This work is an experimental and theoretical analysis of factors and conditions affecting smoke and carbon monoxide (CO) production in corridor-like enclosure fires. Thirty eight experiments were performed in a three metre long corridor-like enclosure having a cross section 0.5 m x 0.5 m, door-like openings in the front panel and a propane gas burner located near the closed end. Measurements of smoke and carbon monoxide concentrations were performed at locations inside the enclosure and also in the exhaust duct of a hood collecting the combustion products. The main conclusion of this work is that smoke production depends not only on the fuel and Global Equivalence Ratio (GER) - as is reported in the literature - but also on the temperatures and residence time inside the enclosure, at least for the experimental conditions examined in this study. Additionally, it was found that the smoke concentration inside the enclosure was increasing during the ventilation controlled regime even after external burning started. Such increase was verified by temperature, smoke and velocity measurements inside the enclosure. The increase was due to reverse flow behind the flames travelling along the corridor. Namely, the gases reversed direction behind the flames with hot gases travelling in the upper layer backwards towards the closed end of the corridor in contrast to hot gas movements towards the opening in front of the flames. This recirculation was confirmed by velocity and oxygen concentration measurements in the upper and lower layers inside the enclosure. In addition, the present results show that the relationship reported in the literature between smoke and carbon monoxide production during overventilated conditions yco/ys ≈ constant, is no longer valid during an underventilated enclosure fire. The ratio yco/ys increases for the Global Equivalence Ratios of the enclosure greater than one. The obtained results are useful for CFD validation and specifically applicable for assessing smoke hazards in corridor fires in buildings where smoke concentrations can be much larger than anticipated owing to leakage to adjacent rooms behind travelling flames.

This work is an experimental and theoretical analysis of factors and conditions affecting smoke and carbon monoxide (CO) production in corridor-like enclosure fires. Thirty eight experiments were performed in a three metre long corridor-like enclosure having a cross section 0.5 m x 0.5 m, door-like openings in the front panel and a propane gas burner located near the closed end. Measurements of smoke and carbon monoxide concentrations were performed at locations inside the enclosure and also in the exhaust duct of a hood collecting the combustion products. The main conclusion of this work is that smoke production depends not only on the fuel and Global Equivalence Ratio (GER) - as is reported in the literature - but also on the temperatures and residence time inside the enclosure, at least for the experimental conditions examined in this study. Additionally, it was found that the smoke concentration inside the enclosure was increasing during the ventilation controlled regime even after external burning started. Such increase was verified by temperature, smoke and velocity measurements inside the enclosure. The increase was due to reverse flow behind the flames travelling along the corridor. Namely, the gases reversed direction behind the flames with hot gases travelling in the upper layer backwards towards the closed end of the corridor in contrast to hot gas movements towards the opening in front of the flames. This recirculation was confirmed by velocity and oxygen concentration measurements in the upper and lower layers inside the enclosure. In addition, the present results show that the relationship reported in the literature between smoke and carbon monoxide production during overventilated conditions yco/ys ≈ constant, is no longer valid during an underventilated enclosure fire. The ratio yco/ys increases for the Global Equivalence Ratios of the enclosure greater than one. The obtained results are useful for CFD validation and specifically applicable for assessing smoke hazards in corridor fires in buildings where smoke concentrations can be much larger than anticipated owing to leakage to adjacent rooms behind travelling flames.

A smoke explosion is generally considered as a deflagration of the accumulated unburned fuel inside a closed compartment. However, the term smoke explosion has been widely misused for decades with a great deal of confusion, and very little research has been done towards this topic. The purpose of this research is to study the smoke explosion phenomenon in much more detail through the development of a fire scenario under various experimental conditions including ventilation size, fuel elevation and fuel mass, so that a more comprehensive understanding of this phenomenon can be achieved. A total of twenty experiments are carried out including both exploratory and final experiments. Thirteen experiments result in smoke explosions, among which there are five experiments result in more than one smoke explosion. A phenomenon referred as smoldering decay is observed in all experiments with smoke explosions, making it one of the precursors of the smoke explosion phenomenon. The smoldering decay is often indicated by an exponential decay of the temperature and is caused by the low oxygen concentration within the compartment. Based on the analysis, it is found that the vent size must be at least 50 mm in diameter in order for smoke explosions to occur. The fuel elevation has no influence on the occurrence of the smoke explosion. However when the fuel is placed near the ceiling, the temperature, the mass flow rate and the heat release rate are all lowered significantly. The size of the fuel also has no significant influence except for the duration of the experiment. The concentration of CO is scattered in the range of 1.9% and 4.3% when explosions occur. Hence, the accumulation of CO is considered not to be the direct cause for the smoke explosion. The triggering factor for smoke explosions is believed to be the flammable limit formed by the mixture of hydrocarbon and CO. The pressure difference caused by the explosion inside the compartment has to be at least 27 Pa for it to be considered as a smoke explosion.

Thesis (M.S.)--Worcester Polytechnic Institute. / Keywords: heat fluxes; fire testing; composites; instrumentation; material properties. Includes bibliographical references.

Compartment fire scenarios are of great interest due to the large loss of life and property that occurs annually in such fires. Due to the current move towards performance-based building code standards and the increasing acceptance by the regulatory system of model results, there is a growing need for detailed compartment fire data to demonstrate the accuracy of such engineering tools as they are used to ascertain performance. A series of carefully designed full-scale room/corner tests on two vinyl ester resin composite systems have been conducted in a heavily instrumented compartment to provide compartment fire data for the calibration of engineering tools. The two composite systems were chosen based on their thermal behavior. A nominally thermally-thick glass-reinforced plastic (GRP) skin was desirable, as many analytical formulations have been developed using semi-infinite assumptions. A "thermally-thin" skin panel typical of that used in fast ferry construction, consisting of a GRP skin over a balsa core, was also tested. The test protocol used throughout the room/corner experiments was a modification of the ISO 9705 standard where the HRR of the ignition fire was varied according to the Critical Ignition Source Strength concept. To date, there has been little work done where heat fluxes from compartment fires have been measured. Therefore, one of the key data components developed in this series of tests are heat flux measurements from thin skin calorimeters. A total of twenty-five thin skin calorimeters, constructed of Inconel plates, were located throughout the room: the spatial distribution of net and incident heat fluxes within compartment for both pre- and post-flashover conditions have been determined. Additionally, rakes of bare-bead thermocouples were placed in the vent and the corner of the room coincident with the thin skin calorimeter arrays. A third rake was placed in the center of the room. The thermocouple arrays provide data regarding layer temperatures and interface heights as well as a limited determination of temperature spatial distribution within the compartment. The thermocouple rakes also permit calculation of pressure gradients across and mass flows through the vent, thus providing information regarding wall lining fire entrainment rates, of use in corner fire algorithm validations and for globally evaluating the accuracy of CFD codes. Bench-scale cone calorimeter (ASTM E1354, ISO 5660) tests have been carried out on the two composite systems to gather material fire properties necessary as model inputs for fire spread algorithms. The present study developed material properties including heat release rate, species production, and ignition data for the two composite systems. Included are uncertainty bands that account for calculation and instrument uncertainty.

När byggnadsdelars brandmotstånd provas och klassificeras används nästan enbart standardbrandkurvan som definierad temperaturexponering över tid. Brandexponeringen beskrivs i den europeiska standarden EN 1363-1 samt den internationella standarden ISO 834. Standardbrandkurvan definierades för över 100 år sedan i en tid när kunskapen om branddimensionering var bristfällig. Dagens standardbrandkurva är till viss del modifierad men ser i stort sett ut på samma sätt som för 100 år sedan. Ett annat sätt att dimensionera byggnadsdelar på är teoretiskt med hjälp av de parametriska brandkurvorna och materialmodellerna i Eurokoderna. I EN 1991-1-2 bilaga A presenteras en beräkningsmetod, Eurokodmodellen, som resulterar i temperatur-tidkurvor. Denna metod tar hänsyn till hur den slutgiltiga rumsgeometrin och brandlasten ser ut och till skillnad från standardbrandkurvan innehåller den dessutom en avsvalningsfas. Därav anses de parametriska brandkurvorna beskriva verkliga bränder bättre än vad standardbrandkurvan gör. I detta arbete har temperaturutvecklingen i lägenhets- och rumsbränder, baserade på riktiga lägenhetsgeometrier, beräknats med Eurokodmodellen i syfte att jämföra temperatur-tidkurvorna med standardbrandkurvans temperaturexponering. Arbetet påbörjades med en litteraturstudie för att ge en djupare förståelse inom ämnet. Därefter samlades ritningar in från riktiga lägenheter som låg till grund för ett ritningsunderlag. Ritningsunderlaget användes sedan som input till beräkningsmetoden i EN 1991-1-2 bilaga A. För att underlätta beräkningarna skapades ett beräkningsdokument i Excel enligt Eurokodmodellen, där alla beräkningarna genomfördes. Fyra olika scenarier skapades som innefattar två olika termiska trögheter samt två olika öppningsfaktorer för varje termisk tröghet. Anledningen till det var att det ansågs intressant att beakta i vilken utsträckning dessa två parametrar påverkar brandförlopp. Det resulterade i att scenario 3 med lägre termisk tröghet och högre öppningsfaktor var det scenario med kraftigast brandförlopp avseende tillväxthastighet och temperatur. I förhållande till standardbrandkurvan hade majoriteten av temperatur-tidkurvorna för scenario 3 en snabbare upphettningsfas med högre temperaturer fram till påbörjad avsvalningsfas. Scenario 2 med högre termisk tröghet och lägre öppningsfaktor resulterade i det motsatta, det vill säga ett längre brandförlopp med lägre temperaturer. Vid en jämförelse visar det sig att för majoriteten av kurvorna enligt scenario 2, så var temperaturen lägre än standardbrandkurvans under hela brandförloppet. Öppningsfaktorn styr vilken mängd syre som kommer in i brandrummet, en högre öppningsfaktor betyder mer syre och intensivare brandförlopp. Termiska trögheten reglerar hur långsamt brandrummet värms upp, en låg termisk tröghet innebär att brandrummet värms upp snabbare och resulterar därmed i högre temperaturer då mindre energi absorberas av väggarna. De beräknade lägenhets- och rumsbrändernas temperatur-tidkurvor stämde överlag bättre överens med standardbrandkurvan än förväntat. Givet att golv och tak är betong och väggar gips samt att brandlasten som definierats av Boverket är korrekt, är slutsatsen att standardbranden fungerarar bra i de flesta fallen. Dock är tillväxthastigheten i standardbranden lägre i vissa av scenarierna men har i många fall en temperatur vid 60 minuter som överstiger scenariernas. Det finns dock utrymme för utveckling av brandmotståndstester då en mängd av de beräknade lägenhets- och rumsbränderna översteg standardbrandkurvan under tidsperioder på över 30 minuter, något som hade kunnat äventyra de brandskyddstekniska kraven. Men eftersom majoriteten av de beräknade bränderna understeg standardbrandkurvan kan kraven och standardbrandkurvan oftast anses överdimensionerade utifrån genomfört arbete. / When construction parts are tested in order to try and classify the fire resistance, the standard fire curve is almost only used. The standard fire curve defines exposure from temperature over time. The fire exposure is described in the European standard EN 1363-1 and in the international standard ISO 834. The standard fire curve was defined for over 100 years ago, in a time when the knowledge in fire design was inadequate. Now days the standard fire curve is a bit modified, but it almost remains the same as the fire curve defined for 100 years ago. Another way to design construction parts is theoretical by using parametric fire curves and the material models in the Eurocodes. In EN 1991-1-2 appendix A, a method to calculate parametric fire curves is presented, the method results in temperature-time curves and is known as the Eurocode model. This method considers the final room geometry and fire load, it also contains a cooling phase unlike the standard fire curve. Therefore, the Eurocode model is considered to be better at describing real fires. Compartment and room fires based on geometries from real apartments, will be calculated with the Eurocode method in order to compare the temperature-time curves against the exposure of the standard fire curve. The project started with a study of former literature to give a deeper understanding in the current subject. After that, real apartment drawings were collected to represent real apartments. The drawings were then used as input for the calculation method in EN 1991-1-2 appendix A. To calculate in a more effective way an Excel spread sheet was created for the calculation method according to the Eurcode model, which later has been used for all calculations. Four different scenarios were created, including two different thermal inertia and two different opening factors for each thermal inertia. The reason why was that it seemed to be interesting to examine in what extent these parameters affect a fire. It resulted in that scenario 3, the scenario with a lower thermal inertia and a higher opening factor, were the scenario with the fastest growing fire and with the highest temperatures. In comparison with the standard fire curve, scenario 3 had a majority of fires that exceeded the standard fire curve’s temperatures until the cooling phase begun. Scenario 2 which had a higher thermal inertia and a lower opening factor resulted in the opposite, that is a fire burning during a longer time with overall lower temperatures. In comparison with the standard fire curve scenario 2 had a majority of fires with lower exposure of temperature than the standard fire curve, during the entire time of fire. The opening factor controls which amount of oxygen that flows in to the fire compartment, an increase of the amount of oxygen leads to a more intensive fire. The thermal inertia controls how slowly something gets warmed up, a lower thermal inertia means that the fire compartment warms up faster and resulting in higher temperatures as less energy is absorbed by the walls. The calculated compartment and room fires temperature-time curves was in a better agreement with the standard fire curve than expected. Given that the floor and roof is concrete, the walls is gypsum and together with the assumption that the fire load defined by Boverket is correct, is the conclusion that the standard fire works well in most cases. However, the fire growth rate is lower for the standard fire than for some calculated cases but have a temperature at 60 minutes that exceeds most of the calculated cases at the same time. The fire resistance tests can still develop since a big amount of the calculated temperature-time curves exceeded the standard fire curve in periods of time over 30 minutes, something that could affect the fire protection requirements. But the majority of the calculated fires had an exposure of temperature under the standard fire curve. Therefore, the standard fire and the requirements can sometimes be considered oversized based on the work that been done.

Many studies of the fire induced thermal and structural behaviour in large compartments, carried out over the past two decades, show a great deal of non-uniformity, unlike the homogeneous compartment temperature assumption in the current fire safety engineering practice. Furthermore, some large compartment fires may burn locally and they tend to move across entire floor plates over a period of time as the fuel is consumed. This kind of fire scenario is beginning to be idealized as 'travelling fires' in the context of performance‐based structural and fire safety engineering. However, the previous research of travelling fires still relies on highly simplified travelling fire models (i.e. Clifton's model and Rein's model); and no equivalent numerical tools can perform such simulations, which involves analysis of realistic fire, heat transfer and thermo-mechanical response in one single software package with an automatic coupled manner. Both of these hinder the advance of the research on performance‐based structural fire engineering. The author develops an extended travelling fire method (ETFM) framework and an integrated comprehensive tool with high computational expediency in this research, to address the above‐mentioned issues. The experiments conducted for characterizing travelling fires over the past two decades are reviewed, in conjunction with the current available travelling fire models. It is found that no performed travelling fire experiment records both the structural response and the mass loss rate of the fuel (to estimate the fire heat release rate) in a single test, which further implies closer collaboration between the structural and the fire engineers' teams are needed, especially for the travelling fire research topic. In addition, an overview of the development of OpenSees software framework for modelling structures in fire is presented, addressing its theoretical background, fundamental assumptions, and inherent limitations. After a decade of development, OpenSees has modules including fire, heat transfer, and thermo‐mechanical analysis. Meanwhile, it is one of the few structural fire modelling software which is open source and free to the entire community, allowing interested researchers to use and contribute with no expense. An OpenSees‐based integrated tool called SIFBuilder is developed by the author and co‐workers, which can perform fire modelling, heat transfer analysis, and thermo-mechanical analysis in one single software with an automatic coupled manner. This manner would facilitate structural engineers to apply fire loading on their design structures like other mechanical loading types (e.g. seismic loading, gravity loading, etc.), without transferring the fire and heat transfer modelling results to each structural element manually and further assemble them to the entire structure. This feature would largely free the structural engineers' efforts to focus on the structural response for performance-based design under different fire scenarios, without investigating the modelling details of fire and heat transfer analysis. Moreover, the efficiency due to this automatic coupled manner would become more superior, for modelling larger structures under more realistic fire scenarios (e.g. travelling fires). This advantage has been confirmed by the studies carried out in this research, including 29 travelling fire scenarios containing total number of 696 heat transfer analysis for the structural members, which were undertaken at very modest computational costs. In addition, a set of benchmark problems for verification and validation of OpenSees/SIFBuilder are investigated, which demonstrates good agreement against analytical solutions, ABAQUS, SAFIR, and the experimental data. These benchmark problems can also be used for interested researchers to verify their own numerical or analytical models for other purposes, and can be also used as an induction guide of OpenSees/SIFBuilder. Significantly, an extended travelling fire method (ETFM) framework is put forward in this research, which can predict the fire severity considering a travelling fire concept with an upper bound. This framework considers the energy and mass conservation, rather than simply forcing other independent models to 'travel' in the compartment (i.e. modified parametric fire curves in Clifton's model, 800°C‐1200°C temperature block and the Alpert's ceiling jet in Rein's model). It is developed based on combining Hasemi's localized fire model for the fire plume, and a simple smoke layer calculation by utilising the FIRM zone model for the areas of the compartment away from the fire. Different from mainly investigating the thermal impact due to various ratios of the fire size to the compartment size (e.g. 5%, 10%, 25%, 75%, etc.), as in Rein's model, this research investigates the travelling fire thermal impact through explicit representation of the various fire spread rates and fuel load densities, which are the key input parameters in the ETFM framework. To represent the far field thermal exposures, two zone models (i.e. ASET zone model & FIRM zone model) and the ETFM framework are implemented in SIFBuilder, in order to provide the community a 'vehicle' to try, test, and further improve this ETFM framework, and also the SIFBuilder itself. It is found that for 'slow' travelling fires (i.e. low fire spread rates), the near‐field fire plume brings more dominant thermal impact compared with the impact from far‐field smoke. In contrast, for 'fast' travelling fires (i.e. high fire spread rates), the far‐field smoke brings more dominant thermal impact. Furthermore, the through depth thermal gradients due to different travelling fire scenarios were explored, especially with regards to the 'thermal gradient reversal' due to the near‐field fire plume approaching and leaving the design structural member. This 'thermal gradient reversal' would fundamentally reverse the thermally‐induced bending moment from hogging to sagging. The modelling results suggest that the peak thermal gradient due to near‐field approaching is more sensitive to the fuel load density than fire spread rate, where larger peak values are captured with lower fuel load densities. Moreover, the reverse peak thermal gradient due to near‐field leaving is also sensitive to the fuel load density rather than the fire spread rate, but this reverse peak value is inversely proportional to the fuel load densities. Finally, the key assumptions of the ETFM framework are rationalised and its limitations are emphasized. Design instructions with relevant information which can be readily used by the structural fire engineers for the ETFM framework are also included. Hence more optimised and robust structural design under such fire threat can be generated and guaranteed, where we believe these efforts will advance the performance‐based structural and fire safety engineering.

Nous avons abordé dans ce travail deux aspects particuliers de la mécanique des fluides appliquées à la conception des matériels de lutte contre l’incendie. Le premier concerne la ventilation lors du traitement des compartiments. Nous avons montré qu’une grille alvéolaire, placée devant l’hélice du ventilateur, nous permet de façonner le jet et de lui donner une forme ovalisée. Cette forme est plus adéquate à l’entrant du compartiment et permet un gain important de la performance de ces ventilateurs. Le deuxième aspect de ce travail a été de concevoir un système de dosage d’émulseur dans un réseau d’eau sous pression. Nous avons pour cela défini un doseur de type venturi, équipé d’une ogive conique au niveau du col. Cette ogive, dont la position est définie par le rapport entre la pression d’entrée et la pression de sortie. Nous avons montré, à partir du théorème de Bernoulli, que ce système permet de maintenir une aspiration au niveau du col, quelle que soit la pression ou le débit le traversant. / In this work we have analysed two topics of fluid mechanics, applied to the design of fire fighting equipment. The first one is the performance of ventilation during the movement of air in a compartment that contains a fire. We have shown that specific blade angle designed within the gril and placed in front of the fan propeller, allows us to manipulate the jet of air giving it an oval shape. This shape is more efficient and allows a significant gain in the air movement performance within the compartment for these fans. The second aspect of this work was to define an emulsifier dosing system in a pressurized water system. We define a venturi dosing system with a movable cone piece. The position of this conical piece is Controlled by the pressure ratio between the inlet and the outlet. Based on Bernoulli's theorem, we have demontrated that this system maintains a level of suction at the Inlet regardless of the pressure or flow passing through it.

An understanding of compartment fire behaviour is important for fire protection engineers. For design purposes, whether to use a prescriptive code or performance based design, life safety and property protection issues are required to be assessed. The use of design fires in computer modelling is the general method to determine fire safety. However these computer models are generally limited to the input of one design fire, with consideration of the complex interaction between fuel packages and the compartment environment being simplified. Of particular interest is the Heat Release Rate, HRR, as this is the commonly prescribed design parameter for fire modelling. If the HRR is not accurate then it can be subsequently argued that the design scenario may be flawed. Therefore the selection of the most appropriate fire design scenario is critical, and an increased level of understanding of compartment behaviour is an invaluable aid to fire engineering assumptions. This thesis details an experimental study to enhance the understanding of the impact and interaction that the size and location of pool fires within an enclosure have upon the compartment fire behaviour. Thirty four experiments were conducted in a reduced scale compartment (½ height) with dimensions of 3.6m long by 2.4m wide by 1.2m high using five typical ventilation geometries (fully open, soffit, door, window and small window). Heptane pool fires were used, located in permutations of three evenly distributed locations within the compartment (rear, centre and front) as well as larger equivalent area pans located only in the centre. This thesis describes the experimental development, setup and results of the experimental study. To assist in the classification of compartment fire behaviour during the experiments, a ‘phi’ meter was developed to measure the time dependent equivalence ratio. The phi meter was developed and configured to measure O₂, CO₂ and CO. The background development, calibration, and experimental results are reported. A review of compartment fire modelling using Fire Dynamics Simulator, has also been completed and the results discussed. The results of this experimental study were found to have significant implications for Fire Safety Engineering in that the size of the fire is not as significant as the location of the fire. The effect of a fire near the vent opening was found to have a significant impact on compartment fire behaviour with the vent located fuel source increasing the total compartment heat release rate by a factor of 1.7 to that of a centrally placed pool fire of the same total fuel area. The assumption that a fire located in the centre of the room provides for the highest heat release rate is not valid for post-flashover compartment fires. The phi meter was found to provide good agreement with the equivalence ratio calculated from total compartment mass loss rates, and the results of FDS modelling indicate that the use of the model in its current form can not be applied to complex pool fire geometries.