The effect of (NH4)2HPO4 and (NH4)2SO4 on the spontaneous ignition properties of Pinus halepensis pine needles

Abstract The spontaneous ignitability of Pinus halepensis pine needles was evaluated. Fire points and times taken for irradiated fuels to be ignited were correlated, at given heat intensity, to the airflow around the specimen and the sample size. The tests showed that increase of the airflow rate above 1.5 l min−1 increased considerably the fire point values and ignition delay times. On the contrary, the sample size in the range investigated (0.2–1.0 g) showed a negligible effect on the ignition properties. The influence of fire chemical retardants (NH4)2HPO4 (DAP) and (NH4)2SO4 (AS) on the ignitability characteristics was studied under various concentration levels. The data in this study showed that the presence of DAP and AS increases the fire point, as well as the time required for ignition, and this effect is pronounced at high concentration levels. However, at lower temperatures, i.e. below 500°C, flaming combustion appears sensitive to the AS quantity applied, whereas at high temperatures (i.e. above 600°C) the DAP concentration had a major influence on its flammability behavior. In addition the time of combustion was slightly extended, therefore, the energy release rate was reduced in the presence of fire retardants, particularly of AS. The purpose of this study was to quantify the fire extinguishing capabilities of (NH4)2HPO4 and (NH4)2SO4, commonly used chemicals in forest fires, by comparing the ignition properties of samples, prior and after retardant loading.

[1]  Tomás Cordero,et al.  On the kinetics of thermal decomposition of wood and wood components , 1990 .

[2]  John W. Lyons,et al.  The chemistry and uses of fire retardants , 1970 .

[3]  H. Horacek,et al.  Advantages of flame retardants based on nitrogen compounds , 1996 .

[4]  Marc Janssens,et al.  Piloted ignition of wood: A review , 1991 .

[5]  A. Pappa,et al.  The effect of salt and oxide-hydroxide additives on the pyrolysis of cellulose and Pinus halepensis pine needles , 1996 .

[6]  R. Susott,et al.  Chemical composition of forest fuels affecting their thermal behavior , 1986 .

[7]  Patricia L. Andrews,et al.  Introduction To Wildland Fire , 1984 .

[8]  R. Susott.  Differential Scanning Calorimetry of Forest Fuels , 1982 .

[9]  Gert B. Eijkel,et al.  Curie-point pyrolysis-capillary gas chromatography-high-resolution mass spectrometry of microcrystalline cellulose , 1989 .

[10]  W. E. Muir,et al.  Pilot ignition of building materials by radiation , 1968 .

[11]  Walter J. Murphy,et al.  ADVANCES IN CHEMISTRY SERIES: Numbers 15 and 17 Demonstrate Rapidly Crowing Interest in Documentation; International Conference To Be Held in 1958 , 1956 .

[12]  G. F. Levchik,et al.  Mechanistic study of combustion performance and thermal decomposition behaviour of nylon 6 with added halogen-free fire retardants , 1996 .

[13]  M. Statheropoulos,et al.  A comparative study of the effects of fire retardants on the pyrolysis of cellulose and Pinus halepensis pine-needles , 1995 .

[14]  Roger M. Rowell,et al.  The Chemistry of solid wood , 1984 .

[15]  A. Pappa,et al.  The effect of (NH4)2HPO4 and (NH4)2SO4 on the composition of volatile organic pyrolysis products of cellulose: PY-GC studies , 1997 .

[16]  D. L. Simms.  Experiments on the ignition on celluslosic materials by thermal radiation , 1961 .

[17]  Gert B. Eijkel,et al.  Pyrolysis high-resolution gas chromatography-mass spectrometry studies on beech wood: capillary high-resolution mass spectrometry of a beech lignin fraction , 1987 .

[18]  M. Statheropoulos,et al.  Thermal analysis of Pinus halepensis pine-needles and their main components in the presence of (NH4)2HPO4 and (NH4)2SO4 , 1995 .