Experimental study of the influence of heat flux capacity on the ignition and charring characteristics of wood construction materials by using infrared diagnostics

Much heat is released during the propagation of ground and crown fires, which can be a reason of wood construction firing in the settlements located near the forest border. There are a great number of experimental studies on the fire hazard of wooden materials. However, the available data require additional experimental results to study the fire-hazardous characteristics of various construction materials by using infrared diagnostics.
The paper presents the results of experimental study of the impact of heat flux emitted by a standard source on the charring and ignition characteristics of wood construction materials using thermography. The effect of various fire retardants on the charring rate and depth of the samples as well as the ignition time are analyzed. The following widespread wood construction materials are used as studied samples: plywood, chipboard, and oriented strand board.
As a result of experimental studies carried out using thermocouples and infrared camera, a good agreement in the maximum temperature on the surface exposed to the heat effect was obtained. The use of the fire retardant impregnation results in an increase in the ignition time of the sample. At the same time it does not eliminate a possibility of the flame occurrence on the sample surface. The experimental method proposed in this paper allows one to estimate the charring depth and rate of the material exposed to the heat flux effect, and to determine the ignition time.