The size of a soot particle has an effect on smoke detector alarm activation. It is the purpose of this paper to identify changes to soot particle size and examine if those size changes effect smoke detector alarm times in the ceiling jet. Changes in particle size has been attributed to delays in detector activation, however, little evidence exists to support that particle size changes occur in the ceiling jet where detector activation occurs. This paper presents the results from laser scattering experiments and calculations conducted to support and validate the experimental findings. The laser scattering from various aerosols was collected, over time, to examine changes in particle size due to agglomeration in the smoke aging process. The laser scattering measurements were made at two linear polarizations, vertical (VV) and horizontal (HH), and scattering angles ranging from 20 to 155 degrees. A laser with a wavelength of 632.8 nm was used as a light source. The aerosol laser scattering results were then compared to the results from the Mie scattering theory. The Mie scattering theory was adjusted using a lognormal distribution to generate theoretical light scattering curves expected from a polydisperse aerosol typical of smoke. The collected data was examined using a combination of the Mie theory with various particle sizing techniques, including dissymmetry ratio and polarization ratio, to look for changes in laser scattering indicating changes in particle size.

"Alternate models for extended ceiling convection heat transfer and ceiling vent mass flow for use in the Harvard Computer fire Code are developed. These models differ from current subroutines in that they explicitly consider the ceiling jet resulting from the fire plume of a burning object. The Harvard Computer fire Code (CFC) was used to compare the alternate models against the models currently used in CFC at Worcester Polytechnic Institute and with other available data. The results indicate that convection heat transfer to the ceiling of the enclosure containing the fire may have been previously underestimated at times early in the fire. Also, the results of the ceiling vent model provide new insight into ceiling vent phenomena and how ceiling vents can be modeled given sufficient experimental data. this effort serves as a qualitative verification of the models as implemented; complete quantitative verification requires further experimentation. Recommendations are also included so that these alternate models may be enhanced further. "

"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."

This study is designed to provide the composites industry as well as the fire engineering industry baseline data for pyrolysis modelling of common fiber reinforced polymer (FRP) systems. Four resin systems and three glass contents will be considered. This matrix of FRP systems has been carefully fabricated and documented so as to provide“transparency" as to the system compositions. An important and interesting aspect of these FRP systems is that all the resins used are listed by the manufacturers as Class 1 or Class A per ASTM E 84. The FRP systems are being evaluated in bench scale modern fire test apparatuses (FPA, ASTM E 2058, and Cone, ASTM E 1354); detailed information on the FPA is provided. These apparatuses provide a range of measurements such as heat release rate that can be used to calculate engineering“properties" of these FRP systems. The“properties", such as minimum heat flux for proper ignition (found to range from 20 to over 100 kW/m2) and the b flame spread parameter, can then be used to compare the fire performance (flashover potential) of these FRP systems according to resin type and glass content. Additional instrumentation has also been added to the specimens to allow surface and in-depth temperatures to be measured. The additional measurements are used to complete a set of data for pyrolysis modelling and for calculating thermal properties of the composites. The effect of environment oxygen concentration and flaming and non-flaming decomposition are investigated in terms of fundamental pyrolysis behavior of the FRP systems. A general conclusion is that the phenolic composite has better fire engineering“properties" than the polyester composite but the glass is the controlling component of the composite with regards to temperature profile and resulting thermal properties.

The potential hazard of fire is one of the major concerning issues after the recent events of 9/11 and others. A lot of studies and research work is being carried out presently, to ensure the safety of buildings. But, there is no accurate method to estimate the fire endurance/resistance for a building due to the variability of fire characteristics, material properties of construction material, and other characteristics of a building. One can only provide guidelines and can adopt from the lessons learnt in the past to ensure better quality to make the buildings more fire proof, so that they can withstand high temperatures and stresses for a longer time, before collapse mechanism occurs. From a long time, live laboratory tests have been conducted to study the performance of assemblies by subjecting them to appropriate time-temperature histories that are derived from standardized fire curves. The performance-based approach is very time consuming and also involves high costs. In recent times, due to the advances in technology, computer models have been developed, that aid towards the simulations of assemblies and other components of a building that are subjected to a fire event. This approach helps in attaining reasonable results, thereby providing an alternative to the prescriptive and performance-based approaches. This project deals with the study of heat transfer mechanism that takes place in steel structures in case of a fire event. For proper and accurate simulation process, the use of software is a must along with the support of technical resources. Due to high thermal conductivity of steel the heat gets transferred rather fast in the steel section which creates non-uniform temperature distributions because of variable thermal properties, like thermal conductivity and specific heat. 3-D finite element software TAS (Thermal Analysis Software) was used to study the non-uniform temperature distributions in case of a W 12x27 beam protected with vermiculite coating. The results were compared with the studies done by Professor Bletzacker, which involved the furnace testing of a W 12x27 beam by subjecting it to ASTM E-119 curve time-temperature history. In addition to this, the sensitivity of results was evaluated based on the variation of thermal properties for concrete, vermiculite, and gypsum board. Different beam models for W12x27 section protected with vermiculite and gypsum board coatings were simulated to justify their performance based on temperature rise within the assembly. Also, simulations were performed for analyzing the behavior of the beam when subjected to different fire curves like ASTM E-119 and ENV. Analytical analysis was also carried out using the method of Lumped mass parameter method to provide a comparison of results from different models. Finally, conclusions and recommendations were made to ensure further development and understanding in the field of Structural and Fire Protection Engineering.

Flamskyddande kemikalier används idag inom en hel del olika områden. Ett stort område är textil, där hemtextil är dominerande. Det finns en mängd olika typer av flamskydd på marknaden. Alla har till uppgift att sakta ner brandförloppet eller helt förhindra att en brand uppstår. De halogenerade flamskydden är de mest effektiva men har många kopplingar till miljöproblem. De fosforbaserade och kvävebaserade är snällare mot miljön med mindre effektiva än de halogenerade. Ofta kombineras de fosfor- och de kvävebaserade flamskydden för att få bättre egenskaper på slutprodukten.Denna rapport innehåller, på uppdrag av FOV Fabrics AB, en kartläggning av flamskyddsmarknaden i Europa, med fokus på de produkter som kan tillämpas på material av polyester och polyamid. Målet är att finna flamskyddsmedel för dessa som dessutom är tvättbeständiga samt relativt ofarliga för miljön. De produkter som anses relevanta testas sedan gentemot den internationella brandstandarden, ISO 6941, vilket innebär att en provbit belagd/impregnerad med kemikalien fästs vertikalt i en anordning. Tygprovet utsätts sedan för en horisontell låga i tio sekunder. Därefter görs mätningar på exempelvis den tid det tar tills tygprovet slocknat, samt andel skadat material. Rapporten innehåller även information om övriga tester som utförts, såsom drag- och rivstyrka, tvättbeständighet och färgförändringsmätningar på de produkter som visat tillfredsställande resultat i brandtesterna.Av de nio produkter vi testade fann vi varierade resultat. En del uppfyllde inte våra krav med avseende på flamskydd, och en del visade sig ha mycket dålig tvättbeständighet. Vi fann dock några produkter för båda materialen, två för polyester och fyra för polyamid, som är aktuella att göra vidare tester på. Eventuellt kvävs justering av koncentrationer och appliceringsrutiner för att möta FOV:s önskemål.Flame-retardant chemicals are used today in a lot of different areas. A large area is textiles, where upholstery textiles are dominant. There are many different types of flame retardants on the market, and the purpose is to slow down or completely prevent a fire. The halogenated flame retardant is the most effective but has many links to environmental problems. The phosphorous and nitrogen-based is kinder to the environment but often with less efficiency than the halogenated. When phosphorous and nitrogen flame retardants are combined, the two often get better features.This report, commissioned by the company FOV Fabrics AB, contains a scan of the flame retardant market in Europe, focusing on those products that can be applied to textiles of polyester and polyamide. The goal is to find the flame retardant for these materials, which are also wash resistant and has a relatively low environmental impact. The products that are deemed relevant are then tested against the international fire standard, ISO 6941, which means that a test piece, which has been coated/finished with the chemical, is fastened vertically on a device and then ignited by a horizontal flame for ten seconds. Thereafter, measurements are taken as regards to the amount of time before the test piece burns out and the proportion of damaged material. The report also includes information about other tests conducted, such as tensile- and tear strength, wash resistance and color change. These measurements are made on those products which have shown satisfactory performance in regards to the fire tests.Among the nine products we tested, we found varied results. Some did not meet our requirements for fire protection, and some were found to have very poor wash resistance. We found, however, a couple of products for polyester and four products for polyamide which showed such good results that they are relevant for further testing. Adjustment of concentration and application procedures may be adjusted to achieve the requirements of FOV's specifications. / Program: Textilingenjörsutbildningen

Vätgas är en energibärare som kan vara en av pusselbitarna i omställningen till en mer klimatneutral värld. Infrastrukturen byggs ut, industrin växer och vätgasfordon blir vanligare. Vätgas är ett ämne med de bra egenskaperna att det kan lagra kemisk energi och från förnybar el tillverkas med elektrolys, men det har också den riskabla egenskapen att det är mycket brandfarligt. Vid läckage av vätgas finns risken att en jetflamma med höga temperaturer uppstår vilket påverkar omgivningen där det sker. Standarder för jetbrandtester är idag baserade på tester med propan, men då vätgas har andra egenskaper behövs ökad kunskap för att minska riskerna vid olyckor. Studien syftar till att via litteraturstudier samla information om storskaliga jetbrandtester, vilken utrustning som används, hur material påverkas av jetflammor och vilka standarder som finns för jetflammor och jetbrandtester. Ett av syftena är också att med intervjustudie ta reda på hur räddningstjänsten i Luleå ser på utvecklingen av vätgasinfrastruktur och om de har några rutiner för olyckor med vätgas. Det finns en vision vid Luleå tekniska universitet att det i framtiden ska finnas en anläggning för att utföra jetbrandtester av vätgas och andra bränslen i Luleå. Studien syftar därför också till att via intervju ta reda på om räddningstjänsten i Luleå skulle ha någon användning för en sådan anläggning. Jetbrandtester kan enligt standarden SS-ISO 22899-1:2021 utföras i mindre skala med propan som bränsle och ändå ge liknande resultat som vid storskaliga jetbrandtester med naturgas. Jetbrandtestet utförs för att testa brandmotstånd genom integritet (E) och isolerande förmåga (I) för passiva brandskyddsmaterial som används till rör, paneler, konstruktionsstål och rör- och kabelgenomföringar. Testerna utförs enligt standarden med utrustning såsom munstycke, åter-cirkuleringskammare, skyddskammare, med mera. Enligt standarden SS-ISO 22899-1:2021 träffas testobjektet vid ett jetbrandtest med en jetflamma av propan på 1 meters avstånd. Det korta avståndet medför att propanet inte fullt hinner förbrännas vilket skapar temperaturskillnader på testobjektets yta när det träffas av flamman. Det bildas en ”kall” och en ”varm” zon på ytan där den ”kalla” zonen är den punkt som i direkt kontakt med jetflamman utsätts för mekanisk kraft i form av erosion. För vätgas hinner flamman stabilisera sig på en meters avstånd vilket gör att testobjektet träffas av en fullt utvecklad flamma och därför både utsätts för termiska laster i form av en enhetlig ”varm” zon och mekaniska laster i form av erosion. Denna skillnad kan göra att passiva brandskyddsmaterial vid jetflammor av vätgas inte klarar av att upprätthålla det krav på brandmotstånd som ställs. Detta är främst aktuellt att undersöka för reaktiva passiva brandskyddamaterial då de är mer känsliga för erosion än icke-reaktiva passiva brandskyddsmaterial. Om så är fallet att passiva brandskyddsmaterial inte klarar av att motstå jetflammor av vätgas lika bra som för propan kanske en standard för jetbrandtester med vätgas skulle behöva tas fram. Det kan vid intervjun med PärJohan Fredrickson som är sektionschef för myndighetsutövningen vid Luleå räddningstjänst konstateras att de verkar vara väl informerade om utvecklingen av vätgasinfrastrukturen och att de har varit delaktiga i vätgasfrågor sedan några år tillbaka. De har samarbeten med andra räddningstjänster och de försöker tidigt vara med i dialogen när nya processer och verksamheter utvecklas. De har i dagsläget inte några operativa övningar med jetflammor av vätgas men de arbetar förebyggande genom att ta fram insatsplaner tillsammans med de industriella verksamheter som hanterar vätgas. De kan från ett förebyggande perspektiv se hur räddningstjänsten kanske skulle kunna ha användning av en anläggning för att genomföra jetbrandtester med vätgas. Men om det finns något operativt behov behöver vidare utredas med personal på räddningstjänsten som arbetar inom de operativa resurserna. / Hydrogen is an energy-carrier that can be a piece in the change for a climate neutral world. The infrastructure and industry expand, and hydrogen vehicles becomes more common. Some good characteristics with hydrogen are that it from renewable energy can be produced through electrolysis and store chemical energy, but it also has the risky characteristic that its very flammable. If hydrogen gas would leak from a container there is the risk of a jet flame with high temperatures that can affect the surroundings. Today’s standards for jet fire testing are based on propane gas, but because hydrogen has so many different characteristics there might be a need for more knowledge to prevent risks and accidents. Through a literature study this report aims to gather information about large scale jet fire testing, what equipment that is used, how materials react to jet flames, and what standards that are current for jet fire testing and jet flames. A purpose is to through an interview-study figure out how the rescue service in Luleå sees on the development in hydrogen infrastructure and if they have any routines for accidents with hydrogen. Luleå University of Technology has a vision to in the future have a facility in Luleå where they can perform jet fire testing with hydrogen and other flammable fuels. One purpose of the study is therefore to interview the rescue service in Luleå to investigate if they would have any interest in such facility and what use they could have of it. According to the standard SS-ISO 22899-1:2021, jet fire tests with propane gas can be performed in a smaller scale and still give similar results as for large scale jet fire tests with natural gas. The jet fire test is performed to determine the fire resistance regarding integrity (E) and isolating capacity (I) for passive fire protection materials that are used for pipes, panels, structural steelwork, and pipe penetration seals. The gear that is used for the tests are a nozzle, flame re-circulation chamber, protective chamber etc. A propane flame hits the object of testing from 1 meter according to the standard. Because of the short distance, the propane flame does not reach full combustion which leads to a temperature difference on the object of testing that is encountered with the jet flame. A “cold” and “hot” zone is therefore created at the surface where the “cold” zone appears at the center core of the jet flame. At this core, the object of testing is exposed to a higher mechanical force in terms of erosion than other parts of the object. For hydrogen the jet flame stabilizes in 1 meter which changes how the flame affects the object of testing. The object is instead hit by a fully combusted jet flame that exposes it to high thermal load with a uniform “hot” zone and mechanical load of erosion. That difference could change how passive fire protection (PFP) materials are able to resist jet flames with hydrogen as the tests for PFP materials are done with propane. This would mainly be topical for reactive PFP materials as they are more sensitive to erosion than non-reactive PFP materials and a standard for jet fire tests with hydrogen may become relevant if PFP materials fail to maintain the requirements that are set for propane. The interview with section manager PärJohan Fredrickson that works at Luleå rescue service shows that Luleå rescue service seems to be well informed about the development of hydrogen infrastructure. Since a few years back they have been involved with questions relating to hydrogen, they have collaborations with other rescue services around the country and they try to get involved as early as possible when new processes and operations are formed. They do not seem to do any exercises where they train for jet fire accidents with hydrogen involved but they are working to prevent accidents with hydrogen. Action plans has been and are being developed together with the operations that are handling the hydrogen. The rescue service could from a preventive perspective have a use of a facility for jet fire testing with hydrogen. But it must be further investigated if there is an operative need to use such a facility.

"The fire resistance of structural building elements has become an increasing concern after the terrorist attacks on September 11th, 2001. This concern has pushed for changes in the building codes and standards to incorporate a performance-based approach to design. Performance-based design is a process where fire safety solutions are determined using a representation of the actual fire stages that may occur in a structure during a fire event. The American Institute of Steel Construction (AISC) has added Appendix 4 in the Specification for Structural Steel Buildings to the current edition of the Steel Construction Manual to provide engineers with guidance in designing steel structures and components for fire conditions. The performance-based approach outlined in Appendix 4 is designed to prevent loss of life, structural collapse, and the outbreak of fires through elimination of ignition sources. Adopting this approach, requires structural engineers to have a better understanding of the behavior of steel connections under fire conditions as well as the tools, techniques and judgment for analysis. The focus of this thesis is to study the strength behavior of steel connections under fire conditions with the assistance of the finite element software, ALGOR. Connections of varying thickness and bolt patterns are constructed using the ALGOR pre-processing software. A time-temperature fire curve is combined with external loads, applied to the models and then analyzed in the program. Stress-strain diagrams are created using the results and yield loads are determined for the various connections at normal and elevated temperatures. These yield loads are compared to values found from a mathematical analysis of the limit state equations in Chapter J of the Specifications. The elevated models are created with temperature-dependent material properties, therefore the yield loads are associated with critical temperatures within the connection models. It is found that the capacity and governing temperature of the connections is determined by the limit state of bearing at the bolt hole. At elevated temperatures, the finite element analysis produces capacities significantly lower than the analysis at normal temperatures. "

Despite advancements in the development of synthetic fibers and materials that provide better insulation, fire ground burn injuries remain a significant issue. The current test methods for fire fighting clothing were investigated to determine their adequacy in evaluating the actual performance of clothing materials. This investigation uncovered several potential problems with the current test methods. A series of new, small scale, tests were used to evaluate the shortcomings of the current test methods and develop possible improvements. A small test apparatus, designed and donated by Ktech Corporation, was used to measure the thermal properties (thermal conductivity and volumetric heat capacity) of a series of fire fighting clothing materials. The thermal properties were estimated for single fabric layers, as well as ensembles, with various levels of moisture added to simulate actual end use conditions. In addition, a skin simulant sensor was used to assess the time to 2nd degree burn for exposures similar to those required in current standards for fire fighting clothing. A one dimensional heat conduction model was developed to predict the time to 2nd degree burn for the skin simulant sensor protected with outer shell materials that may be used as wildland fire fighting clothing, using the thermal property data obtained from earlier tests. An alternative method was developed to calculate the time to 2nd degree burn for ensembles evaluated with the new skin simulant sensor. The predictions for the time to 2nd degree burn obtained from the new skin simulant sensor were compared against results obtained using the sensor specified in the current test methods. The predictions for the skin simulant sensor were consistently shorter than those from the current test sensor. The current test sensor predictions for the time to 2nd degree burn were nominally 40% to 50% higher than the predictions from the skin simulant sensor during the evaluations of outer shell materials.

Fire statistics suggest that there is an urgent need for improved performance of light-weight truss construction in fire scenarios. This thesis proposes the use of Fire Retardant Treated Wood (FRTW). Several floor truss systems were designed for a residential living room using sawn lumber and FRTW. A finite difference, heat transfer model was used to determine time to collapse and to identify modes of failure during a simulated exposure to the standard ASTM E-119 test fire curve. As part of ongoing research at WPI, this is an initial effort to use analytical methods in the study of heat transfer and structural performance of wood construction during fire conditions. Results were examined for important relationships to further advance the understanding of collapse mechanisms in wood trusses. Experimental procedures for further testing have also been developed. Acknowledgment that in-service conditions may alter structural fire performance is made and the implications are discussed. An alternate fire scenario, more representative of residential fire loading, was also developed and compared to the ASTM E-119 fire curve.