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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
21

Assessment of Passive Fire Protection on Steel-Girder Bridges

Davidson, Michael 01 December 2012 (has links)
Bridges in the US are severely damaged or suffer collapse from fires at significant rates, even when compared to other hazards such as earthquakes. Fire-induced bridge collapses are perpetuated by the general lack of installed fire protection systems. Therefore, new materials and applications are needed to mitigate structural damage that can be caused to civil infrastructure by severe fires. Accordingly, the objective of this study is to further the development of new fire protection applications in transportation structures. Specifically, the investigation centers on the development of new applications in passive fire protection materials, within the context of shielding steel-girder bridges against severe fire effects. A steel-girder bridge has been selected for study, and a high-resolution finite element model has been formed based on the corresponding bridge structural drawings. Temperature-dependent structural material properties and thermal properties have been synthesized and incorporated into the model. Additionally, a representative fire scenario has been formed (in part) based on a recent fire incident that occurred at the selected bridge site. The fire scenario also incorporates the characteristics of a fully loaded gasoline tank truck fire, where a means of incorporating the severe fire into the finite element model (as thermal loading) has been identified and enacted. Coupled thermal-mechanical finite element analyses have been carried out using the (unprotected) steel-girder bridge model. An additional finite element simulation has been carried out, where the steel-girder bridge model has been fitted with a refractory cement material that insulates the underside of the bridge spans. Also, a finite element simulation has been carried out where the steel-girder bridge model has been fitted with intumescent coating material as insulation against fire effects. Both the refractory cement and the intumescent coating materials have been found to possess robust insulation characteristics from the simulation results. Namely, the finite element analysis results indicate that, in the event of a bridge fire, both materials are capable of preventing the buildup of damaging temperatures in underlying structural members. Accordingly, the refractory cement and intumescent coating materials have been identified as successful passive fire protection materials for the fire scenario and bridge case considered.
22

Gravity model to detect forest fire prone areas in the southeast fire district of Mississippi

Sadasivuni, Raviraj, January 2007 (has links)
Thesis (M.S.)--Mississippi State University. Department of Geosciences. / Title from title screen. Includes bibliographical references.
23

Novel fire testing frameworks for Phase Change Materials and hemp-lime insulation

McLaggan, Martyn Scott January 2016 (has links)
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.
24

Modeling of Electrical Cable Failure in a Dynamic Assessment of Fire Risk

Bucknor, Matthew D. 17 September 2013 (has links)
No description available.
25

Příprava staveb a BOZP / Preparation of Construction and OSH

Vaculík, Jakub January 2022 (has links)
This study investigates the management of a construction project from the building contractor’s point of view. The main aim is to describe the construction readiness process, including the technical drawings, risk assessment and OSH solutions. The literature review provides an overview of the key terminology used in the management of a construction site, contractor readiness and OSH. The practical section of this study then describes order preparation, construction readiness, risk assessment, OSH solutions and fire risk assessment for the I/43 Milonice intersection turn lane.
26

Fuel load characterisation and quantification for the development of fuel models for Pinus patula in South Africa

Ross, Timothy Ian 12 1900 (has links)
Thesis (MScBosb)--University of Stellenbosch, 2004. / ENGLISH ABSTRACT: The characteristics and total fuel load of the forest floor (FF) and harvest residue (HR) are needed to develop tools that can be used for fuel load management, fire risk analysis and fire behaviour prediction for P. patula grown in the summer rainfall area of South Africa (SA). Forest floor depth, mass and ash-free mass were measured and there was generally a greater range in depth under sawtimber (ST) stands than under pulpwood (PLP) stands. Forest floor loads, prior to ashing, ranged from 21 - 168 t ha-1 and 27 - 72 t ha-1, for ST and PLP stands, respectively and loads increased linearly with stand age. Sawtimber and PLP stands were analysed together, which resulted in a significant correlation between depth and mass (r2 = 0.78, n = 31). A loss on ignition procedure carried out on sub-samples of the FF improved the relationship between the FF depth and the ash-free mass for the different stands, and provided a more accurate model for the prediction of mass from depth. A multiple regression analysis revealed that age, altitude and mean annual precipitation (MAP) provided the best subset and accounted for 72% of the variation in the FF mass observed. The effect of increasing FF load and increasing moisture content on the fireline intensity (FLI) was examined using the fire behaviour prediction programme, BehavePlus. Harvest residue was quantified and characterised in terms of fuel size classes, under current silvicultural regimes for ST and PLP, for the development of fuel models for this species over its planted range in SA. An investigation into the proportion (by mass) of the 1- (0.0 - 0.6 cm), 10- (0.6 – 2.5 cm), 100- (2.5 – 7.6 cm) and 1000-hr (> 7.6 cm diameter) fuel classes of the total HR mass indicated that there was a significant difference between the mass of the 1-, 10- and 1000-hr fuel classes of the two silvicultural regimes, and no significant difference for the 100-hr fuel class. Two fuel models for P. patula HR and two models for standing timber were developed using the new model (NEWMDL) programme of BEHAVE and tested in BehavePlus. Nutrient concentrations were used with FF layer and HR size class load data to estimate the quantities of nutrients held in the fuel and to describe nutrient distributions in the fuel complex. Significant differences in the nutrient concentration of the FF layers and fuel components were observed which has important implications for fuel management. The concentration of N determined in this study, relative to that determined in other similar studies on P. patula was low. Forest floor loads were predicted and nutrient pools calculated for typical ST and PLP stands at both low and high altitude to provide insight into the nutrient distributions within the fuel complex. / AFRIKAANSE OPSOMMING: Die karaktereienskappe en totale brandstoflading van die bosvloer (FF) en kaalkap oorskot (HR) word benodig om instrumente te ontwikkel wat gebruik kan word vir brandstoflading bestuur, brandgevaar ontleding en brandgedrag voorspelling vir P. patula, wat in die somer reënvalgebied van Suid-Afrika groei. Die bosvloer diepte, massa en asvrye massa is gemeet en daar was oor die algemeen ‘n groter variasie in diepte onder saaghout (ST) opstande as onder pulphout (PLP) opstande. Die bosvloerladings, voor verassing, het varieer van 21 – 168 t ha-1 en 27 – 72 t ha-1 vir ST en PLP opstande respektiwelik. Ladings het linieêr vermeerder met opstand ouderdom. Saaghout en PLP opstande is saam geanaliseer en het tot ‘n betekenisvolle korrelasie gelei tussen diepte en massa (r2 = 0.78, n = 31). ‘n Verliestydens- ontbranding prosedure is uitgevoer op die FF monsters en het die verhouding tussen FF diepte en die asvrye massa van die verskillende opstande verbeter. Dit het ook gelei tot akkurater model vir die voorspelling van massa vanaf diepte. ‘n Veelvoudige regressie analise het aan die lig gebring dat ouderdom, hoogte en gemiddelde jaarlikse reënval (MAP) die beste sub-groep verskaf, en het 72% van die variasie in die FF massa verklaar. Ondersoek is ingestel op die effek van toenemende FF lading en toenemende voginhoud op die brandlyn intensiteit (FLI) deur die brandgedrag program, BehavePlus, toe te pas. Die kaalkap oorskot is gekwantifiseer en gekarakteriseer volgens brandstof grootteklasse, onder die huidige boskultuurstelsels vir ST en PLP, vir die ontwikkeling van brandstofmodelle vir hierdie spesie oor die betrokke groeistreek in SA. ‘n Ondersoek in die verhouding (volgens massa) van die 1- (0.0 – 0.6 cm), 10- (0.6 – 2.5 cm), 100- (2.5 – 7.6 cm) en 1000-uur (> 7.6 cm deursnee) brandstofklasse van die totale HR massa het aangedui dat daar ‘n betekenisvolle verskil is tussen die massas van die 1-, 10- en 1000-uur brandstofklasse van die twee boskultuurstelsels, en geen betekenisvolle verskil vir die 100- uur brandstofklas nie. Twee brandstofmodelle is ontwikkel vir P. patula HR en twee modelle vir staande hout deur gebruik te maak van die nuwe model (NEWMDL) program van BEHAVE en getoets in BehavePlus. Voedingstof konsentrasies is gebruik, tesame met die FF laag en HR klasgrootte ladingdata, om die voedingstof inhoud van die brandstof te skat en om die voedingstof verspreiding te beskryf in die brandstofkompleks. Betekenisvolle verskille is waargeneem in die voedingstof konsentrasies van die FF lae en brandstof komponente wat belangrike implikasies inhou vir brandstofbestuur. Die konsentrasie wat vir N in hierdie studie bepaal is, was laag relatief tot ander soortgelyke studies vir P. patula. Die bosvloer ladings is voorspel en voedingstofpoele bereken vir tipiese ST en PLP opstande vir beide lae en hoë hoogtes om insig te verkry, sodat insig verkry kon word in die voedingstof verspreidings binne die brandstofkompleks.
27

Mapping the potential of veld fire occurrence in the mountain regions of the South Western Cape, using GIS

Akinnusi, Olamigoke Adekunle 04 1900 (has links)
Thesis (MSc)--Stellenbosch University, 2003. / ENGLISH ABSTRACT: Veld fires in the mountain regions of the South Western Cape are an annual occurrence. These veld fires occur as a result of human, natural and unknown causes. The Mediteranean weather conditions of the South Western Cape and its typical vegetation are conducive to these fires. Within the mountain regions of the South Western Cape, the use of fire can be advantageous for conservation and forest managers as a tool for fire management e.g. preparation of fire belts, reduction of veld fire occurrence by burning fuel load, rejuvenation of indigenous vegetation and enhancing the water yield of surrounding areas within their management area. Abnormally high incidences and run away veld fires within the management area of conservation and forest managers leads to. the loss of biodiversity, destruction of properties and loss of human lives, and extensive soil erosion. This study aimed at identifying factors contributing towards the occurrence of veld fires in the mountain regions of the South Western Cape, and using GIS to analyse spatially the contributing variables, and to generate seasonal veld fire hazard maps. Potential veld fire occurrence on a seasonal basis was mapped using spatial analyses of variables that are significant to the distribution of veld fires within the study area. Variables used to assess potential veld fire occurrences were: vegetation, slope, population density (human influence), proximity to roads, mean monthly maximum temperatures and mean monthly rainfall. The veld fire hazard maps generated indicated that potential for veld fire occurrence is high in the summer and autumn months, decreasing to a low in the winter and spring seasons. The exception is the Southern Cape sub-region where the possibility of veld fires can be quite high in winter as a result of Fohn-like berg winds. These winds are characterized by sudden increases in temperature and decreases in humidity that may pose severe fire hazards. Reducing and containing veld fires in the mountain regions of the South Western Cape depends on the effective use of the seasonal veld fire hazard maps. The maps can be used to delineate critical zones of veld fire occurrence which can be used for evaluating costeffective control measures and can be implemented to reduce the level of veld fire danger within the management areas of conservation and forest managers. There is a need for a Catchment Management System (CMS) (Richardson, Van Wilgen, Le Maitre, Higgins & Forsyth, 1994) that can be used to generate daily probabilities of veld fire occurrence and to link these to fire-spread models for predicting or simulating expected fire directions and severities or intensities, and educating people about fires and the damage it can do. / AFRIKAANSE OPSOMMING: Elke jaar kom daar veldbrande in die berggebiede van die Suidwes-Kaap voor. Die oorsake van hierdie veldbrande is van menslike, natuurlike of onbekende oorsprong. Die Mediterreense weersomstandighede en die tipiese plantegroei van die Suidwes-Kaap is ook bevorderlik vir die ontstaan van veldbrande. In die berggebiede van hierdie streek kan die gebruik van vuur egter ook tot voordeel van natuurbewaring en bosbou aangewend word deurdat dit gebruik kan word as 'n metode om die brande te bestuur, soos in die voorbereiding van brandpaaie, in die vermindering van die voorkoms van veldbrande deur vooraf van die brandbare materiale af te brand, in die vernuwing van die inheemse plantegroei en in die verhoging van wateropbrengs in die omliggende gebiede binne die area wat bestuur moet word. 'n Abnormale hoë voorkoms van veldbrande binne die bestuursgebied van bewarings- en bosboubestuurders lei egter tot 'n verlies aan biodiversiteit, die vernietiging van eiendom, 'n verlies aan menselewens en uitgebreide gronderosie. Die doel van hierdie studie was om die faktore wat bydra tot die voorkoms van veldbrande in die berggebiede van die Suidwes-Kaap te identifiseer, om GIS te gebruik om 'n ruimtelike analise van die bydraende veranderlikes te doen en om dan 'n seisoenale veldbrandgevaarkaart saam te stel. Die potensiële voorkoms van veldbrande op 'n seisoenale basis is gekarteer deur gebruik te maak van ruimtelike analises van die veranderlikes van belang in die verspreiding van veldbrande in die studiegebied. Die volgende veranderlikes is gebruik om die potensiële voorkoms van veldbrande te bepaal: plantegroei, helling, bevolkingsdigtheid (invloed van mense), afstand vanaf paaie, gemiddelde maandelikse maksimum temperature en gemiddelde maandelikse reënval. Die veldbrandgevaarkaarte wat ontwikkel is, het aangetoon dat die potensiële voorkoms van veldbrande hoog is in die somer- en herfsmaande en dan afneem tot 'n laagtepunt in die winter en lente. 'n Uitsondering is die Suid-Kaap-substreek waar die moontlikheid van veldbrande selfs in die winter taamlik hoog is as gevolg van Fëhn-tipe bergwinde. Hierdie winde word gekenmerk deur In skielike toename in temperatuur en In afname in humiditeit wat die brandgevaar skerp kan verhoog. Die vermoë om veldbrande in die berggebiede van die Suidwes-Kaap te verminder en te beperk, sal grootliks afhang van die effektiewe gebruik van die seisoenale veldbrandgevaar-kaarte. Die kaarte kan gebruik word vir die afbakening van kritieke sones vir die voorkoms van veldbrande wat dan gebruik kan word vir die evaluering van koste-effektiewe beheermaatreëls. Hierdie kaarte kan dan geïmplementeer word om die vlakke van veldbrandgevaar binne die gebiede waarvoor bewarings- en bosboubestuurders verantwoordelik is, te verminder. Daar is In behoefte aan In opvanggebiedbestuurstelsel (OGB) (Richardson, Van Wilgen, Le Maitre, Higgins & Forsyth 1994) wat gebruik kan word om daaglikse waarskynlikhede vir die voorkoms van veldbrande te genereer. Dit kan gekoppel word aan brandverspreidingsmodelle wat die verwagte rigting van brandverspreiding, asook die ems of intensiteit daarvan, kan voorspelof simuleer. Die publiek moet ook ingelig word oor veldbrande en die skade wat daardeur aangerig kan word.

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