPA based polysulfone) with four different PAEPO’s and their corresponding blends with an EP were investigated. All poly(arylene ether phosphine oxides) were synthesized by nucleophilic aromatic polycondensation. The polymers obtained covered a wide range of weight average molar masses (6,000 – 150,000 g/mol) as determined by size exclusion chromatography with multi-angle light scattering detection (MALLS). FTIR, NMR spectroscopy and MALDI-TOF revealed formation of the desired polymer structure of the linear poly(arylene ethers). All polymers were easily soluble in common organic solvents, thus enabling processing from solution.The pyrolysis and the fire retardancy mechanisms of the polymers and blends with epoxy resin (EP) were tackled by means of a comprehensive thermal analysis (thermogravimetry (TG), TG-evolved gas analysis) and fire tests [PCFC, limiting oxygen index (LOI), UL-94, cone calorimeter]. The Mitsunobu reaction of Dimethyl-5-hydroxyisophthalate and a long chain semifluorinated alcohol requires triphenyl phosphine as a reactant. Identical, in some case higher yield was obtained in the usual conditions, with triphenyl phosphine and with trivalent phosphorus containing polymers, which was prepared in solvent free bulk (melt) polymerization technique from trivalent phosphorus monomer and a silylated diphenol in presence of CsF. Purification and the recovery of the final product which is always a big challenge in case of Mitsunobu reaction, was far more easier using polymer compared to triphenyl phosphine. During polymerization there was a possibility to have polymer having repeating unit containing both trivalent phosphorus and phosphine oxide. The trivalent phosphorus content of the polymer can be varied using different molar concentration of CsF.