Insulation Properties of Boards Made from Long Hemp (Cannabis sativa L.) Fibers

Long fibers from fast growing hemp (Cannabis sativa L.) were used as a raw material for the production of insulation boards in this preliminary work. Hemp fiber boards with densities that ranged from 300 kg/m(3) to 1100 kg/m(3) were studied. The boards were pressed as one- or three-layered structures. In the three-layered structure, the core was formed of hemp fibers and the outer layers were manufactured from 1,5-mm thick birch veneers. The basic insulation properties of the boards were tested. The heat transfer coefficient value for the boards without veneers allowed this material to be classified as an insulating material. Although the additional veneer layers significantly impaired the heat transfer coefficient, its value was still lower than that of standard wood-based board materials with a similar density. The produced boards were characterized as having good noise reduction properties. The acoustic insulation factor was higher compared with boards intended to be used as thermal insulation, such as mineral wool or light fiberboards with four times greater thicknesses.