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We investigated the effects of a floating floor on heavy impact sound in the low-frequency range below 100 Hz with focus on the structural vibration. To verify the mechanism of amplifying the floor impact sound, field measurements were conducted before and after the installation of a floating floor while the other conditions were kept constant. Field tests were performed on five apartment units where the material properties of the resilient materials in the floating floors differed. Slab accelerations and sound pressure levels were measured simultaneously. The test results indicated that the low-frequency responses of slab acceleration and the corresponding heavy impact sounds were amplified in all apartment units after the installation of the floating floor, while high-frequency responses greater than 100 Hz were significantly reduced. The amplified responses were attributed to the interactions between the mortar plate (floating floor) and concrete slab, which were connected by a resilient material layer. The degree of amplification tended to increase as the loss factor of the resilient material decreased while the amplified frequency range was determined by the stiffness of the resilient material layer. The result was numerically verified using a simplified mass-spring model.

Structure-borne noise and vibration from weight drops and fitness activities are an ever-increasing source of disturbance within multi-residential, hospitality, and multi-tenant commercial buildings. High-mass floating floors supported on low-resonant frequency isolators have been used with good effect to reduce impact noise and vibration, but commonly require expensive supplemental supports or structural stiffening to be implemented properly. Common light-touch fitness solutions feature continuous or interlocking resilient surface treatment. This approach is often ineffectual at high-energy impact fitness areas and the pursuit of soft surface solutions to achieve greater dissipation of impact energy can create an unstable surface for weightlifting. An alternate approach to reducing structure-borne noise exists which focuses on dissipating the impact energy through constrained layer damping in conjunction with low-resonant frequency isolators. Research and development testing shows that an engineered all-dry lightweight fitness floating floor is capable of achieving equal or greater impact insulation performance than a high-mass concrete floating floor and significantly better performance than light-touch resilient surface treatment. A review of the testing and development process and underlying principles will be reviewed to illuminate the mechanisms at work in the next generation of fitness floating floors.

In the present study, the vibration characteristics of floating floor systems and the discomfort in walking upon them have been studied in concrete slab structures through mock-up floors experiments. Seven types of floor systems, with panels of various sizes and supporting beams with different joist spacings, were constructed based on actual conditions. For the vibration measurement, an ISO rubber ball dropped from a height of 20 cm was used as an impact source to reproduce human walking. The vibration characteristics were evaluated by calculating the vibration acceleration values and the autocorrelation function parameters for the floor structures. Finally, a human walking experiment was conducted to investigate subjective responses to the vibration characteristics of floating floors. From the results, it was found that the vibration acceleration values and walking discomfort varied with the supporting conditions of the floors and that these were highly correlated with each other. It was also found that more than 75% of subjects accepted the floors when the vibration value of the floor in terms of vibration does value (VDV) is below 4.8 ms(-1.75). In addition, a practical regression of the VDV was obtained and design guidelines for floating floors were suggested.

Crossfit facilities in dense, multi-use facilities are growing in numbers every day. Even minimally sensitive receivers can be very significantly impacted by Crossfit activities. Consequently, vibration and vibration induced noise in structures as a result of heavy weight drops are a never ending issue. This paper compares data recorded from heavy weight drops in an ASTM E492 floor/ceiling testing suite. The resultant sound pressure level in the receiving room and vibration levels in the structure are measured. Several different standard and high performance resilient sports floorings are compared. These sports floors are tested on single concrete slabs as well as various floating slabs. The floating slabs include continuous rubber underlayments, discrete rubber isolators and spring jack-up floating floors. In addition, laboratory impact and airborne isolation performance results of a spring jack-up floating floor are reported.

Creep-induced changes in dynamic stiffness of resilient interlayer used for floating floor is an important parameter of vibration isolator in long-term use. Compressive creep behavior of a composite layer made from closed-cell foam and fibrous material is investigated using a Findley equation-based method recommended by International Organization for Standardization (ISO). Quasi-static mechanical analysis is used to evaluate the dynamic stiffness influenced by the creep-deformation of the composite layer. It is shown in the present work that the long-term creep strain of the interlayer under nominal load of the floor and furniture is within the zone where dynamic stiffness increases. The changes in low frequency impact sound by the long-term creep deformation are estimated through real scale laboratory experiments and numerical vibro-acoustic analysis.

CrossFit training is a popular fitness training method. Some facilities install lightweight plywood floating floor systems as a quick, inexpensive method to mitigate impact generated noise and vibration into adjoining spaces. Part of the CrossFit training regimen involves lifting significant weight overhead, and then dropping the weight on the floor. The energy transferred to the floor system can cause severe damage to floor surfaces and structures; and, when using a lightweight floating floor system, even the isolators can be damaged. This paper describes a spreadsheet based analytical model being used to study the effects of such impacts on various floor systems. This study is a prelude to experiments that will be performed on a full scale model test floor. The results of those experiments will be used to verify the model so that it can be used as a design tool for recommending solutions for mitigating the noise and vibration in adjoining spaces due to floor impact problems. Also discussed in this paper are the qualitative results of some preliminary tests performed in order to better understand the mechanics of impacts on floating floor assemblies.

The effect of materials with supporting conditions on the vibration characteristics of the floating floor systems have been studied in concrete slab structures. Total 10 types of floor systems which have various sizes of panels and supporting beams with different joints were made based on actual conditions. In the measurement of vibration, ISO rubber ball was used as an impact source in order to reproduce human walking. The vibration characteristics were evaluated through calculating the vibration dose value (VDV) and autocorrelation function (ACF) parameters for the vibrations of the floor surface layers. Finally, a human walking experiment was conducted to investigate the subjective responses to the effect of vibration characteristics of the floating floors. As results, the correlation coefficients between physical parameters and subjective responses were derived and a perception model was obtained.

The Act on the Promotion Wood for Public building was enforced in October, 2010 in Japan. According to this act, a public building in a low layer assumes a wooden construction as a rule or positively uses wood. Moreover, it is expected that the building such as apartment houses comes to be made from wooden. However, the floor impact sound insulation performance of the wooden constructions is low compared with that of the concrete constructions. This paper presents the effect of floating floor (dry double system floor) and raised floor (free access floor) on floor impact sound insulation performance in wooden construction. A reference floor constructed with the wood-frame construction was installed in the floor opening of the reverberation chamber, and the floating floors or the raised floor were built on it. Then, the reductions of transmitted floor impact sound level of them were measured. The results showed that the density of the surface material influences the floor impact sound interception performance in the case of the floating floor. In addition, the reductions of transmitted floor impact sound level in wooden construction were compared with them in concrete construction in the case of the raised floor.

New product information with a focus on performance, practice, and rehearsal room acoustics will be presented. Performance-area acoustics are enhanced by full-stage acoustical shells, ceiling panels, and clouds for the audience area. These range from standard products to unique customizations. Portable shells that roll through standard doorways will also be shown. New modular sound-isolating practice rooms feature enhanced acoustic performance, improved aesthetic appearance, and upgraded optional floating floor. Active acoustics technology can be retrofit in an existing room, such as a teaching studio. Interesting applications of acoustical doors will also be highlighted. Other products include instrument storage cabinets with tunable absorption integrated into the design. An acoustic shield positioned behind an individual performer helps reduce potentially damaging sound energy from behind, as indicated by binaural measurements and recordings. Finally, an acoustician-specific, restricted-access website f...

A method will be described to estimate the transmission loss (TL) of a floating floor separated by an elastomer from a structural concrete floor, using the prognosis method. The system resonance is determined by the two masses and the combined stiffness of the elastomer and the constrained air. At low frequencies, the TL curve has a slope of 6 dB/octave based on the mass of the double system. At the resonant frequency (fr) of the system, the TL is strongly reduced. Above fr, the isolation increases rapidly at a rate of 18 dB/octave until the upper limit of 12 dB/octave is reached, due to the sum of the isolation of the two masses. Several examples of different floating floor options, using MS Excel software program, will be provided to illustrate the effects of the floor masses, the fr of the isolator, the stiffness of the constrained air layer, and flanking.

Earlier studies for the improvement on airborne and impact noise insulation of ceilings in prefabricated standard house‐buildings has been continued by the support of the German Ministery of Building. The investigated slab blocks were erected in 1987 in Potsdam. The raw ceilings made of solid concrete have a thickness of 140 mm. These realized ceilings have a weighted airborne sound insulation of Rw′=49 dB and a normalized impact‐sound pressure level of Ln,w′=77 dB (averaged over nine measurements). A selection of floating floor materials were built in and measured: dry laser constructions (with plaster and compound cement slabs), asphalt applied by melting, and anhydrite layers. The aim of the project was to fulfill the requirements (Rw′=54 dB, Ln,w′=53 dB) of German Standard DIN 4109 from 1989, minimizing construction height and cost. Based on earlier studies (Scholze, DAGA ’94) all floating floors with a height larger than 45 mm (asphalt floor 40 mm) have been improved to reach the requirements of DIN ...

The French thermal regulation (RT2005) is favoring thermal floating floor between spaces such as parking or stores, and dwelling units. However, these solutions do not fulfill the French acoustic regulation with regards to airborne noise. This paper discusses the development of solutions allowing fulfilling both the thermal and the acoustic regulation. To achieve this goal, a mixed approach combining measurements and numerical predictions is used. Furthermore, the laboratory characterization of such floating systems usually involves a concrete base floor 140 mm in thickness (following the NF EN 140‐8 standard) and a floating concrete layer 40 mm in thickness. However, in situ the concrete base floor as well as the floating concrete layer can be thicker. Therefore, some laboratory measurements are performed on a thermal floating floor system combining a 200 mm thick concrete base floor, a thermal insulation layer (polystyrene or polyurethane based foam for example) and a 60 mm thick floating concrete layer. The prediction method shows that this type of thermal floating systems is not acceptable with respect to the acoustic regulation. The behaviour of such multilayered systems is investigated using a wave approach based prediction tool in order to develop solutions allowing fulfilling the acoustic regulation.

The new Belgian requirements demand DnT,w⩾58 dB and L'nT,w⩽50 dB between apartments for enhanced acoustic comfort. At the same time the Energy Performance Regulations impose strict requirements for the thermal insulation between apartments. Higher demands on sound insulation can be realized in practice by using higher surface weights for walls and floors and by applying failure free floating floors. However requiring higher weights for floors is in contradiction with the technique of concrete hollow floor elements. A thermal and acoustical solution was found in the development of dB‐deck, a prefab double floor element with intermediate supporting elastic pads, cutting structural vibration paths between superposed apartments. In combination with double walls without anchors (allowing for a high sound reduction index and no structural transmission in the horizontal sense), this construction technique allowed for DnT,w>63 dB and L'nT,w

The floating floor with multilayers of resilient materials was investigated for the isolation of floor impact sound. The floor structures were evaluated in the reduction of the heavy‐weight impact sound, which is mainly affected by the boundary conditions of the tested floors. The values of single‐number ratings for floor impact sounds decrease dramatically for floated floors. Insertion loss is determined by the vibration characteristics of a bare slab, such as transmissibility. The logarithmic decrement (ξ) of the vibration responses was 4 times higher than that of the bare slab. Above 125 Hz, the vibration between the slab structure and floating floor is isolated effectively. It was revealed that the resonant frequency of the slab structure and the damping factor of the floating floor are important aspects for impact sound isolation.

The most common floor constructions in Italian buildings are composed of two parts: the structural one, made of concrete beams and perforated bricks, and the floating floor. The results of the in situ measurements of the impact sound pressure level, realized on the structural part of the floors, show a frequency spectrum trend that increases with the frequency. The spectrum is also characterized by many peaks and dips at the high frequency range that strongly influence the determination of the weighted normalized impact sound pressure level, also for structures with similar mass and geometry. The frequency trend of the beam and brick structures is completely different from the characteristic spectrum of homogeneous concrete slabs or lightweight structures. Considerations on how those differences can influence the obtainable results in terms of the reduction of impact sound pressure level referred to the same floating floor typology, the spectrum adaptation terms and the other acoustic quantities described...

We reconstructed a studio that has a space in which to record effect sounds. In this space, we record walking sounds on wooden floors, tile floors, sand, grass, and so on. This studio was planned on a floor with a light allowable load because the floor was formerly the roof of the building. A recording studio is usually constructed with a floating structure. The thin floating floor causes vibration of floorboards. A thick floor is heavy. In addition, we recorded the sound when we jumped on the floor. The noise from the structure disturbs the effect sounds that we need if the vibration caused by jumping stimulates the studio structure. For those reasons, we planned the following design to record pure effect sounds: The effect sound space is insulated from other spaces with the room structure. A floating ceiling is hung from the fixed ceiling, and parts of floating walls are hung from overhead beams. Only the floating floor and the other parts of floating walls are set upon the fixed floor. Consequently, the floating floor in the effect sound space was made thicker than would be possible otherwise.

Floating lining systems have been adopted to reduce the noise level in cabins, and the reduction level has been about 10 dB(A) as compared with no floating lining system. The authors pointed out the reason the conventional floating lining systems have poor effects and proposed a concept for a new floating lining system, which consists of a box made of four lining walls and a ceiling set on a floating floor, and the box has as few connecting points with steel structures as possible. In order to promote the system for practical use, experiments were carried out by using a two‐third scale model of a cabin. The first experiment with the lining set on a floating floor was carried out without a connecting point to the steel structures, and, in the second step, a rubber piece connected the lining ceiling with the steel structures to prevent lining deformation by the motion of a ship. The second experiment was done to investigate the influence of a connecting point on the vibration level of the lining. As a result, the proposed system could be expected to reduce the vibration level by about 20 dB in the high‐frequency range as compared with the conventional floating lining systems.

Theater design for cruise ships presents many challenges that are different than building designs on land. The acoustic challenges include a limited palette of material choices based on weight, space, and fire restrictions, room adjacency issues, and coordination with shipyard construction methods. We will discuss the program uses of the spaces and the acoustic criteria, architectural treatments, room shaping and volume, sound isolation utilizing sandwich and floating floor constructions, and HVAC noise control without the use of fiberglass. We will specifically focus on the design for Royal Caribbean Cruise Lines Voyager, Millennium, and Radiance class ships. Information will be presented that could be transferable to land based designs to solve acoustic problems that involve similar weight, space, and fire restrictions.

This study aims to examine some kinds of plans to solve the ploblem of noise and vibration transmitted to adjacent rooms, especially to the downstairs, when using SMT (surface mount technology) equipment. To achive this, a kind of system for preventing noise and vibration was applied, and the effects of sound insulation performance for that were tested and analyzed. To reduce floor impact noise, a floating floor system using a plastic pallet and rubber was applied. The applied plastic pallet is 30 cm wide, 60 cm deep, and 6 cm high and designed to array on a concrete slab. Above this plastic pallet, a 14‐cm‐thick concrete slab was constructed. After installation of this system the floor impact sound was reduced about 7 dB(A). For more reduction, a ceiling with a 5‐cm‐thick glass wool and twofold of 0.9‐cm‐thick plywood was constructed at the directly below downstairs. According to this, 4 dB(A) was additionally reduced.

The Yokohama Minato Mirai Hall was planned as a complex cultural facility on the waterfront of Yokohama City and was opened in June 1998. In this building, a large concert hall with 2020 seats (mainly for symphony concerts) and a small concert hall with 400 seats mainly for chamber music are included. For the design and construction of this building, an acoustic design and research group consisting of architects, acousticians, and building engineers was set up and such various acoustic problems as room acoustics, sound insulation between rooms and facades, prevention of structure‐borne sound from subway by floating floor construction, and noise reduction of the air‐conditioning system were investigated by cooperative work in the group. For the acoustic design of the two halls, computer simulation based on geometrical acoustics and a 1/10 scale model experiment were performed for checking room shape and auralization studies. During and after the construction, acoustic measurements were carried out under various conditions. Before the opening, test concerts were performed with an audience, and acoustic data under occupied conditions were obtained. In this paper, the outline of the design process and the acoustic characteristics of the two halls are introduced.

Modifications were required to reduce sound levels in a former office so that the room would meet the ambient noise requirements for audiometric testing. Sound sources in the area included people in neighboring offices, transformers in a neighboring mechanical equipment room, ventilation ducts in the plenum above the room, and air‐conditioning vents. The transformers created harmonically related vibration tones in the concrete floor slab and walls that radiated sound into the proposed audiometric test room. Acoustical recommendations consisted primarily of building a vibration‐isolated room within the existing room (including a floating floor) and acoustically treating the ventilation system. Initial measurements revealed unexpectedly high sound levels that were the result of unintended (erroneous) structural connections between the inner and outer room. When these connections were cut, the room met the noise requirements.

A free floating hard wood floor system has upper and lower subfloors sandwiched to provide a monolithic panel system which supports the floorboards with optimum rigidity and integrity at a reduced cost. The upper subfloor has grooves milled in the bottom surface with flat clinching strips received within the grooves. The floorboards are disposed above the upper subfloor and secured thereto by a plurality of clinching nails extending through the florboards, the upper subfloor and into the upper subfloor after deflecting on said clinching strips.

Expressions giving the velocity level difference between bottom and top plates are derived. Calculated and measured values are compared. The frequency dependence of the level difference is found to be between 25 and 40 dB/decade. The slope of the curve depends on the material parameters for the floor. Radiation ratios and reduction indices for some floating‐deck constructions are also discussed.

This paper describes a procedure for calculating the impact‐noise level of a bare stiff structural floor when excited with a standard tapping machine. Calculations are also given for the improvement in impact noise isolation achieved by adding to the structural floor (a) an elastic surface layer, (b) a locally reacting floating floor, and (c) a resonantly reacting floating floor.

The fundamental method of calculating sound insulation for various kinds of slab materials is described theoretically, based on the assumptions that there is a well‐diffused bending wave field in a floor slab and that the impact‐force power spectrum of the tapping machine depends on floor covering and slab materials, while that of the tire is assumed not to depend on these materials. After proving on the basis of many kinds of experimental results that these assumptions do not matter in practical application of the calculating method, the total assessment system that is provided for the purpose of the JIS evaluation indexes is shown. These indexes can be obtained from the two types of impact‐sound level, caused by a tire or tapping machine, and the inverse A curve. Using the assessment system, many kinds of practical floor constructions, such as bare concrete slab, floating floor, and timber joist floor, are classified on a matrix of the two L values.

An air-borne and footstep noise insulating panel of synthetic resin foam is provided for floating floor pavements or floating wooden floors, said panel having in the interior thereof a multiplicity of voids extending normal or obliquely from one panel edge to the opposite panel edge. The panel preferably consists of a flexible closed-cell synthetic resin foam having a volume weight of 15 to 25 kg/m3, especially less than 20 kg/m3, having a cell diameter of less than 0.3 mm, and exhibiting good elastic recovery. The insulating panel has a dynamic stiffness, measured according to DIN 52214, of 1 to 13 MN/m3 and also possesses the required properties regarding long-term, burning, and insulating behavior.

Neoprene mountings are primarily used for vibration isolation of mechanical equipment and floating floor constructions. The composition of a neoprene mounting has a direct influence on its ability to reduce vibration transmission and attain a specific natural frequency for vibration isolation. The standard characteristic of static loading is not the only parameter for selecting a neoprene mounting. Dynamic stiffness [static deflection/dynamic deflection] is more useful. We have tested two sets of neoprene mountings—30, 40, 50, 60, and 70 durometer each. The results of our tests indicated that the amount of carbon black and the chemical composition of the neoprene had a direct bearing on the change in the dynamic stiffness.

Based on the results presented in the preceding paper, an expression connecting the impact‐noise level (Ln) and sound transmission loss (TL) of a floor is derived that takes into account both the resonant and the forced response of the floor; it thus extends the utility of the formulas derived previously by Heckl and Rathe into the frequency range below the critical frequency. It is shown how this connection between impact‐noise level and sound TL can be used for the experimental evaluation of the potential TL of a floating floor in the presence of certain types of flanking.

The dynamic stiffness of a number of elastic mounts commonly used in floating floor applications was measured as a function of the static load. The paper reports on the measurement method and on the measured data obtained. The measurements indicated that the dynamic stiffness for cork, neoprene, and precompressed glass fiber mounts increases with increasing static load. The dynamic stiffness was found to be independent of frequency in the region of from 20 Hz to 2 kHz. An inspection of the static‐load deflection curves indicated that the tangent of the static‐load deflection curves does not agree with the measured dynamic stiffness, the latter being 2 to 3 times larger. [The work was supported by the Korfund Dynamics Corporation.]

This paper describes a procedure for calculating the impact‐noise level of the sound that would be radiated by a bare, stiff structural floor into the reverberant receiving room below, when excited with a standard tapping machine. Calculations are also given for the improvement in impact noise isolation achieved by adding: (a) an elastic surface layer, (b) a locally reacting floating floor, and (c) a resonantly reacting floating floor, to the structural floor.