Acoustic Calculation of the Notification System for the Alarm System

Abstract

Firstly, the design of emergency alert systems consists in calculating the number of audio or speech emitters that is necessary to ensure sufficient sensitivity and readability of the message. Calculations are based on the power of the emitter and the value of the sound level pressure that must be created depending on the destination of the room. Secondly, you should choose the optimal layout of the detectors for the specified dimensions of the room and its configuration. For the convenience of performing calculations by leading companies – manufacturers of relevant products have developed a variety of software options, so–called acoustic calculators. In Ukraine, the design of emergency notification systems is not given enough attention. This leads to the fact that designers use information to install predominantly Russian information resources. Developers of Russian companies have certain disadvantages, as well as executed in regulatory documents that are different from the international standards adopted in Ukraine. The article proposes a method for creating software for calculating the notification system. The calculation is based on the distance definiteness from the detector to the sounding plane, which satisfies the condition of maintaining a given level of sound pressure. Calculations are performed separately for sound (non–directional) detectors and speech emitters. In this work, the approximated directional characteristics of detectors, which were considered in horizontal and vertical planes, were used. The directed action of speech detectors is taken into account by the value of the directional factor at the frequency corresponding to the maximum radiation energy. The result of the is the number of selected detectors, the type of their placement system (which is selected by the user, but can be adjusted during the calculation, as well as the detector type), the scheme of their placement in the room. The article provides an interface program and examples of calculations with a sample of calculations for two rooms. For selected premises, the results obtained using the acoustic calculator are checked by calculating the sound field by the analytical method as well as by the experimental one. In the premises, recommended notification systems are installed, and measurements of sound field levels are performed. Analytical calculations and experimental data confirm the reliability of the results obtained with the help of the developed acoustic calculator. Ref. 14, fig. 7, tabl. 2.