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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.

The sound insulation performance of extruded panels used in railway vehicles is critical to control the interior noise, especially in the case of floor panels. To reduce the mass of floating floors and increase its sound insulation performance, a lightweight design instruction approach has been proposed based on the vibration response of each component of the floating floor structures. The total height, length, thickness of the top layer, thickness of the ribs, and thickness of the bottom layer in the typical cross section of the exterior floor are used as variables; the mass of the typical cross section and the averaged sound transmission loss (STL) results in 1/3 octave bands centred from 400 to 3150 Hz are used as the optimisation targets; the optimal result of the smallest mass and the largest averaged STL are achieved in commercial software VA One and Isight. The effect of this optimisation scheme on the sound insulation performance of the floating floor is analysed based on the verified STL prediction model. After this optimisation, the results indicate that the mass of the exterior floor structure is reduced by 15.2% compared with the original exterior floor structure, and the averaged STL in 1/3 octave bands centred from 400 to 3150 Hz and the weighted STL of the floating floor are increased by 0.8 dB and 1 dB, respectively.

An effective way to reduce impact sound in buildings is to install a floating floor consisting of a floating slab separated from the structural slab by a continuous viscoelastic layer. Although a considerable amount of work has been reported on nanomaterials in the past decades, the impact sound reduction performance of polymer/clay nanocomposites has not been specifically addressed in the literature. In this paper, we report the synthesis and characterization of a nanocomposite made of thermoplastic polyurethane (TPU) with laponite clay filler and its potential use for reducing impact sound in floating floor technology. Samples were prepared with laponite content ranged between 0.5 and 10 wt% for each nanocomposite synthesized using a solvent solution mixing process. The characterization of the nanocomposites confirmed that the clay content in the TPU matrix has significant impact on the viscoelastic properties. In particular, the incorporation of 5–10 wt% laponite clay in the TPU matrix increased mechanical damping and reduced dynamic stiffness as compared to the pristine TPU. The experimental results were compared with a constitutive model that extends the Cremer-Ver model. The results predicted a considerable improvement of the impact sound insulation at the resonance frequency when the nanocomposite is used as a continuous viscoelastic layer supporting the floating slab. These results were attained without significantly increasing the total weight of the floating layer.

In today’s apartment houses, adoption of floating floor has vastly improved structure-borne floor impact noise by isolating vibration components well in excess of the major structural vibration resonant frequencies. For 20–200 Hz frequency region encompassing major structural vibratory and room acoustic modes, however, impact noise attenuation is much harder to achieve, and the problem can be exacerbated for small rooms where these modes are sparsely placed in audible frequency range. Experimental and numerical investigation of the effect of structural vibration and room acoustics on impact noise for the frequency region is undertaken. Structural vibration modes of the room with floating floor correlate well with the spectral characteristics of the impact noise, with various structural parts making different contributions in the frequency domain. For the low end of the impact noise spectrum, low density of high-energy axial room acoustic modes arising from small room size causes sound field in the room to show notable variation with measurement locations. For the mock-up typical of a small-sized living room considered in the present study, one of the vibrational mode of floor slab excites an overlapping fundamental room acoustic mode that further amplifies the impact noise. A room design that avoids overlapping of major structural and acoustic resonance modes at low end of the audible spectrum could be crucial in abating an echo commonly encountered in bare apartment rooms.

The primary aim of the presented research is to introduce a new approach based on the probabilistic analysis, which provides an accurate prediction for the improvement of the impact sound pressure level of a floating floor considering the uncertainty of material parameters. The theoretical background of the novel method was provided. It embraces two theorems describing the propagation of uncertainty of a random variables function. The introduced technique leads to the determination of the probability density function of a considered output parameter based on the joint distribution of an input random vector. Secondly, the algorithm was applied to investigate the insulation improvement of an exemplary floating floor. The considered construction was composed of extruded polystyrene as a resilient material and cement screed as a floating slab. The dynamic stiffness and the loss factor of the resilient layer and the density of cement screed served as input variable parameters with Gaussian distributions. The probabilistic analysis was based on two models providing the insulation improvement of a floating floor, e.g., Cremer-Ver formula and the recently proposed transmissibility model. Finally, the accuracy of the described methodology was verified by comparing it to the results obtained by Monte Carlo, performing 106 simulations. Additionally, we introduced a simplified model using the linearization of the Cremer-Ver relation, which can be applied to determine the probability density of sound insulation improvement for floating floor composed of XPS and cement screed in a simple and efficient way.

Floating floors have a high potential for reducing disturbance by impact noises in dwellings, since it greatly reduces the vibrations transmission through structures. The acoustical performance of a floating floor is quantified in terms of improvement of impact sound insulation Δ L. The improvement of impact sound insulation of a floating floor is a key parameter for the calculation of structure-borne sound insulation in buildings. Indeed, once Δ L is known, it is possible to evaluate the impact sound insulation, in in situ conditions, for several base floors of different building technologies and materials. Δ L can be directly determined on the basis of standard laboratory measurements, but it can be also estimated from elastic and inertial properties of involved materials, such as stiffness and mass. In this paper a constitutive model for the estimation of floating floors improvement of impact sound insulation is presented. As it will be shown, the constitutive model proposed based on force transmissibility theory, allows to accurately estimate the acoustical behavior of a floating floor, as a function of frequency, with a simple single function. Theoretical assumptions, experimental evidences and comparisons with previous computational models (e.g., Cremer-Ver model) allow to confirm both validity and effectiveness of the proposed 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.

Impact noise is increasingly becoming an important issue both in terms of technologies for its reduction and in terms of its perception inside buildings. In fact, a high level of noise clearly affects indoor comfort and liveability of confined spaces. For this reason, this study focuses on the influence which the screed static load has over time on the resilient material of a floating floor and on its final performance. Five different types of resilient materials have been tested for five years and the results are analysed in terms of material type, surface contact and thickness variation, dynamic stiffness measured on 8 different time steps and its application on 6 different bare floors. Obtained parameters values are therefore studied in terms of perceived comfort and compliance with 31 European countries regulations limits. Results clearly show that time has a paramount influence on all types of resilient materials (with the exception of one) in all configurations and that complete floor selection, in time, can greatly change perceived indoor living comfort and compliance with the limits imposed by laws.

Sound insulation performance of floor is the basic functional requirements of green buildings. However, without special sound insulation design and construction processing, the requirements of sound insulation design indexes are difficult to be met in reality. As a component of space separation, the floor should be emphasized, especially the impact sound insulation performance of the floor. In this paper, the reinforced concrete residential floor is taken as the reference, and the influence factors on the impact sound insulation performance of floor are considered, including type, thickness, mass density and dynamic stiffness of elastic material, and the quality and thickness of floating plate. Besides, construction methods for different series of floating floor are presented, and the impact sound insulation change is studied through theoretical and experimental analysis. This study provides technical support and case experience for the sound insulation and noise reduction design of the floor, so as to improve the sound insulation performance of the floor.

Acoustic performance is a building and users requirement, sometimes neglected, which commonly causes discomfort to the neighborhood. Subfloors with acoustic insulation properties are an alternative to minimize this problem. They are made with different materials types, including industrial wastes, reducing the Construction Industry impact, making it more sustainable. This research aims at assessing, experimentally, different subfloor mortars, with lightweight aggregates, to reduce impact sound, produced from the replacement of different contents of natural aggregate for exfoliated vermiculite and chrome sawdust (waste from tanning industries), in comparison with an industrialized mortar commercialized with acoustic isolation characteristics. The mortars were characterized by national standards, their dynamic stiffness was measured (according to ISO 9052-1) and used to estimate the sound reduction for impact noise (as stated by ISO 12354). Mortars with aggregate substitutions, including the wastes in higher substitution contents, have the potential to become an alternative for impact noises insulation in floating floor systems.

Building multi-dwelling units is one of the practical engineering solutions to housing shortage in urban areas with high population density. However, noise from upstairs is a major issue. The use of resilient materials in floating floor structures is recognized as an effective method to reduce such noise. In general, soft materials are considered as better resilient materials due to their superior performance in impact sound reduction. However, it is often overlooked that the sound reduction performance of soft resilient materials is susceptible to being degraded over time when subjected to a long-term load. In this study, the long-term performance of eight resilient materials is evaluated by monitoring their dynamic stiffness for 270 days under the two sustained load conditions: 250 N and 500 N. According to the experimental study, the dynamic stiffness increases consistently with loading time for all resilient materials. This leads to a decrease in the sound reduction performance. More rapid reduction in the dynamic stiffness and hence in the sound reduction performance is observed when a larger sustained load is applied. A greater decrease in the sound reduction performance is found in soft resilient materials.

The dynamic stiffness of underlays is a required quantity to predict the reduction of impact and airborne noise transmitted through floating floors. The measurement of the dynamic stiffness is standardized in ISO 9052–1 using a floating floor section of 200 mm edge length. If open pore insulating materials are used for the underlay, the air flow and its flow resistivity have a significant impact on the dynamic stiffness. The standard ISO 9052–1 therefore calculates the dynamic stiffness based on three distinct intervals of the flow resistivity. This contribution analyses and discusses the mathematical origin and practical consequences of these three standardized intervals and proposes an improvement for a revision of the standard. The current physical model is expanded to examine if the results, that are gained from the geometrically reduced systems of the standard, can be transferred to room sized systems.

With the increasing demands for indoor comfort, the sound insulation issues of buildings should not be ignored. The impact sound of floors is the main source of noise between rooms. In this study, impact sound insulation tests were performed on one cross laminated timber (CLT) floor and one timber-concrete composite (TCC) floor to investigate the impact sound insulation performance. Since the sound insulation performance of bare floors is poor, effective sound insulation improvement schemes were proposed, including three kinds of solutions of floating floor and two kinds of solutions of suspended ceiling for TCC floor and CLT floor. In addition, an additional optimization solution of floating floor was also presented for CLT floor. The impact sound insulation performance of two floors with different solutions in full frequency range was compared and analyzed. The test results showed that adding floating floor and suspended ceiling can improve the impact sound insulation performance of floors to a certain degree, and the latter is more effective. The experimental and analytical results could provide a reference for improving the sound insulation of residential floors.

Resilient materials are used to reduce vibration transmission in buildings, e.g. in floating floors designed to decrease the impact sound pressure level in the room below the floor. The performance of a floating floor can be estimated in advance knowing the dynamic stiffness per unit area of the resilient material, which is usually measured on a small sample according to ISO 9052-1. Thus, the reliability of results from ISO 9052-1 measurements is crucial. However, the published standard gives few indications on the measuring equipment and suggests measuring the resonance frequency of the fundamental vertical vibration of the test specimen and of the load plate by using either sinusoidal, white noise or pulse signals, considered as equivalent. In this work, a measuring apparatus following the ISO 9052-1 specifications with some hardware and software improvements is described. Then the scanty specifications about the excitation signal are complemented introducing two robust alternatives, compatible with the ISO 9052-1 prescriptions: the ESS (Exponential Swept Sine) and MLS (Maximum Length Sequence) signals. The two newly proposed signals are validated measuring the dynamic stiffness per unit area of different resilient materials, whose resonance frequency is estimated using the same measuring equipment and four different excitation methods: hammer generated impulses, white noise, ESS and MLS. The comparison shows that ESS and MLS signals, already in use since many years for other kinds of acoustic measurements, are viable alternatives to traditional techniques and may have advantages in term of repeatability, dynamic range, cleanness of the frequency response and background noise immunity.

The lightweight floor is a popular construction choice in buildings despite its poor low-frequency impact sound performance. This is exacerbated by common human activities, such as walking and jumping, that have high input force levels at low frequencies. Therefore, experimental evaluations of the low-frequency impact sound performance of a wooden lightweight floor are of interest to designers and researchers. The aim of this paper is to explore the use of heel drop for impact sound transfer measurement. An impact force plate has been built to accurately measure the heel-drop forces up to 200 Hz and the performances on two types of floors are evaluated. The heel drop has a higher energy level at low frequencies, resulting in higher coherence and signal-to-noise ratio and hence superior performance in characterizing the floors in the frequency range of below 40 Hz when compared to the impact hammer. Interestingly, in the case of a heel-drop excitation, the first natural frequencies of the floor decrease. It is in contrast to when a human is simply standing on it, which resulted in an increase of the natural frequencies upon impact hammer excitation.

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.

The dynamic stiffness of a resilient material used under a floating floor is often used to predict the improvement of the impact sound pressure level, ΔL. It is also used to compare products. The measurement accuracy of this parameter is therefore essential. Unfortunately, the comparison between the predicted and the measured ΔL results shows quite high deviations which could be attributed, in part, to an incorrect estimation of the dynamic stiffness. It is now accepted by all European laboratories that the measurement procedure described in the standard ISO 9052-1 should be reviewed. This paper proposes a first step in the improvement of the measurement setup by taking into account the actual contribution of the dynamic stiffness of the air enclosed in the materials on the total dynamic stiffness. A new setup is proposed and some results are presented for products with different airflow resistivities.

This paper is concerned with the analysis of the dependence of low frequency impact sound transmission through floating floor systems on in situ matched resonances. The evidence for the floating floor matched resonances has been found previously considering laboratory and numerical tests for one concrete slab and floating floor with varying resilient layers. In the present paper, considering laboratory and field tests for concrete slabs and floating floors with different plan configurations, this evidence is strengthened as differences between laboratory and field measurements of the impact sound level were negligible for the bare concrete slab but not with the floating floor installed. These results were also confirmed numerically. The analysis indicates that the dependence of low frequency impact sound transmission through floating floor systems on in situ matched resonances should be considered in addition to the conventional single degree of freedom models in order to improve accuracy.

The low frequency vibro-acoustic characteristics of a massive floating floor with continuous resilient layer are investigated with experimental measurements and numerical simulations using a hybrid FEA–SEA method. The results of the study indicate the occurrence of the in situ resonance of the floating floor system, which could be explained by the frequency matching between bending modes of the floating plate and the vibration isolator. The in situ frequency-matched resonance is considered to result in a sharp rise of the low frequency transmissibility of the vibration isolator and the impact sound. The difference between the in situ and the apparent natural frequency of the vibration isolator is assumed to be due to a reduced mass behavior of the floating floor in association with the base floor. It is inferred in the present work that contributing factors in the in situ frequency-matched resonance such as floating plate dimensions, elastic properties of the plate, and the location of an impact might affect the conventional regime of the single degree-of-freedom vibration isolation model for floating floors. The influence of floating plate dimensions on the occurrence of the in situ frequency-matched resonance might be considered as one of the factors affecting the differences in the low frequency impact sound of massive floating floors between laboratory and field measurements.

Lightweight building systems in general suffer from poor sound insulation, especially in the low frequency region. Since no reliable mathematical models that can predict the impact sound pressure level exists, the lightweight building design is to a high extent based upon previous experience and upon measurements. A special difficulty is related to experimental measurements since the variation among identical units must not be neglected. A modern volume based lightweight wooden building concept has here been tested by numerous well controlled measurements, in laboratory as well as in more field like conditions. The volume construction technique offers new possibilities and challenges to improve sound insulation in light weight timber construction. The main purpose was to investigate how different constructional solutions in the floor, like plaster board, mineral wool, elastic glue, dividing board, floating floor etc., affect the sound insulation. Many of the tested modifications resulted in only marginally changed impact sound pressure level but parameters that substantially can improve the sound insulation were found in using elastic glue to mount the floor boards, to install extra board layers and to use floating floors.

In order to obtain reliable estimations of the impact sound insulation between rooms, it is necessary to know the acoustic performance of each element composing the floors. The contribution of the flanking transmissions, the attenuation of floating floors and the weighted normalized impact sound pressure level of the basic structure need to be determined in order to apply the simplified calculation method according to the EN ISO 12354-2 standard. With the aim of verifying the range of validity of the calculation method proposed by the EN ISO 12354-2 standard for typical basic beam floor structures, a research based on on-site measurements was conducted. This paper provides an analysis in terms of spectrum trend, predicted average weighted normalized impact sound pressure level and reduction of impact sound pressure level obtainable with a generic floating floor typology. The study can represent a starting point for a correct estimation of the impact sound insulation in new buildings and renovation plans.

Field measurements of floor impact sounds at low frequencies give poor repeatability due to spatial sampling problems. In this study, the spatial distribution of heavy-weight impact sound pressure levels was investigated by field measurements using heavy/soft impact sources, which have been specified as a standard heavy-weight impact source in 140-11. The results of the present study showed that the vertical and horizontal distribution of measured sound pressure levels showed a significant room mode effect at low frequencies. Among the existing standards for measurement of a heavy-weight impact sound, KS F 2810-2 and JIS A 1440-2 provide an appropriate estimation of the room average sound pressure level for bare slab and floating floor, with respect to a low bias error and 95% confidence interval. The guideline for measurement of a heavy-weight impact source was recently proposed in order to complement the limitations of KS F 2810-2 and JIS A 1440-2, and it has been shown that the guideline appropriately performed in the test building and in living rooms of tested apartment buildings.

In this paper, a new design concept of a lightweight floating ceiling with a special arrangement of stiffener beams and isolators is proposed to enhance vibration isolation performance. The key design parameters of resonant frequency of bending and mode shape factor on vibration transmission are determined with some simple formulae. Structural vibrations and noise radiation are evaluated with finite element models (FEM) for various designs. The optimum ceiling designs are applied in a studio, and field measurements with reliable frequency range of 30–400 Hz are conducted to confirm the theoretical results. The analyses ascertain that four design features ensure the optimum vibration isolation performance: the stiffener beams must be installed at the nodal line of fundamental bending resonance of the plate; smaller panels should be applied instead of a large panel covering the whole area of the ceiling, and joints should be free; the isolators should be placed at the nodal point of the bending mode of the plate; and the fundamental bending resonance frequency must not match the modal critical frequency. The proposed stiffened wooden panel design achieved a noise and vibration reduction of 20 dB in the frequency range of 40–100 Hz, and was better than the performance of a concrete floating floor.

This paper investigates the vibration isolation performance of floating floor and floating box structures to control rail vibration transmission. Simple theoretical and experimental methods are developed to analyze the effects of stiffener beam, mass and arrangement of isolator on the fundamental natural frequency of the flexural vibration of floating floor and box structure. The vibration reduction performances of floating floor and box structure are found to be degraded by flexural vibration of the floor or supporting stiffener beam. From the results of vibration measurements; stiffener beams increase the fundamental natural frequency of flexural vibration of floating floor and enhance vibration isolation. Also they can further alleviate the effect of flexural vibration using optimum isolator arrangement effectively. The proposed floating box design achieved a vibration reduction of 15–30 dB in frequency region of critical rail vibration (30–200 Hz).

In this paper, vibration reduction in ship cabins by using floating floor is studied. Two theoretical models are developed and predicted insertion losses of floating floors are compared to experimental results, where measurements are done in the mock-up built for simulating typical ship cabins. The floating floor consists of upper board and mineral wool, which is in turn laid on the deck plate. The first model (M–S–Plate Model) is that upper plate and mineral wool are assumed as a one-dimensional mass–spring system lying on the simply supported elastic floor. The second model (Wave Model) is that mineral wool is assumed as elastic medium, in which longitudinal wave propagates. The comparisons show that M–S–Plate model is in good agreement with experimental results, while mass–spring model on the rigid floor behaves very poorly in the low frequency ranges, particularly near the natural frequency associated with mass–spring system. On the other hand, the wave model significantly underestimates the insertion loss. It is found that including elastic behavior of the deck plate is essential in improving accuracy of the insertion loss prediction for low frequency range below 100–200 Hz.

In this paper, a new design concept of an isolated honeycomb floor with a special arrangement of isolators is proposed to improve the vibration isolation performance of conventional lightweight cement floor panels in the frequency range of 120–600 Hz. The symmetric bending resonance frequencies and mode shapes of a honeycomb floor panel were identified by a shaker test. The effects on vibration isolation of isolator position and acoustic insulation were then investigated using experimental modal analysis. The analysis suggests that four design features ensure the optimum vibration isolation performance of a square floating honeycomb floor: the floor panel should be small, stiff, and lightweight; the isolators must be placed at the nodal points of the symmetric bending modes of the floor panel; the vibration must be transmitted via the center point of the floor panel; and acoustic insulation material should be installed inside the cavity. The proposed floating floor design achieved a vibration reduction of 20–30 dB in the frequency range of 120–600 Hz. In addition, the proposed floor was found to have a 20 dB lower vibration level at the first bending resonance frequency than the conventional design with isolators that are placed at the edges.

An extensive measurement survey of timber floor constructions has been carried out by the acoustics laboratory of the Belgian Building Research Institute [1]. The basis of this study was the airborne and structure-borne sound insulation measured on a bare joist floor with OSB (Oriented Strand Board) sub floor. By adding different floor toppings and gypsum board ceilings to the basic floor construction, gradual improvements were recorded. A large number of floors are evaluated in the laboratory and formed a database for parametric studies. Improvements due to cavity absorption, floating floors and suspended ceilings were quantified and ranked by effectiveness. Measurement results revealed remarkable differences between floating floor systems. In addition, sound insulation measurements have been performed on joist floors with concrete toppings. The so-called mixed concrete-timber floors provide a higher mechanical resistance. The effect of the bonding and topping type on the airborne and structure borne sound insulation has been examined in the laboratory. The results of this additional research are briefly compared to traditional floor systems and compared with the (future) Belgian standard values. An overall evaluation of the acoustic relevance of timber floor partitions in and between dwellings is also made.

This paper looks at the performance that can be achieved using timber platform floors on concrete floor bases in order to design a platform floor that could provide at least 29dB Δ Lw (both loaded and unloaded) for use in floor constructions described in Approved Document E (2003 Edition). Reconstituted open cell foams were identified as resilient materials that could provide suitable static and dynamic stiffness under lightweight timber floating floors. Using two layers of reconstituted foam a platform floor comprising 22m tongue and grooved chipboard achieved 29dB Δ Lw when loaded, and 30dB Δ Lw unloaded. Indicative tests on double platform floating floors indicated that they may be beneficial in floor designs where negative values of Δ L can not be tolerated due to critical impact sound insulation and structural stability requirements. A double floating floor could use dynamically stiffer resilient materials than would be needed in a single floating floor and still provide the required impact sound insulation and structural stability.

The acoustic behaviour of two building systems, a traditional concrete structure and an innovative one involving expanded polystyrene (EPS) elements have been compared using field measurements. The results indicate that the airborne sound insulation is very similar for both construction methods, whereas impact sound insulation is better for the innovative system. The improvement obtained by introducing polyethylene foams in floating floor constructions has also been investigated for the EPS system using field measurements. Also, the impact sound insulation improvement obtained with two different polyethylene foams has also been analysed by performing laboratory experiments. Whilst both materials are adequate for this application, results indicate that the non cross-linked foam has a better performance.

In this paper a theoretical model to predict bending wave transmission through parallel plates connected by a resilient line is presented. The model is based on the interaction of semi-infinite plates intersecting along an infinite boundary. A full model is developed together with some approximations for the more common cases. The results of the model are then used in a statistical energy analysis (SEA) framework to predict transmission through a chipboard floating floor attached to battens which in turn are supported on a concrete floor. Acoustic transmission through the cavities is also considered. The results show that transmission through the battens is the most important path when there is no resilient layer but that this path is insignificant if any resilient layer is present. A comparison between measured and predicted results gave generally good agreement except at high frequencies when a resilient layer was present.

The most relevant parameter for assessing the acoustical properties of insulation layers for floating floor applications is the dynamic stiffness. Besides the surface mass of the floor plate the dynamic stiffness influences the reduction in impact sound pressure level of a floating floor. According to the formerly German measurement standard DIN 52214 the dynamic stiffness of impact sound insulation materials had to be measured after applying a short-term pre-load of 50 kNm−2. This pre-load does not reflect the conditions in the field and has been withdrawn in EN 29052-I. By comparison of measured field data for floor constructions with estimated data based on measurements with and without pre-load it is shown, that the new measurement procedure in connection with a more detailed estimation of the building element properties leads to a more accurate prediction of impact sound insulation in dwellings.

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.

In order to develop the noise control design for a ship's cabin, a series of acoustic tests were carried out in a large scale noise test facilities with two reverberation rooms and deckhouse mock-up. From the tests, it was found that the combined noise level of a cabin was dominated by the radiated noise from the floor structure, which is a combination of a stiffened steel deck and deck covering. In this paper, the dynamic characteristics of floor structure are firstly identified through the structure-borne noise transmission test in the deckhouse mock-up. Based on the result, multi-layer floating floor systems were applied on the steel deck to reduce the radiated noise from the floor structure. Before the application, numerical simulations using assumed modes and structure-borne noise transmission tests are carried out for the floating floor itself to extract the optimum structure. Finally, the considered floating floor systems were applied in the cabin of deckhouse mock-up and the cabin noise reductions are compared. Through a series of numerical simulations and structure-borne noise transmission tests, it is found that the cabin noise reduction of a multi-layer floating floor can be greatly improved over the entire frequency range if the visco-elastic deck covering is installed between the steel deck and the mineral wool of floating floor

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 floors are widely used to reduce the floor impact noise in ship cabins as well as in multi-dwelling buildings. The most common material for impact absorption in floating floor structure is mineral wool, where high density and sufficient thickness is also needed for fire-resistant requirement in ships. For proper design of floating floors, it is essential to understand how the performance of floating floor is affected by the design parameters such as changes of the mineral wool thickness, density, fiber direction and the use of viscoelastic layer. In this paper, noise reduction performance of the floating floor for use in cruise ship cabin is studied. A mock-up is built by using 6 mm steel plate, and two identical cabins are made of 25 mm sandwich panel inside the steel structure. Various floating floor systems are tested by employing the mock-up. The measurements show that viscoelastic layer is effective when it is used to form a constrained layer. However, viscoelastic layer becomes insignificant when mineral wool is present. It is found that impact noise becomes quieter by 7 dB when fiber direction of the mineral wool is changed from vertical to horizontal, and increasing density of mineral wool from 140 kg/m 3 to 240 kg/m 3 results in an increase of 9 dB. It is also observed that floor SBN (Structure-Borne Noise) is greater than side wall SBN by 10-15 dB up to 2000 Hz, which means that side wall SBN can be neglected in evaluating floor impact noise of ship cabin at frequencies up to 2000 Hz.

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.