Dušan Dlhý

The Effect of Free Joints on Sound Insulation of Constructions

Noise protection of a building ́s interior is one of the fundamental functions of building constructions. These constructions can be understood as internal partitions, ceilings or external wall-/roof claddings. However, walls often consist of basic building materials and openings; such windows and doors as well as the acoustical properties of such structures are determined by both parts (e.g., a windows and the wall structure). The acoustical quality of opening is in general affected not only by the particular structure, but also by the concept of the mounting. Acoustical requirements should be applied in all its parts, such as the construction of the window (door) frame, window (door) wing and the realization of the functional gap as well as by application of a sealant. On the base of experimental measurements in Acoustics Chambers of the Faculty of Civil Engineering of Slovak Technical University and mathematical analysis we have determined index of sound insulation of free joint.

The Effect of a Front Frame on the Increase in Sound Insulation of an Acoustically Simple Wall - Results of On-Site Measurements

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.

The Use of Simulation Tools in the Assessment of External Stationary Sources in Terms of Noise

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.

The Results of Experimental Measurements of the Effects of Floating Floor Washers

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.

Effects of the Sound Insulation of the Outer Structure on the Price

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 Rw, it is possible to work out options of walls and openings of various materials.

Experimental Measurements of Effects of Occupancy Class on Reverberation Time

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).

The Dispersion of Acoustic Energy in the Dissemination from the Source

Methodology of the way of supposed sound levels calculations in closed objects areas from the sound sources is based on assumptions, that the propagation of sound is dominant. In many cases the acoustic properties of space of sound propagation have great importance. We have to take in the consideration - the size and cross-section areas of dispersion bodies, their sound absorption coefficient; - shape of area and boundary areas absorption; - position of concerning point in relation to the source position in space; - noise of technological equipment and relatively other coefficients that may effect the sound energy propagation.

Influence of Double Transparent Facades on Acoustic Comfort at the Workplace

Comfort in the workplace is a priority for employers to achieve higher efficiency of their employees. The issue of an ideal environment in buildings and improving psycho factors are increasingly current topic. In areas with high noise level (LAeq) in exterior, it is difficult to achieve the acceptable noise level (LAEX,8h) defined in the Regulation of the Government 115/2006, while maintaining the possibility of opening windows in the office. Double transparent facade (DTF) is one of the alternatives to achieve the effect. This paper presents an initial analysis of acoustic measurements DTF focused on the insulation, conducted at the central building of the Ingsteel company in Tomášikova street in Bratislava. The paper is supported by the project VEGA č.1/0358/13.

The Influence of the Shape Space on the Scattering of the Sound Energy

The sound level adjacent to the sound sources is mainly characterized by the straight sound. The dispersion sound ratio is increasing with distance increasing and within the limited range round the sound source, the sound level is higher, in the area with dispersion bodies even higher than in an empty area. The laws of sound propagation in empty areas are derived on classical geometric base. The laws of sound propagation in large areas with dispersion objects are also derived from these laws complemented with the Kuttruff ́s equation of reverberation process in media with dispersion bodies. Simultaneously the sound energy is according to the purpose divided into the straight sound and the reverberation. The straight sound is the energetic ratio of sound, that is during the way to destination not dispersed and the propagation laws are equal to empty areas propagation laws are equal to empty areas propagation laws. The dispersed sound is the ratio of sound energy that reaches the destination after one or more reflections. The energy result is then the sum of densities of dispersion and straight sound.

Selected Problems of Renovated Apartment Buildings Entrances in Slovakia

During the last decades, only a little attention has been given to the design and renovation of the entrances to residential buildings. Given underestimation of the problem in the design has resulted in a negative impact on both indoor building environment and aesthetics of the building. Recently, together with the renovation of external walls claddings (by application of additional thermal insulation and replacements of windows and doors) and upgrading and modernizing the installations services such as heating and plumbing systems, also the entrance construction components finds their place in the renovation process. This article analyses the problems connected with renovation of building entrances and summarizes information about the current efforts in engineering and architectural praxis.