Study On Flame Spread Characteristics Of The Latex Foam

Latex mattress has better permeability and can inhibit the growth of bacteria,which is conducive to promoting sleep.Therefore,it has been favored by people.As a latex mattress filling material,latex foam is foamed by liquid latex.It is extremely easy to burn,once ignited,a large amount of toxic and harmful gases will be released,and a large amount of black smoke and large particles of flocculent float will be emitted,causing adverse social impact.Establishing a scientific fire spread model and timely understanding the development of fire by study the flame spread characteristics can provide useful guidance and references for fire protection design.Flame spread characteristics of solid combustible materials are not only affected by the structure of the material itself,but also by environmental conditions.In this paper,latex foam material was selected as the research object,and a small-size experimental platform was set up by ourselves.With the method of combining experiment and theoretical research,experiments were carried out on latex foam material at different thickness,different ignition positions and different bottom ventilation conditions.In the experiment,the data of flame shape,flame height,sample surface temperature,flame front position,sample quality and so on were obtained,and the change rules of characteristic parameters such as flame height,sample quality and fire spread rate were revealed,and the corresponding heat transfer model was established by combining the theory of combustion and heat transfer.First,latex foams can be classified into thermally thin materials and thermally thick materials according to the relationship between heat penetration depth and thickness.The thermal penetration depth of the samples with a thickness of 1 cm and2 cm is greater than its thickness,which belongs to the thermally thin material;the samples with a thickness of 5 cm belong to the thermally thick material.Thermally thin latex foams have a high rate of fire spread,about twice that of hot thick materials.The combustion time increases with the increase of the sample thickness,the bottom of the thermally thick material ignites later,and the internal temperature of the hot thick material has a gradient change in the vertical direction.Secondly,the study conducted fire spread experiments at different points that have different distances from the center point:0(P1),3.54 cm(P2),7.08 cm(P3),10.62 cm(P4),14.16 cm(P5),and 17.70 cm(P6).The study found that the surface ignition position of the material has a great influence on the fire spread process.The closer the ignition position is to the edge of the material,the shorter the time it takes for the flame to spread to the edge position.In the P2-P6 condition,the closer the ignition position is to the edge of the material,and also,the shorter the burning time.The average fire spread rate first decreases and then increases when the ignition point changes from the center of the material to the edge.The sample mainly transfers heat through heat transfer and heat radiation.As the combustion process intensifies,the proportion of heat radiation increases.Finally,in this paper,the fire spreading process of latex foam under the conditions of bottom unventilated(TF0)and ventilated(barbed mesh aperture sizes which are 1.6 mm(TF1),2.3 mm(TF2),4 mm(TF3),10 mm(TF4),15 mm(TF5))respectively was studied.In the TF0 condition,the bottom of the sample is not ventilated,the burning time is the longest.the larger the size of the bottom ventilation grid is,the more complete the sample burns,the less the residual residue is left.And when the bottom ventilation grid size is larger,the flame spread rate is higher.