ISO/TC 43/SC 2 - Building acoustics

This document specifies a method for the measurement of room acoustic parameters in unoccupied open-plan offices. It specifies measurement procedures, the apparatus needed, the coverage required, the method for evaluating the data, and the presentation of the test report. This document describes a group of single-number quantities indicating the room acoustic performance of an open-plan office in a condition when one person is speaking. They focus on spatial decay of speech while the quantities in ISO 3382-2 focus on temporal decay of sound.

This document specifies differentiated criteria for acoustic conditions and characteristics for rooms and spaces used for music rehearsal. The criteria are specified for different types of music, regardless of the type of building in which the spaces are located. The document provides criteria for room acoustics in spaces used for music rehearsal, whether this is the primary use of the spaces or they are multi-purpose spaces. Together with the acoustic criteria, requirements are given for net room height, net room volume and net area. Criteria for acoustic conditions are differentiated on the basis of three music types: amplified music, quiet acoustic music, and loud acoustic music. This document is applicable to the planning of new buildings and the refurbishment of existing ones. The document can also be used to assess the suitability of existing spaces for different musical purposes. The document can be used for the adjustment of rooms and spaces whose primary purpose is not music rehearsal such as sports halls, classrooms, assembly halls, multi-purpose rooms, etc. Flexible acoustic solutions can be used in order to cover several purposes of use. The criteria in this document do not apply to large, specialized concert halls, opera venues and similar spaces which are basically designed for concerts and performances, or specialized music recording studios. The document does not deal with the need for logistics, storage rooms for instruments and other key support functions relating to music rehearsal. Sound insulation criteria are not included in this document.

This document specifies field survey methods for measuring a) airborne sound insulation between rooms, b) impact sound insulation of floors, c) airborne sound insulation of façades, and d) sound pressure levels in rooms caused by service equipment. The methods described in this document are applicable for measurements in rooms of dwellings or in rooms of comparable size with a maximum of 150 m3. For airborne sound insulation, impact sound insulation and façade sound insulation the method gives values which are (octave band) frequency dependent. They can be converted into a single number characterising the acoustical performances by application of ISO 717-1 and ISO 717-2. For heavy/soft impact sound insulation, the results also are given as A-weighted maximum impact sound pressure level. For service equipment sound the results are given directly in A - or C -weighted sound pressure levels.

This document specifies test requirements for the laboratory measurement of the sound insulation of building elements and products, including detailed requirements for the preparation and mounting of the test elements, and for the operating and test conditions. It also specifies the applicable quantities, and provides additional test information for reporting. The general procedures for airborne and impact sound insulation measurements are given in ISO 10140‑2 and ISO 10140-3, respectively.

This document describes criteria and procedures for acoustic classification of dwellings. The purpose of this document is to make it easier for developers to specify a classified level of acoustic quality for a dwelling, and help users and builders to be informed about the acoustic conditions and define increased acoustic quality. The document can also be applied as a general tool to characterize the quality of the existing housing stock and includes provisions for classifying the acoustic quality before and after renovation has taken place. By the acoustic quality for a dwelling is understood the quality of the acoustic performances typically included in building regulations, e.g. sound insulation towards neighbouring premises and road traffic as well as sound from service equipment. Sound insulation and room acoustics internally in a dwelling are not included in the acoustic classes defined. This document does not have a legal status in a country, unless decided by its own authorities. However, an additional purpose of this document is to help national authorities and standardization organisations to develop or revise national building regulations and acoustic classification schemes. For the purpose of this document, the term ”dwellings” refers to detached and attached dwelling-houses, buildings with several flats as well as individual dwellings, and a dwelling is the living space for a household.

This document specifies laboratory methods for measuring the impact sound insulation of floor assemblies. The test results can be used to compare the sound insulation properties of building elements, classify elements according to their sound insulation capabilities, help design building products which require certain acoustic properties and estimate the in situ performance in complete buildings. The measurements are performed in laboratory test facilities in which sound transmission via flanking paths is suppressed. The results of measurements made in accordance with this document are not applicable directly to the field situation without accounting for other factors affecting sound insulation, such as flanking transmission, boundary conditions, and loss factor. A test method is specified that uses the standard tapping machine (see ISO 10140-5:2021, Annex E) to simulate impact sources like human footsteps when a person is wearing shoes. Alternative test methods, using a modified tapping machine or a heavy/soft impact source (see ISO 10140-5:2021, Annex F) to simulate impact sources with strong low frequency components, such as human footsteps (bare feet) or children jumping, are also specified. This document is applicable to all types of floors (whether heavyweight or lightweight) with all types of floor coverings. The test methods apply only to laboratory measurements.

This document specifies laboratory test facilities and equipment for sound insulation measurements of building elements, such as: — components and materials; — building elements; — technical elements (small building elements); — sound insulation improvement systems. It is applicable to laboratory test facilities with suppressed radiation from flanking elements and structural isolation between source and receiving rooms. This document specifies qualification procedures for use when commissioning a new test facility with equipment for sound insulation measurements. It is intended that these procedures be repeated periodically to ensure that there are no issues with the equipment and the test facility.

This document specifies the basic measurement procedures for airborne and impact sound insulation of building elements in laboratory test facilities.

This document specifies a laboratory method for measuring the airborne sound insulation of building products, such as walls, floors, doors, windows, shutters, façade elements, façades, glazing, small technical elements, for instance transfer air devices, airing panels (ventilation panels), outdoor air intakes, electrical raceways, transit sealing systems and combinations, for example walls or floors with linings, suspended ceilings or floating floors. The test results can be used to compare the sound insulation properties of building elements, classify elements according to their sound insulation capabilities, help design building products which require certain acoustic properties and estimate the in situ performance in complete buildings. The measurements are performed in laboratory test facilities in which sound transmission via flanking paths is suppressed. The results of measurements made in accordance with this document are not applicable directly to the field situation without accounting for other factors affecting sound insulation, such as flanking transmission, boundary conditions and total loss factor.

This document a) defines single-number quantities for airborne sound insulation in buildings and of building elements such as walls, floors, doors, and windows, b) takes into consideration the different sound level spectra of various noise sources such as noise sources inside a building and traffic outside a building, and c) gives rules for determining these quantities from the results of measurements carried out in one-third-octave or octave bands for example in accordance with ISO 10140-2 and ISO 16283-1. The single-number quantities in accordance with this document are intended for rating airborne sound insulation and for simplifying the formulation of acoustical requirements in building codes. An additional single-number evaluation in steps of 0,1 dB is indicated for the expression of uncertainty (except for spectrum adaptation terms). The required numerical values of the single-number quantities are specified according to varying needs. The single-number quantities are based on results of measurements in one-third-octave bands or octave bands. For laboratory measurements made in accordance with ISO 10140-2, single-number quantities are calculated using one-third-octave bands only. The rating of results of measurements carried out over an enlarged frequency range is dealt with in Annex B.

This document a) defines single-number quantities for impact sound insulation in buildings and of floors, b) gives rules for determining these quantities from the results of measurements carried out in one-third-octave bands in accordance with ISO 10140-3 and ISO 16283-2, and in octave bands in accordance with that option in ISO 16283-2 for field measurements only, c) defines single-number quantities for the impact sound reduction of floor coverings and floating floors calculated from the results of measurements carried out in accordance with ISO 10140-3, and d) specifies a procedure for evaluating the weighted reduction in impact sound pressure level by floor coverings on lightweight floors. The single-number quantities in accordance with this document are intended for rating impact sound insulation and for simplifying the formulation of acoustical requirements in building codes. An additional single-number evaluation in steps of 0,1 dB is indicated where it is needed for the expression of uncertainty (except for spectrum adaptation terms). Numerical values of the single-number quantities are specified where required for calculations. The rating of measurements over an enlarged frequency range is given in Annex A. A method for obtaining single-number quantities for bare heavy floors according to their performance in combination with floor coverings is given in Annex B. Example calculations of single-number quantities are given in Annex C. The rating of measurements with a heavy and soft impact source (rubber ball) is given in Annex D.

This document specifies an alternating airflow method for the determination of the airflow resistance[5], [6] of porous materials for acoustical applications. Determination of the airflow resistance based on static flow is described in ISO 9053‑1.

This document specifies measurement methods to characterize in the laboratory the acoustic radiation of a building element when it is directly excited by an airborne or structure-borne source. It is applicable to single-leaf and double-leaf elements (see ISO 12354-1:2017 Annex F, F2). The measured quantity can be used as input data for prediction methods, such as ISO 12354-1 and ISO 12354-2, to compare products, or to express a requirement.

This document specifies procedures to determine the impact sound insulation using sound pressure measurements with an impact source operating on a floor or stairs in a building. These procedures are intended for room volumes in the range from 10 m3 to 250 m3 in the frequency range from 50 Hz to 5 000 Hz. The test results can be used to quantify, assess and compare the impact sound insulation in unfurnished or furnished rooms where the sound field may or may not approximate to a diffuse field.

This document specifies a laboratory method to facilitate the comparison of furniture ensembles and enclosures with respect to their ability to reduce the speech level of the occupant speaking inside the product. In this method, the sound power level is measured in two scenarios: 1) without the product, and 2) with the product. During scenario 1), the test signal is produced by the sound source in an empty room while the product is absent. During scenario 2), the test signal is produced by the sound source inside the product in the occupant's position. Level reduction is the difference of the sound power levels measured in the two scenarios in 1/1-octave frequency bands from 125 Hz to 8 000 Hz. Speech level reduction is a single-number quantity that expresses the corresponding reduction in A-weighted sound power level of standard speech within the entire frequency range from 125 Hz to 8 000 Hz. The method is applicable for entire furniture ensembles or enclosures, which form a unity that serves one or several occupants, and which are also used to provide improved speech privacy. This method is not intended for single components used in workstations, such as a screen, a storage unit, a table, a luminaire, a cupboard, a bookshelf, a standard chair, a wall absorber or a ceiling absorber.

This document specifies how to calculate: — the uncertainty of sound absorption coefficients and equivalent sound absorption areas measured according to ISO 354; — the uncertainty of the practical and weighted sound absorption coefficients determined according to ISO 11654; — the uncertainty of the object sound absorption coefficient according to ISO 20189; and — the uncertainty of the single number rating determined according to EN 1793‑1. Furthermore, the use of uncertainties in reporting measured or weighted sound absorption coefficients is explained.

This document specifies procedures for assessing the measurement uncertainty of sound insulation in building acoustics. It provides for — a detailed uncertainty assessment; — a determination of uncertainties by inter-laboratory tests; — an application of uncertainties. Furthermore, typical uncertainties are given for quantities determined according to ISO 10140 (all parts), ISO 16283 (all parts) and ISO 717 (all parts).

This document specifies how screens, furniture and single objects intended for interior use are assessed with regard to sound absorption and specifies the evaluation of sound attenuation for floor screens. It also specifies under which circumstances various interior products for offices, schools and other public spaces are considered as plane absorbers or as discrete single objects. A product considered as a single object and intended for interior use is measured according to ISO 354 and evaluated by its equivalent sound absorption area or object sound absorption coefficient in octave bands. This document defines interior products and single objects and it comprises additional information regarding measurements and assessment of single objects. The sound absorption as specified in this document can be used to calculate: a) reverberation time characteristics in rooms; b) room acoustic parameters using ray tracing software.

This document specifies the measurement of the determination of the static airflow resistance[1,2], in a laminar flow regime, of porous materials for acoustical applications.

ISO 3822-3:2018 specifies the mounting and operating conditions to be used for in-line valves and appliances which control the flow, pressure or temperature of the water in water supply installations, when measuring noise emission resulting from water flow. ISO 3822-3:2018 is applicable to in-line valves and appliances of maximum nominal size DN 32 and to systems in which the maximum water flow rate does not exceed 1,6 l/s. NOTE See ISO 6708; DN is the symbol for "nominal size". The number of the nominal size is loosely related to the inside diameter (in millimetres) of the in-tine valves and appliances. The procedures described are for general use for all types of in-line valves of conventional design.

ISO 10848 (all parts) specifies measurement methods to characterize the flanking transmission of one or several building components. This document considers only laboratory measurements. The measured quantities can be used to compare different products, or to express a requirement, or as input data for prediction methods, such as ISO 12354‑1 and ISO 12354‑2. However, the measured quantities Dn,f, Ln,f and Lne0,f only represent the performance with the dimensions for the test specimens described in this document. ISO 10848-2:2017 is referred to in ISO 10848‑1:2017, 4.5 as being a supporting part of the frame document. It applies to Type B elements as defined in ISO 10848‑1, such as suspended ceilings, access floors, light uninterrupted façades or floating floors. The transmission from one room to another can occur simultaneously through the test element and via the plenum (if any). For measurements made according to this document, the total sound transmission is determined and it is not possible to separate the two kinds of transmission.

ISO 10848 (all parts) specifies measurement methods to characterize the flanking transmission of one or several building components. ISO 10848-3:2017 specifies laboratory and field measurements of buildings for Type B elements (defined in ISO 10848‑1) when the junction has a substantial influence. Laboratory measurements are used to quantify the performance of the junction with suppressed flanking transmission from the laboratory structure. Field measurements are used to characterize the in situ performance and it is not usually possible to suppress unwanted flanking transmission sufficiently; hence, the results can only be considered representative of the performance of that junction when installed in that particular building structure. ISO 10848-3:2017 is referred to in ISO 10848‑1:2017, 4.5 as being a supporting part to the frame document and applies to Type B elements that are structurally connected as defined in ISO 10848‑1. The measured quantities can be used to compare different products, or to express a requirement, or as input data for prediction methods, such as ISO 12354‑1 and ISO 12354‑2. The relevant quantity to be measured is selected according to ISO 10848‑1:2017, 4.5. The performance of the building components is expressed either as an overall quantity for the combination of elements and junction (such as Dn,f,ij and/or Ln,f,ij and/or Lne0,f,ij) or as the normalized direction-average velocity level difference of a junction. Dn,f,ij, Ln,f,ij, Lne0,f,ij and depend on the actual dimensions of the elements.

ISO 10848 (all parts) specifies measurement methods to characterize the flanking transmission of one or several building components. These measurements are performed in a laboratory test facility or in the field. The performance of the building components is expressed either as an overall quantity for the combination of elements and junction (such as the normalized flanking level difference and/or normalized flanking impact sound pressure level) or as the vibration reduction index of a junction or the normalized direction-average vibration level difference of a junction. Two approaches are used for structure-borne sound sources in buildings, a normalized flanking equipment sound pressure level and a transmission function that can be used to estimate sound pressure levels in a receiving room due to structure-borne excitation by service equipment in a source room. The former approach assumes that flanking transmission is limited to one junction (or no junction if the element supporting the equipment is the separating element), and the latter considers the combination of direct (if any) and all flanking transmission paths. ISO 10848-1:2017 contains definitions, general requirements for test elements and test rooms, and measurement methods. Guidelines are given for the selection of the quantity to be measured, depending on the junction and the types of building elements involved. Other parts of ISO 10848 specify the application for different types of junction and building elements. The quantities characterizing the flanking transmission can be used to compare different products, or to express a requirement, or as input data for prediction methods, such as ISO 12354‑1 and ISO 12354‑2.

ISO 10848 (all parts) specifies measurement methods to characterize the flanking transmission of one or several building components. ISO 10848-4:2017 specifies laboratory and field measurements of buildings where at least one of the elements that form the construction under test is a Type A element (defined in ISO 10848‑1). Laboratory measurements are used to quantify the performance of the junction with suppressed flanking transmission from the laboratory structure. Field measurements are used to characterize the in situ performance and it is not usually possible to suppress unwanted flanking transmission sufficiently; hence, the results are primarily representative of the performance of that junction when installed in that particular building structure. The measured quantities can be used to compare different products, or to express a requirement, or as input data for prediction methods, such as ISO 12354‑1 and ISO 12354‑2.

ISO 12354-4:2017 specifies a calculation model to estimate the sound power level radiated by the envelope of a building due to airborne sound inside that building, primarily by means of measured sound pressure levels inside the building and measured data which characterize the sound transmission by the relevant elements and openings in the building envelope. These sound power levels, together with those of other sound sources in or in front of the building envelope, form the basis for the calculation of the sound pressure level at a chosen distance from a building as a measure for the acoustic performance of buildings. The prediction of the inside sound pressure level from knowledge of the indoor sound sources is outside the scope of this document. The prediction of the outdoor sound propagation is outside the scope of this document. NOTE For simple propagation conditions an approach is given for the estimation of the sound pressure level in Annex E. ISO 12354-4:2017 describes the principles of the calculation model, lists the relevant quantities and defines its applications and restrictions.

ISO 12354-2:2017 specifies calculation models designed to estimate the impact sound insulation between rooms in buildings, primarily using measured data which characterize direct or indirect flanking transmission by the participating building elements and theoretically-derived methods of sound propagation in structural elements. A detailed model is described for calculation in frequency bands, in the frequency range 1/3 octave 100 Hz to 3150 Hz in accordance with ISO 717‑1, possibly extended down to 1/3 octave 50 Hz if element data and junction data are available (see Annex E); the single number rating of buildings can be determined from the calculation results. A simplified model with a restricted field of application is deduced from this, calculating directly the single number rating, using the single number ratings of the elements; the uncertainty on the apparent impact sound pressure level calculated using the simplified model can be determined according to the method described in ISO 12354‑1:2017, Annex K (see Clause 5). ISO 12354-2:2017 describes the principles of the calculation scheme, lists the relevant quantities and defines its applications and restrictions.

ISO 12354-3:2017 specifies a calculation model to estimate the sound insulation or the sound pressure level difference of a façade or other external surface of a building. The calculation is based on the sound reduction index of the different elements from which the façade is constructed and it includes direct and flanking transmission. The calculation gives results which correspond approximately to the results from field measurements in accordance with ISO 16283‑3. Calculations can be carried out for frequency bands or for single number ratings. The calculation results can also be used for calculating the indoor sound pressure level due to for instance road traffic (see Annex E). ISO 12354-3:2017 describes the principles of the calculation model, lists the relevant quantities and defines its applications and restrictions.

ISO 12354-1:2017 specifies calculation models designed to estimate the airborne sound insulation between adjacent rooms in buildings, primarily using measured data which characterize direct or indirect flanking transmission by the participating building elements, and theoretically-derived methods of sound propagation in structural elements. A detailed model is described for calculation in frequency bands, in the frequency range 1/3 octave 100 Hz to 3 150 Hz in accordance with ISO 717‑1, possibly extended down to 1/3 octave 50 Hz if element data and junction data are available (see Annex I); the single number rating can be determined from the calculation results. A simplified model with a restricted field of application is deduced from this, calculating directly the single number rating, using the single number ratings of the elements; a method to determine uncertainty is proposed for the simplified model (see Annex K). ISO 12354-1:2017 describes the principles of the calculation scheme, lists the relevant quantities and defines its applications and restrictions.

ISO 16283-3:2016 specifies procedures to determine the airborne sound insulation of façade elements (element methods) and whole façades (global methods) using sound pressure measurements. These procedures are intended for room volumes in the range from 10 m3 to 250 m3 in the frequency range from 50 Hz to 5 000 Hz. The test results can be used to quantify, assess, and compare the airborne sound insulation in unfurnished or furnished rooms where the sound field can or cannot approximate to a diffuse field. The measured airborne sound insulation is frequency-dependent and can be converted into a single number quantity to characterize the acoustic performance using the rating procedures in ISO 717-1.

ISO 16251-1:2014 specifies a laboratory measurement method to determine the improvement of impact sound insulation by a floor covering when laid on a standard concrete floor mock-up and excited by a standard tapping machine. The method is restricted to soft, flexible floor coverings, which transmit impact sound mainly "locally" into the floor, i.e. through the area close to the points of excitation, so that the size of the flooring specimen does not have an influence on the results. Examples of such floor coverings are carpets, PVC, and linoleum. These floor coverings correspond to ISO 10140‑1:2010, Annex H, category I. The results only provide information about the noise radiated. A subjective classification of the quality of the floor coverings is not intended. ISO 16251-1:2014 provides the measurement method. Product test codes can contain further requirements concerning the specimens, such as temperature range, the number of test specimens or special mounting conditions.

ISO 16283-1:2014 specifies procedures to determine the airborne sound insulation between two rooms in a building using sound pressure measurements. These procedures are intended for room volumes in the range from 10 m3 to 250 m3 in the frequency range from 50 Hz to 5 000 Hz. The test results can be used to quantify, assess and compare the airborne sound insulation in unfurnished or furnished rooms where the sound field may or may not approximate to a diffuse field. The measured airborne sound insulation is frequency-dependent and can be converted into a single number quantity to characterize the acoustic performance using the rating procedures in ISO 717‑1.

This part of ISO 17497 specifies a method of measuring the directional diffusion coefficient of surfaces. The diffusion coefficient characterizes the sound reflected from a surface in terms of the uniformity of the reflected polar distribution. The diffusion coefficient is a measure of quality designed to inform producers and users of surfaces that, either deliberately or accidentally, diffuse sound. It can also inform developers and users of geometric room acoustic models. The diffusion coefficient is not suitable for direct use as an input to current diffusion algorithms in geometric room acoustic models. This part of ISO 17497 details a free-field characterization method.

ISO 3382-1:2009 specifies methods for the measurement of reverberation time and other room acoustical parameters in performance spaces. It describes the measurement procedure, the apparatus needed, the coverage required, and the method of evaluating the data and presenting the test report. It is intended for the application of modern digital measuring techniques and for the evaluation of room acoustical parameters derived from impulse responses.

ISO 3382-2:2008 specifies methods for the measurement of reverberation time in ordinary rooms. It describes the measurement procedure, the apparatus needed, the required number of measurement positions, and the method for evaluating the data and presenting the test report. The measurement results can be used for correction of other acoustic measurements, e.g. sound pressure level from sound sources or measurements of sound insulation, and for comparison with requirements for reverberation time in rooms.

ISO 18233:2006 gives guidelines and specifies requirements for the application of new methods for the measurement of the acoustic properties of buildings and building elements. Guidelines and requirements for selection of the excitation signal, signal processing and environmental control are given, together with requirements for linearity and time-invariance for the systems to be tested. ISO 18233:2006 is applicable to such measurements as airborne sound insulation between rooms and of façades, measurement of reverberation time and other acoustic parameters of rooms, measurement of sound absorption in a reverberation room, and measurement of vibration level differences and loss factor. ISO 18233:2006 specifies methods to be used as substitutes for measurement methods specified in standards covering classical methods, such as ISO 140 (all parts), ISO 3382 (all parts) and ISO 17497-1.

ISO 16032:2004 specifies methods for measuring the sound-pressure level produced by service equipment attached to or installed in buildings. It specifically covers measurements on sanitary installations, mechanical ventilation, heating and cooling service equipment, lifts, rubbish chutes, boilers, blowers, pumps and other auxiliary service equipment, and motor-driven car park doors, but can also be applied to other equipment attached to or installed in buildings. The methods are suitable for rooms with volumes of approximately 300 cubic metres or less in e.g. dwellings, hotels, schools, offices and hospitals. The standard is not in general intended for measurements in large auditoria such as concert halls. However, the operating conditions and operating cycles in Annex B can be used in such cases. The service equipment sound-pressure level is determined as the maximum A-weighted and optionally C-weighted sound-pressure level occurring during a specified operation cycle of the service equipment under test, or as the equivalent continuous sound-pressure level determined with a specified integration time. A-weighted and C-weighted values are calculated from octave-band measurements.

ISO 17497-1:2004 specifies a method of measuring the random-incidence scattering coefficient of surfaces as caused by surface roughness. The measurements are made in a reverberation room, either in full scale or on a physical scale model. The measurement results can be used to describe how much the sound reflection from a surface deviates from a specular reflection. The results obtained can be used for comparison purposes and for design calculations with respect to room acoustics and noise control. The method is not intended for characterizing the spatial uniformity of the scattering from a surface.

ISO 15186-2:2003 specifies a sound intensity method to determine the in-situ sound insulation of walls, floors, doors, windows and small building elements. It is intended for measurements that have to be made in the presence of flanking transmission. It can be used to provide sound power data for diagnostic analysis of flanking transmission or to measure flanking sound insulation parameters. ISO 15186-2:2003 can be used by laboratories that could not satisfy the requirements of ISO 15186-1, which deals with laboratory measurements with no or little flanking transmission. ISO 15186-3 deals with measurements under laboratory conditions, at low frequencies. ISO 15186-2:2003 also describes the effect of flanking transmission on measurements made using the specified method, and how intensity measurements can be used -- to compare the in-situ sound insulation of a building element with laboratory measurements where flanking has been suppressed (i.e. ISO 140-3), -- to rank the partial contributions for building elements, and -- to measure the flanking sound reduction index for one or more transmission paths (for validation of prediction models such as those given in EN 12354-1). This method gives values for airborne sound insulation, which are frequency dependent. They can be converted into a single number, characterizing the acoustic performance, by application of ISO 717-1. The reproducibility of this intensity method is estimated to be equal to or better than that of the methods of ISO 140-10 and ISO 140-4, when measuring a single small and large building element, respectively.

ISO 354:2003 specifies a method of measuring the sound absorption coefficient of acoustical materials used as wall or ceiling treatments, or the equivalent sound absorption area of objects, such as furniture, persons or space absorbers, in a reverberation room. It is not intended to be used for measuring the absorption characteristics of weakly damped resonators. The results obtained can be used for comparison purposes and for design calculation with respect to room acoustics and noise control.

ISO 15186-3:2002 specifies a sound intensity method to determine the sound reduction index and the element-normalized level difference of building elements at low frequencies. This method has significantly better reproducibility in a typical test facility than those of ISO 140-3, ISO 140-10 and ISO 15186-1. The results are more independent of the room dimensions of the laboratory and closer to values that would be measured between rooms of volume greater than 300 m3. ISO 15186-3 is applicable in the frequency range 50 Hz to 160 Hz but is mainly intended for the frequency range 50 Hz to 80 Hz. NOTE For elements faced with thick, porous absorbers, the recommended frequency range is 50 Hz to 80 Hz. The main differences between the methods of ISO 15186-1 and ISO 15186-3 are that in ISO 15186-3 the sound pressure level of the source room is measured close to the surface of the test specimen, and the surface opposite the test specimen in the receiving room is highly absorbing and converts the room acoustically into a duct with several propagating cross-modes above the lowest cut-on frequency. The results found by the method of ISO 15186-3 can be combined with those of ISO 140-3 and ISO 15186-1 to produce data in the frequency range 50 Hz to 5 000 Hz. The reproducibility of this intensity method is, for all frequencies, estimated to be equal to or better than that found with the method of ISO 140-3 at 100 Hz. Some comparisons of data obtained with this part of ISO 15186 and with ISO 140-3 are given for information.

This test method covers the use of an impedance tube, two microphone locations and a digital frequency analysis system for the determination of the sound absorption coefficient of sound absorbers for normal sound incidence. It can also be applied for the determination of the acoustical surface impedance or surface admittance of sound absorbing materials. Since the impedance ratios of a sound absorptive material are related to its physical properties, such as airflow resistance, porosity, elasticity and density, measurements described in this test method are useful in basic research and product development. The test method is similar to the test method specified in ISO 10534-1 in that it uses an impedance tube with a sound source connected to one end and the test sample mounted in the tube at the other end. However, the measurement technique is different. In this test method, plane waves are generated in a tube by a noise source, and the decomposition of the interference field is achieved by the measurement of acoustic pressures at two fixed locations using wall-mounted microphones or an in-tube traversing microphone, and subsequent calculation of the complex acoustic transfer function, the normal incidence absorption and the impedance ratios of the acoustic material. The test method is intended to provide an alternative, and generally much faster, measurement technique than that of ISO 10534-1. Compared with the measurement of the sound absorption in a reverberation room according to the method specified in ISO 354, there are some characteristic differences. The reverberation room method will (under ideal conditions) determine the sound absorption coefficient for diffuse sound incidence, and the method can be used for testing of materials with pronounced structures in the lateral and normal directions. However, the reverberation room method requires test specimens which are rather large, so it is not convenient for research and development work, where only small samples of the absorber are available. The impedance tube method is limited to parametric studies at normal incidence but requires samples of the test object which are of the same size as the cross-section of the impedance tube. For materials that are locally reacting, diffuse incidence sound absorption coefficients can be estimated from measurement results obtained by the impedance tube method. For transformation of the test results from the impedance tube method (normal incidence) to diffuse sound incidence, see annex F.

Gives the mounting and operating conditions to be used for a number of in-line valves and appliances, when measuring the noise emission resulting from water flow. Replaces the first edition.