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The paper aims to propose ways for enhancing the effect of attenuating shock waves in the water mist. The fulfillment of this task can significantly contribute to the perfection of technologies for protecting from accidental explosions and the design of protective facilities. A series of experiments were carried out to investigate the influence of air gaps on shock wave attenuation in the water mist. A shock tube with hydraulic equipment capable of producing a 3-meter long dispersed water barrier with droplets ranging from 25 to 400 microns and total flow rate 14.5 l/s within a tube was used during testing. The paper analyzes shock wave attenuation within a tube in the water mist with and without air gaps. It has been established that in conditions when a 3-meter long water mist contains four air gaps, every 20 centimeters in width, overpressure reduction coefficient is 1.10-1.15 times higher than the one in the water mist without air gaps.

Existing problems of security is strongly connected to terrorist and accident explosions and fires. Physical protection of critical infrastructure requires the creation of reliable system providing quick and accurate identification of the hazards and subsequent transmission of the alarm signal to the protection device. The paper describes the basic requirements and structure of the wireless device for the detection of explosions. Proposed wireless device consists of transmitter and receiver modules. A transmitter module contains the sensors and a microprocessor equipped with a blast identification software. A receiver module produces an activation signal for the operation of protection devices. The paper presents the test results of the proposed wireless device, carried out in the underground experimental base of the G. Tsulukidze Mining Institute.

Mist generator is a basic element of systems designed to protect from explosions. It is responsible for forming a suppression barrier between the place of explosion and the zone to be protected. The effectiveness of the system is determined by the capacity of the mist to suppress blast overpressure and impulse. The attenuation capacity, on its turn, depends on mist properties, such as droplet size, water concentration in mist and droplet velocity. The paper examines droplet velocity influence on overpressure and impulse attenuation in mist when the properties of the latter are in the following ranges: droplet size - 15-345 μm; droplet velocity - 5.5-35 m/s; shock wave velocity – 515-718 m/s, droplet impact angle - 900. The influence of drop velocity on blast attenuation has been assessed according to overpressure and impulse reduction factors.