Study On Effect Of Fire-protection Structures On Fire Behavior Of External Thermal Insulation-XPS Under Spill Flames

By moving towards the age of Plan in 13th Five-Year, energy security reserve system and building energy efficiency is improving rapidly. External thermal insulation system of buildings is one of the important means to improve building energy efficiency. It has become a requirement to use structure heat insulation measures widely. Especially, the extruded polystyrene (XPS) has become the major threat to human’s life and property. As the exterior wall thermal insulation material, XPS is the main approach from inner building fire to external walls, which determines the important position for the fire behavior research.In this paper, the special shrinkage and melting characteristics of building exterior wall thermal insulation material (XPS) under heat condtion was studied, and the preventing mechanism of fire barrier and horizontal projection on the fire spread process of XPS exterior wall thermal insulation material were also analyzed. The main work include:(1) A series of small-scale experiments were conducted to study the combustion characteristic of XPS, as well as the effect of spill flame on the external wall and external thermal insulation material (XPS). XPS were tested for their combustion characteristic by using self-made adiabat sample holder in Cone Calorimeter. Moreover, the heat release rate were analyzed by comparing with PU, to evaluate fire hazard. A 1:4 reduced size experiment device was arranged to study the relationship of non-dimensional flame height and non-dimensional heat release rate. Reliability analysis was verified by former researchers’data. Under the free boundary, the melting area and the dynamic evolution of XPS over time were discussed under the spill flame varing with heat release rate of fire source.(2) The 1:4 reduced size experiment apparatus was used to focus on the the horizontal projection on the spill flame and the insulation materials of XPS. Based on the new characteristics of the horizontal projection length l1= l1·Dc/l2 and l2’= Dc, a mathematical model of flame height was established combining with horizontal projection width. The effect of horizontal projection to the flame thickness was considered. The probability of fire entrainment was quantitatively analysized, and the relationship with probability of fire entrainment and characteristic length was developed. And then, the inhibitory effect of horizontal projection to the external thermal insulation materials XPS were analysized, as well as the melting area and temperature gradients in vertical direction of XPS.(3) Fire barrier’s effect on the spill flame and XPS was studied in experiments. In the same experiment platform, fire barrieracts as the boundary conditions effecting on exterior thermal insulation material, XPS. From two perspectives of fire barrier height and fire barrier location, differences of characteristic parameters have been cleared. Shrinkage behavior model of XPS is set up under the influence of fire barrier.