Operating experience of water tenders was showen that water freezing in tank branch pipes is possible at low temperatures. Therefore it is necessary to provide the demanded temperature conditions for ensuring reliability and operability of fire engines. The analysis of various ways of water protection against freezing in branch pipes revealed that heating of water foam communications by the flexible electric heating elements powered from an in vehicle network of the engine along with the using of thermal insulating materials is optimized. To evaluate the efficiency of such elements we chose a metal reservoir with the diameter close to the delivery pipe from the tank to the pump and placed temperature control thermocouple inside it. The experiment consisted of three stages: without any protection, with the use of thermal insulating material and with the complex protection containing both heating element and thermal insulating material. The reservoir was filled with 16 °C temperature water and then placed outside at temperature -22 °C. The temperature values were controlled by digital multimeter and thermocouple connected to it. The results of measurements showed that without thermal protection water freezing starts in 160 minutes, with thermal insulation it starts in 220 minutes, and with the complex protection - in 477 minutes. Thus, it is possible to apply both ways of protection. The thermal insulation can be constantly used, and heating process can be applied at considerable decreasing of air temperature.