Konstruktionsbränder kan idag orsaka stora problem för räddningstjänsten. Släckningsarbeten vid konstruktionsbränder brukar idag involvera släckmedel som bygger på vattenbaserade medel. Detta medför att primära skador kan begränsas, men istället uppstår problemet med sekundära skador som mögel eller vattenskador. Idag finns det flertalet släckmedel som används men det finns inga dokumenterade tillfällen där flytande kväve och/eller koldioxid används vid konstruktionsbränder. Branschen har istället funnit användningsområden för flytande kväve vid gruvbränder med flertalet lyckade insatser. Flytande kväve och koldioxidsläckare är båda kylande släckmedel som vid användning uppnår mycket låga temperaturer. Släckmedlen släcker på liknande sätt, båda kyler till en viss del, men den primära släckkällan är kvävning. Flytande kväve får en avsevärd volymutveckling vid fasövergång från flytande till gas. Gasen tränger undan syret i den brandhärjade konstruktionen och kan därmed släcka branden. Koldioxid verkar på samma sätt, kvävande, men i detta fall övergår den kondenserade gasen till fast fas (torr-is) vid aktivering som sedan sublimerar till gas och kväver branden. För att undersöka släckmedlens förmåga att bekämpa konstruktionsbränder samt återantändningsskyddet vid användning, har åtta konstruktioner byggts. De fristående konstruktionerna ska efterlikna ett regelfack från en väggkonstruktion. Vid försöken har fyra konstruktioner använts till att undersöka flytande kväve och fyra konstruktioner för att undersöka koldioxid. Av dessa åtta användes två som testkonstruktioner i syftet att bestämma metod för applicering av släckmedel och anläggning av brand i konstruktionen. För att anlägga en brand i konstruktionerna antändes de i det nedre högra hörnet med hjälp av en propanbrännare. Vid fyra försök applicerades släckmedlen i mitten av konstruktionen i ett hål som borrats för att nå innandömet. Vid de andra två konstruktionerna applicerades släckmedlen vid hålet där branden anlades. För att mäta de temperaturer som uppstod i konstruktionerna placerades fem termoelement i varje konstruktion. I de tre försök där flytande kväve applicerades sjönk temperaturen drastiskt och efter en timme, när försöken avslutades, registrerade inget termoelement temperaturer höga nog för att en återantändning skulle kunna ske. I de tre försök där koldioxid applicerades släcktes två av tre konstruktioner och den tredje återantändes. Fem av sex försök uppvisades en trend där temperaturen låg mellan 12 – 56 °C när försöken avslutades och där temperaturen fortfarande sjönk. En trend påvisades för bägge släckmedlen, där de dröjde kvar i konstruktionen när försöken avslutades, efter cirka en timme. Släckmedlen kunde därmed under en lång tid förångas och påverka den brandhärjade konstruktionen och motverka återantändning. Slutsatsen av detta projekt är att flytande kväve och koldioxid verkar lovande som släckmedel vid konstruktionsbränder. Fler försök bör dock utföras för att styrka resultatet innan ett välgrundat uttalande kan göras. / Today structural fires can cause big problems for the rescue services. Extinguishing structural fires usually depends on methods involving water based extinguishers. These methods entails that the primary damages can be limited although secondary damages like mold or water damage may arise. Today there are several fire extinguishers that are used in the industry but few documented occasions have been found where liquid nitrogen or carbon dioxide is used on structural fires. Liquid nitrogen has long been used for mining fires with success. What liquid nitrogen and carbon dioxide in extinguishers have in common is that they are both cooling agents which upon activation reach very low temperatures. These extinguishing agents both put out a fire in a similar way, they both chill when applied, but that is not the primary source. The primary source of extinguishing comes by suffocating the fire by removing all the surrounding oxygen. The volumetric growth of gas between phase transitions displaces the oxygen present in the fire ravaged construction and thereby extinguishes the fire. Eight constructions were built to test these extinguishing agents and their potential for extinguishing construction fires. The purpose of these constructions was to simulate one part of an entire wall. To perform these tests, four out of the eight constructions were used to examine liquid nitrogen and the other four were used for carbon dioxide fire extinguishers. Two constructions were used as test constructions with the purpose to test different methods for the extinguishing agents as well as setting fire to the construction. A propane burner was used in the lower right corner of the construction to ignite it. The extinguishing agents were applied to the center of the constructions in four tests. In two tests the extinguishing agents were directed at the base of the fire in the lower right corner. A total of thirty thermocouples were used, divided evenly among the six tests that recorded data, with five thermocouples being placed in each construction. In the three tests with liquid nitrogen as extinguishing agent, the temperature dropped drastically. The temperatures registered in the wall by the thermocouples were not high enough to pose any risks for a fire to resurface at the end of the tests. In the tests using carbon dioxide as an extinguishing agent the fire managed to resurface in one out of three tests. In five out of six tests the thermocouples registered temperatures in the range of 12 – 56 °C and continually declining. Both of the extinguishers displayed similar behavior when observed, namely that the extinguishing medias could be observed remaining in the constructions long after the tests ended. This means that the extinguishing agents could evaporate during an extended period of time and counteract any flames from resurfacing. To conclude this report, the good qualities these extinguisher agents exhibit implies that they work well as extinguishing agents to combat construction fires. More experiments should be performed to strengthen the results from this project.

Os incêndios estão presentes na história de várias cidades do mundo e, em algumas delas, chegaram a protagonizar mudanças significativas no desenho urbano e nas características construtivas de suas edificações. No Brasil, o conhecimento sobre segurança contra incêndio em edificações só se tornou assunto de importância após duas grandes tragédias nacionais: os incêndios nos edifícios Andraus (em 1972, com dezesseis mortos) e Joelma (em 1974, com cento e oitenta e nove mortos), ambos na cidade de São Paulo. Atualmente, após a tragédia ocorrida na boate Kiss em Santa Maria - RS em 2013, que culminou com a morte de 242 jovens, muitas alterações nas legislações estaduais de proteção contra incêndio estão sendo sugeridas no Congresso Nacional e nas Assembleias Legislativas Estaduais, porém, em sua maioria, sem respaldo científico e normativo. Juntamente com as mudanças legislativas, muitos produtos e equipamentos surgem diariamente com o objetivo de proteger a vida humana e o patrimônio histórico e cultural. Nesse sentido, surgem as proteções passivas por tintas intumescentes que, conforme se verifica com os resultados desse trabalho, possuem a propriedade de manter o conforto e isolamento térmico adequados, além de manter a resistência a compressão e capacidade máxima de carga dos blocos cerâmicos de vedação em níveis aceitáveis pela norma brasileira, após a exposição direta a chama durante um período de 60 minutos. / Fires are present in the history of cities around the world, and some of them came to star in significant changes in urban design and the construction characteristics of their buildings. In Brazil, the knowledge Fire Safety in buildings only became a matter of importance after two great national tragedies: fires in Andraus buildings (in 1972, with sixteen dead) and Joelma (in 1974 with one hundred eighty-nine dead) both in São Paulo. Currently, after the tragedy at Kiss nightclub in Santa Maria - RS in 2013, which culminated in the death of 242 young people, many changes in state laws fire protection are being suggested in Congress and in State Legislative Assemblies, however, in mostly without scientific and regulatory support. Along with legislative changes, many products and equipment appear daily in order to protect human life and the historical and cultural heritage. In this sense, there are passive protections for intumescent coatings that, as evidenced by the results of this work, have the property to maintain comfort and thermal insulation appropriate, while maintaining resistance to compression and maximum load capacity of sealing ceramic blocks at acceptable levels by the Brazilian standard, after direct exposure to flame for a period of 60 minutes.

Made available in DSpace on 2017-06-01T17:57:36Z (GMT). No. of bitstreams: 1 carlos_alexandre_santos_sales.pdf: 4056461 bytes, checksum: 353a15499589396f6deff6860ff0459e (MD5) Previous issue date: 2016-03-30 / Fires are present in the history of cities around the world, and some of them came to star in significant changes in urban design and the construction characteristics of their buildings. In Brazil, the knowledge Fire Safety in buildings only became a matter of importance after two great national tragedies: fires in Andraus buildings (in 1972, with sixteen dead) and Joelma (in 1974 with one hundred eighty-nine dead) both in São Paulo. Currently, after the tragedy at Kiss nightclub in Santa Maria - RS in 2013, which culminated in the death of 242 young people, many changes in state laws fire protection are being suggested in Congress and in State Legislative Assemblies, however, in mostly without scientific and regulatory support. Along with legislative changes, many products and equipment appear daily in order to protect human life and the historical and cultural heritage. In this sense, there are passive protections for intumescent coatings that, as evidenced by the results of this work, have the property to maintain comfort and thermal insulation appropriate, while maintaining resistance to compression and maximum load capacity of sealing ceramic blocks at acceptable levels by the Brazilian standard, after direct exposure to flame for a period of 60 minutes. / Os incêndios estão presentes na história de várias cidades do mundo e, em algumas delas, chegaram a protagonizar mudanças significativas no desenho urbano e nas características construtivas de suas edificações. No Brasil, o conhecimento sobre segurança contra incêndio em edificações só se tornou assunto de importância após duas grandes tragédias nacionais: os incêndios nos edifícios Andraus (em 1972, com dezesseis mortos) e Joelma (em 1974, com cento e oitenta e nove mortos), ambos na cidade de São Paulo. Atualmente, após a tragédia ocorrida na boate Kiss em Santa Maria - RS em 2013, que culminou com a morte de 242 jovens, muitas alterações nas legislações estaduais de proteção contra incêndio estão sendo sugeridas no Congresso Nacional e nas Assembleias Legislativas Estaduais, porém, em sua maioria, sem respaldo científico e normativo. Juntamente com as mudanças legislativas, muitos produtos e equipamentos surgem diariamente com o objetivo de proteger a vida humana e o patrimônio histórico e cultural. Nesse sentido, surgem as proteções passivas por tintas intumescentes que, conforme se verifica com os resultados desse trabalho, possuem a propriedade de manter o conforto e isolamento térmico adequados, além de manter a resistência a compressão e capacidade máxima de carga dos blocos cerâmicos de vedação em níveis aceitáveis pela norma brasileira, após a exposição direta a chama durante um período de 60 minutos.