This master thesis deals with the assessment of the fire-technical properties of selected thermal insulating materials. The theoretical part of this thesis deals with the current state of the solved problems and the overview of the types of thermal insulation materials, their properties and their use in construction of buildings. The practical part deals with experimental evaluation of thermal insulation materials Natural materials from the STEICO - Protect, Therm, Isorel fiber board have been selected that are environmentally friendly and easily recyclable. The difference between the materials used is mainly in bulk density. The assessment of fire characteristics consisted of an experiment from the ignition test for 15s and 30s according to STN EN ISO 11925-2. The measured data was evaluated in the form of a table. Then was measured data classified according to valid legislation (STN EN 13501-1 + A1). The result was that the evaluated materials fulfilled the classification criteria for the reaction to fire class E.