Thermal treatment for bed bugs.

It is the challenge of every thermal treatment to achieve the lethal temperatures in inaccessible harborages. With thermal treatments hot air is the heat transfer medium. This medium has a low heat capacity and the heat transmission rate from hot air on a solid body is relatively poor, especially if there is a small temperature difference between the heat transfer medium and the surface of the body. It is necessary to move big volumes of hot air with a turbulent flow. The resulting rise in temperature is not more than 5°C per hour and this slow rise prevents damage of the surrounding materials. The operating band to kill bed bugs without damaging materials is 15-20°C and lies between 45°C and ~60°C. Holding a constant high temperature after heating up is necessary to penetrate cracks, crevices and hollow spaces. A permanent temperature control at many measuring points with a hand-infrared measuring device followed by corrections through newly positioning the heater/ventilator are necessary. Not all cold spots were detected before the treatment and that the thermocouples were not always placed at the critical points. The movement of bed bugs to cooler areas begins above temperatures of 30-35°C. This escape is interrupted through applying physical and /or chemical barriers.