MONITORING OF LOW-FREQUENCY SOUND AND INFRASON LOAD ON THE PRODUCTION ENVIRONMENT AND MEANS OF REDUCING IT

Abstract

The monitoring of low-frequency sound and infrasound in the city in octave frequency bands was carried out. It is shown that the levels of this factor exceed the maximum allowable values in road and urban electric transport. Non-normative values of infrasound are observed near the railway line. An analysis of possible approaches to reducing the levels of low-frequency sound and infrasound at least inside buildings. The advantages and disadvantages of resonant and membrane panels for the absorption of lowfrequency elastic waves are shown. The calculation apparatus for determining the absorbing properties of structures is given. It is proved that for effective protection the structure must be tuned to the minimum peak frequencies, which ensures the absorption of waves of higher multiples of frequencies. A two-layer design tuned to the two most critical sound and infrasound frequencies is proposed. Additional filling of the gap between them and the gap between the structure and the mounting surface (wall, ceiling) with standard soundabsorbing material allows to increase the overall noise protection. The calculation of the perforated noise protection panel, which is used in the case of one significant peak in the low-frequency or infrasonic region, is given. Such a panel is effective from 100 to 150 Hz. The possibility of simultaneous reduction of electromagnetic field levels is proposed. This is achieved by adding a metal-containing substance to the intermediate sound-absorbing material. This can be ensured by the use of fine iron ore concentrate, which is well implanted in any material and has a low cost. The possibility of coating rigid elements of the soundproof structure with a special paint for shielding electromagnetic fields of a wide frequency range is shown. This will protect people from the two most critical man-made physical factors.