The diploma thesis deals with the computational determination of the lower explosive limit of paints. The lower explosive limit represents the lowest concentration of a flammable substance in a mixture with an oxidizing agent, which is explosive after initiation, is a key property of flammable substances from the point of view of explosion protection. For the computational determination of the lower explosive limit, we chose three flammable liquids, which are represented in the woodworking operation in the largest amount: varnish TU 7425/00, hardener TH 0790/00 and solvent DT 1200/00. We determined the lower explosive limit using Le Chatelier's rule and compared the results with the safety data sheets of individual flammable liquids. We calculated the concentrations of flammable vapors for three model situations in the production plant (in the paint shop, in the warehouse and in case of fire). Concentrations of vapors of flammable liquids were in the range of explosiveness, solvent 4.03 vol.% and 7.8 vol.%, varnish 2 vol.% and 3.9 vol.%, where there is a risk of explosion and therefore measures must be taken to reduce the occurrence of an explosive atmosphere in operation. The concentration values of the hardener vapor are higher than the upper explosive limit, namely 12.9 vol.% and 24.8 vol.% however, we do not consider the concentration to be safe. Selected flammable liquids present an increased risk of explosive atmospheres due to low values of the lower explosive limit, namely the solvent represents 1 vol.%, hardener 1.9 vol.% and varnish 1 vol.%. For this reason, it is necessary to take organizational and technical measures into operation.