In work, the technical possibilities of using personal respiratory protective equipment are considered as an object of research. Such funds are used in fire and rescue units, during emergency rescue operations related to the liquidation of emergency situations with the release of hazardous chemicals. It is shown that one of the most problematic places for the participation of personnel of fire-rescue units is the contradiction between the protective properties of personal protective equipment and the danger that may be in the organization of the release of a hazardous substance. This applies to the personnel of firefighting and rescue units, which are the first to start carrying out appropriate rescue operations. As a result, even with the full implementation of existing regulatory requirements, work in isolating devices can be dangerous for the rescuer. At the heart of the chosen approach to the solution of the task in view lay the assessment of the possibility to provide such a general protection factor of the insulating device in the assembly with the front part, which will exceed the coefficient of toxic environmental hazard. The study used an analytical definition of the requirements for the testing of compressed air equipment equipped with helmet-masks. It showed that rescuers can work at the epicenter of an accident with the release of hazardous chemicals, if in checking the tightness with the help of devices when creating a test vacuum of 2000 Pa, the rate of the decrease in vacuum will not exceed 32 Pa/min. However, experimental verification of the obtained theoretical results allows to state that the fire and rescue unit will not be able to achieve this requirement. Increasing the test dilution to a level that exceeds 1000 Pa is accompanied by a significant increase in the suction in the system «insulating apparatus – respiratory organs». It has been proven by experience that protection devices are provided with compressed air, equipped with pulmonary automatic devices, which create an overpressure air in the UMS. In this case, the threaded connection of the insulating device with the front part must not be used. This allows to recommend the use of compressed air devices equipped with pulmonary automatic devices as a basic set of isolating apparatuses, creating air overpressure in the UMS Exceptions are subdivisions, in the area of operational departure of which there are facilities on which there is a large number of hazardous chemicals with a toxic hazard coefficient of more than 2,3·10 5 . In this case, they should be completed with complexes of personal protective equipment of ampoule type.