Study On Fire Safety Of Building Exterior Insulation System Based On Fire Prevention Barrier

With the developing of society and technology,the energy lack occurs,which makes the energy saving building getting vast development space.The exterior thermal insulation system of building external wall is an important component of the energy saving building.Some specific test procedures,standards,and criterions about testing the durability and efficiency of the exterior thermal insulation system have been developed with the researches of recent years.However,the fire-proof property has not been embodied fully in the present standards and criterions.Meanwhile,the tendency of city building getting dense and high-rise make it convenient for citizens,but also bring fire risk at the same time.So it’s in urgent need to carry out the research on the fire-proof property of the exterior thermal insulation system of building external wall.This study mainly investigates the combustion characteristics of the thermal insulation material used in the exterior thermal insulation system and the material composition of fire barrier zone.The experiment results of big scale window fire testing show that the EPS board and XRS board used as the thermal insulation layer can generate empty cavity due to the volume shrinkage when fire occurs,which will act as the channel for fire spread.As the production rate of smoke,CO concentration,and CO2 concentration when one material undergoing combustion process can be used to indirectly reflect the fire hazard of this material,they are all considered as significant indicators to evaluate the combustion characteristics of materials.The orthogonal design table L16(43×26)was adapted in this study according to the analysis of factors and levels.By making 16 different proportion mixtures for the composite fire-proof thermal insulation board,the one with 45% expanded perlite,0.5% fly ash,1.0% anti-crack fiber,5.0% hydrophobic agent,0.5% air entraining agent,20% water glass,5% redispersible latex powder,8% cement,0.3% sodium fluosilicate,and 15% water was tested to be the optimum mixture ratio thermal insulation board.The compound type fireproof insulation board specimen was observed after calcination the shape of the specimen was complete and there was no fracture,collapse,powder and other phenomena.The weight loss rate,shrinkage and strength loss rate of test pieces were analysed before and after calcination that the test pieces pass the fire resistance test.Exterior thermal insulation system of building external wall and fire barrier zone were designed combing with the objectives and requirements,and taking into account the feasibility of practical application.It was for large scale fire test of exterior insulation system.Large scale window fire test which is the focus of this research was designed with fire barrier zone made of different materials in order to enhance fire resistant performance of exterior insulation system.By conducting 4 group big scale window fire testing,It was found that B2 EPS board thin plastering exterior wall external insulation system of large scale window fire test phenomenon and B1 level EPS board thin plastering exterior wall external insulation system of large scale window fire test phenomenon are basically the same.We found that it did not improve significantly to improve the fire rating of the insulation board on the fire performance of the system for thin plastering exterior insulation system.The fireproof isolation belt can act as a barrier for the circulation of the flue gas and effectively inhibit the vertical propagation of the flame in the heat insulating layer.Improving the setting position of the fire isolation belt can further inhibit the propagation of flame in the heat insulation layer;thereby it effectively improves the fire safety of external thermal insulation system of external wall.