Investigation on the Emission of Volatile Organic Compounds from Heated Vegetation and Their Potential to Cause an Accelerating Forest Fire

An experimental study is conducted on the emission of volatile organic compounds (VOCs) emitted by Rosmarinus officinalis plants when exposed to an external radiant flux. The thermal radiation heats the plant and causes the emission of VOCs. The thermal radiation simulates the radiant flux received by vegetation in a forest fire. The results of the experiments are used in a simplified analysis to determine if the emissions of VOCs in an actual forest fire situation could produce a flammable gas mixture and potentially lead to the onset of an accelerating forest fire. The experiments consist of placing a plant in a hermetic enclosure and heating it with a radiant panel. The VOCs produced are collected and analyzed with an automatic thermal desorber coupled with a gas chromatograph/mass spectrometer (ATD-GC/MS). The effects of the fire intensity (radiant panel heat flux) and the fire retardant on the VOCs emission are then investigated. Two thresholds of the VOCs emission are observed. The first is for plant temperatures of around 120°C and appears to be caused by the evaporation of the water in the plant, which carries with it a certain amount of VOCs. The second one is around 175°C, which is due to the vaporization of the major parts of VOCs. The application of a fire retardant increases the emission of VOCs due to the presence of the water (80%) in the fire retardant. However, the use of the retardant results in a lower production of VOCs than using water alone. The measurements are used to estimate the concentration of VOCs potentially produced during the propagation of a specific fire and compared to the flammability limits of α-pinene. It is concluded that the quantities of VOCs emitted by Rosmarinus officinalis shrubs under certain fire conditions are capable of creating an accelerating forest fire.

[1]  J. Moreno,et al.  The relationship between terpenes and flammability of leaf litter , 2009 .

[2]  H. Vandendool,et al.  A GENERALIZATION OF THE RETENTION INDEX SYSTEM INCLUDING LINEAR TEMPERATURE PROGRAMMED GAS-LIQUID PARTITION CHROMATOGRAPHY. , 1963, Journal of chromatography.

[3]  J. Peñuelas,et al.  Short-term responses of terpene emission rates to experimental changes of PFD in Pinus halepensis and Quercus ilex in summer field conditions , 1999 .

[4]  Domingos Xavier Viegas,et al.  A Mathematical Model For Forest Fires Blowup , 2004 .

[5]  B. M. Lawrence.  Progress in Essential Oils , 2009 .

[6]  Contribution de méthodes de la chimie analytique à l'amélioration de la qualité de fruits et à la détermination de mécanismes (EGE) et de risques d'incendie , 2006 .

[7]  Darko Stipaničev,et al.  The Kornati Fire Accident – Eruptive Fire in Relatively Low Fuel Load Herbaceous Fuel Condition , 2008 .

[8]  S. Greff,et al.  Monoterpene and sesquiterpene emissions of three Mediterranean species through calcareous and siliceous soils in natural conditions , 2007 .

[9]  J. Peñuelas,et al.  Pinus Halepensis and Quercus Ilex Terpene Emission as Affected by Temperature and Humidity , 1999, Biologia Plantarum.

[10]  Domingos Xavier Viegas,et al.  Parametric study of an eruptive fire behaviour model , 2006 .

[11]  D. Bianchi,et al.  A comparative study of the adsorption and desorption of o-xylene onto bentonite clay and alumina. , 2008, Journal of hazardous materials.

[12]  S. Liodakis,et al.  Testing the retardancy effect of various inorganic chemicals on smoldering combustion of Pinus halepensis needles , 2006 .

[13]  Albert Simeoni,et al.  The Palasca fire, September 2000: Eruption or Flashover? , 2009 .

[14]  John W. Dold,et al.  Fire eruption through intensity and spread rate interaction mediated by flow attachment , 2009 .

[15]  T. Hoffmann,et al.  Diurnal and seasonal variation of monoterpene and sesquiterpene emissions from Scots pine ( Pinus sylvestris L.) , 2006 .

[16]  Tarik Chafik,et al.  Physicochemical characterization and adsorptive properties of some Moroccan clay minerals extruded as lab-scale monoliths , 2007 .

[17]  D. X. Viegas,et al.  Safety and awareness of people involved in forest fires suppression. , 2002 .

[18]  Laurent Catoire,et al.  Estimation of temperature‐dependent lower flammability limit of pure organic compounds in air at atmospheric pressure , 2005 .

[19]  V. Baldy,et al.  Production and Diversity of Volatile Terpenes from Plants on Calcareous and Siliceous Soils: Effect of Soil Nutrients , 2008, Journal of Chemical Ecology.

[20]  C. N. Hewitt,et al.  Screening of 18 Mediterranean plant species for volatile organic compound emissions , 1997 .

[21]  D. Drysdale.  An Introduction to Fire Dynamics , 2011 .

[22]  Patricia L. Andrews,et al.  Fire behavior associated with the 1994 South Canyon fire on Storm King Mountain, Colorado , 1998 .