Applied Mechanics and Materials Vol. 820

Abstract: The article is focused on the application of the simulation program to calculate the predicted noise levels from a stationary noise source. These findings are particularly important in the case of protected buildings in category II. According to the Health Ministry Decree No. 549/2007 of the Laws. It gives a concrete solution by simulation program CADNA A, for the purposes of noise study.

Abstract: Many manufacturers of spring washers laid under floating floors express the effect of the reduction in a normalized impact noise level as a single digit number ∆L(dB) without defining the composition of the ceiling construction and wear layer, where the reduction in impact noise has occurred. This expression represents the quality and efficiency of washers for general public as well as for experts (architects, designers), which however, cannot be achieved by in situ (on site) measurements.

Abstract: The experience of performed measurements of sound deadening of building structures in constructions sites shows a frequently occurring fact, which is that the walls separating living rooms of separate flats do not meet the required values under the standard. Contractors, designers, but often also the users of flats choose untrusted compositions of auxiliary constructions, whose effect is rather questionable.

Abstract: Experimental measurements have been focused on the issue of change in reverberation time T20 and T30 (s) in a selected room (classroom) due to its occupancy by persons (students) and changes in reverberation time T20 and T30 (s) as a result of the excitation signal during measurement. Reverberation time was measured in a standard room at the Faculty of Civil Engineering of the Slovak Technical University in Bratislava (classroom B318) by the use of NORSONIC (NORSONIC NOR 280 amplifier, an omnidirectional sound source - NORSONIC NOR 270, NORSONIC TYPE 118, and microphone and preamplifier). The room (classroom B318) was selected as a model classroom in terms of its dimensions, i.e. volume (225 m3), arrangement of furniture, and maximum number of students during standard lectures (up to 24 people). The main task of this study was the inter-comparison of measurement results of reverberation times T20 and T30 (s), with regard to room occupancy of students (100%, 50%, 0%), the position of students (sitting and standing), and the excitation signal (pink noise, white noise, impulse - bursting of an inflated balloon).

Abstract: Manufacturers indicate sound insulation of envelope structures of different materials. Acoustical properties of manufactured openings as windows and doors (plastic, wooden, metallic) are known. Following theoretic relations for calculation of consequential sound insulation of acoustic composite wall R_w, it is possible to work out options of walls and openings of various materials.