Extinguishing fires in low temperature conditions presents special challenges in view of the fact that there are breakages of mobile fire extinguishing means, reduction of supply of fire extinguishing substances, owing to frosting of hose lines and fittings. Development of the fire to the large sizes in the conditions of low temperatures will depend in many respects on level of training of staff, the equipment technology, and also on extent of influence of climatic factors on mobile means of suppression of the fires. There is a situation when water supply decreases by fire extinguishing over time, and because of influence of a climatic factor it isn’t possible to use the tactical capacity of divisions of rescue and fire fighting garrison. The results of a research directed to definition of intensity of frosting of hose lines and hose fittings depending on various factors are presented in this article. Methods. Measuring complexes which allowed to take water temperature in each point of pumping and hose system of the fire truck developed by the staff of State Fire Academy of Emercom of Russia were used for conducting pilot study. Results. As a result of the conducted researches it was established that possibility of chilling of water in the hose line and fittings depends on temperature of air, speed of wind, diameter and material of a fire hose, a water consumption in the hose line. On the basis of the received results of researches the mathematical model for assessment of parameters of work of hose lines in the frosting mode is offered. Research application field. The received results allow to estimate previously possibilities of firefighters of divisions in case of suppression of the fires in the conditions of low temperatures. Conclusion. As a result of the conducted researches the technique of assessment of operability of the pressure head hose lines functioning in the conditions of low temperatures is formulated.