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Izolacijski materiali odigrajo pomembno vlogo pri preprečevanju prehajanja vlage, toplote, zvoka, električnega toka in ostalih količin. Zaradi izrednih lastnosti izolacije, ter tudi ostalih lastnosti, so v industriji in vsakdanjem življenju široko zastopani in uporabljeni. V diplomskem delu sem se osredotočil na gorljivost izolacijskih materialov, standarde s katerimi jih klasificiramo in na preprečevanje razvoja požara in njegovih posledic. Glavna naloga požarno odpornih izolacijskih materialov je preprečitev razvoja požara in njegovega širjenja, ki ključno varuje pred posledicami požara, poleg odsotnosti zadostne temperature vira vžiga in oksidacijskega sredstva. Na podlagi raziskave fizikalnih, kemijskih in termičnih karakteristik v diplomskem delu ugotovimo da izolacijski gradbeni materiali (kamena in steklena volna, penjeno steklo), izolacijske plastične mase (politetrafluoroetilen PTFE, polistiren PS, polieterimid PEI) in izolacijska vlakna (ogljikova vlakna, poliimidna vlakna PI, poliestrska vlakna PES) zagotavljajo visoko primarno funkcijo izoliranja s toplotno prevodnostjo λ < 0,1 W/mK. Poleg tega pa izolacijski materiali s svojimi protipožarnimi lastnostmi zagotavljajo ustrezno stopnjo požarne odpornosti za objekte in predmete saj imajo vsi materiali, z izjemo PS, visoko gostoto, ki omogoči ugodno sestavo materiala. Specifične toplote cp za plastične mase in vlakna zavzemajo vrednosti med 1,1 in 2,0 kJ/kgK, vrednosti specifičnih toplot za gradbene materiale pa so nad 700 kJ/kgK in tako sposobni prevzeti bistveno večje količine toplote. Tališča Tt za plastične mase so pod 500 °C in zato bistveno hitreje tvorijo goreče kapljice za širjenje gorenja kot gradbeni materiali s tališči okoli 1000 °C. Kisikov indeks OI, ki je določljiv samo za plastične mase in vlakna, je za obravnavane materiale nad 25. vol. %, s čimer je izpolnjena sposobnost zaviranja gorenja. V primeru gorenja ali tlenja izolacijskih materialov se sproščajo škodljivi plinasti produkti, ki na organizmu lahko povzročijo trajne poškodbe. Največjo nevarnost prestavljata ogljikov oksid CO in dioksid CO2, ki se tvorita z visokimi deleži pri gorenju vseh vrst materialov, in jih s človeškimi čutili ne zaznamo. Zato z različnimi mehanizmi gašenja, pri čemer sta najbolj učinkovita hlajenje reakcijske cone in dušenje, preprečimo ali omejimo širjenje in vpliv potencialnih nevarnosti v najkrajšem možnem času. Insulation materials play an important role in preventing the translation of moisture, heat, sound, electricity and other quantities. Due to the extraordinary properties of insulation, as well other properties, they are widley represented and used in industry and every day life. In my thesis i focused on flammability of insulation materials, the standards for classification and on the prevention of the development of fire and it's consequences. The main task of fire-resistant materials is to prevent the development of fire and it's spread, which is crucial to protect against the fire consequences, in addition to the absence of sufficient temperature of the ignition source and oxidizing agent. Based on the research of physical, chemical and thermal characteristics in the thesis, insulating building materials (stone and glass wool, foam glass), insulating plastics (polytetrafluoroethylene PTFE, polystyrene PS, polyetherimide PEI) and insulating fibres (carbon fibres, polyimide fibres PI, polyester fibres PES) provide a high primary insulation function with a thermal conductivity λ < 0,1 W/mK. In addition, insulating materials with their fire-retardant properties provide an adequate level of fire resistance for buildings and objects, as all materials, with the exception of PS, have high densities, which allows a favourable composition of the material. Specific heats for plastic and fibres occupy values between 1,1 and 2,0 kJ/kgK, while values for building materials are above 700 kJ/kgK and are able to absorb significantly more heat. Melting point for plastics are below 500 °C, therefore they form flammable droplets for spreading the fire much faster, than building materials with melting points around 1000 °C. The oxygen index, which can only be determined for plastic and fibres, is above 25 vol. %, so they fulfill the ability to inhibit combustion. In the case of burning or smoldering of insulation materials, harmful gaseous products are released, which can cause permanent damage to the organism. The greatest danger is presented by carbon monoxide CO and CO2 dioxide, which are formed with high proportion in the combustion of all materials and are not detected by the humans senses. Therefore, various extinguishing mechanisms are used to prevent or limit the spread of the fire and impact of potential hazards in the shortest possible time. |
