With the trend to sustainability and energy efficiency, buildings are being constructed that are attempting to be as ‘green’ as possible. One objective in this form of design is to provide a higher level of interior environmental quality than buildings that use conventional practices. Post Occupancy Evaluations have been carried out on 36 sustainable buildings in 11 different countries. This paper describes and analyses the users’ overall perceptions of the acoustical conditions and the noise sources (in particular noise from colleagues, from other people, and from both inside and outside sources) in these buildings. The results from these analyses showed that people rate the overall interior environment of these sustainable buildings highly. However, the acoustic aspect tended to score rather less well than some other aspects of the interior environment. A strong correlation was found between the occupants’ overall perception of noise and their perception of productivity in the workplace.

The importance of sustainability in all aspects of procurement is gaining momentum in many countries and recently the EC has awarded a contract (QUIESST) to develop not only improved evaluation techniques for acoustic performance of noise reducing devices but also to examine optimisation and sustainability issues. This paper examines some options for “natural” forms of screening surface transport noise that might on the face of it be considered sustainable but until a number of factors are fully considered it is not clear how they compare with manufactured noise barriers. It also considers the psychological benefits of using natural solutions based on the “tranquillity rating prediction tool” recently developed at the University of Bradford.

The acoustical characteristics of a room are traditionally determined using directionless impulse response measurements, the directionless nature of which imposes significant limitations on the kinds of information that can be extracted. Obtaining such information in 3D would permit, for instance, a more detailed analysis of sound reflections to be undertaken. This paper overviews a technique for capturing a room’s impulse response in 3D using a practical mi-crophone array (A-format) and then transforming this data into a Cartesian coordinate system (B-format) so that it can be visualised as an image or video. This 3D impulse response visualisation carries information about sound reflections in terms of sound intensity, spatial orientation and time. A software package has been developed in MATLAB to implement this technique, preliminary results from which will be presented. Enhancements of this 3D visualisation, together with a thorough understanding of the accuracy and robustness of the technique, are the focus of a current study and will be briefly discussed.

The aim of this study was to assess the risk of noise induced hearing loss (NIHL) in shearing and investigate practicable control methods. Woolshed surveys included shed construction data, noise dosimetry and area noise sampling. The noise exposures from 40 personal measurements were all above the 85 dB(A) action level, lying in the range 86-90 dB(A). Shearers had the highest exposure, “near field” noise coming from the action of the cutting edge in the shearing comb, but also from downtubes and gears. Noise for sorters and pressers was contributed to by the stereo system (found in all shearing sheds). Lined sheds seemed to have slightly higher noise levels than unlined sheds. None of the shearing crews had hearing protection available. Redesign of the shearing equipment primarily the handpiece but also the downtubes and gears could potentially reduce the exposure by 2-3 dB(A) and possibly more. In the meantime shearing crews need to wear hearing protection and be subject to audiometric surveillance.

The increase in population worldwide has highlighted the inadequacies of sound insulation in buildings. The problem is particularly evident in medium-high density housing situations, which are projected to become 30% of Auckland’s housing by 2050. This will have implications on occupants’ health, productivity and quality of life. Prevention of sound transmission through walls and ceilings in the lower frequency range of human hearing is particularly important, but is a difficult problem. This problem provides an opportunity to ask the question: Can we design an acoustic insulation system that provides improved sound insulation performance over a conventional system, within this frequency range? This paper outlines an investigation into novel meta-materials known as Locally Resonant Structures. These structures can exhibit acoustic band gaps, or frequency ranges of unusually low sound transmission. One-dimensional mathematical models are used in conjunction with finite element analysis FEA to develop various locally resonant element concepts functional below 1kHz. Acoustic testing is then used to experimentally verify the performance of the elements through comparisons with modelling data. Various resonator elements have shown a peak effective mass up to fifty times greater than their rest mass. Locally resonant structures have increased peak transmission losses by as much as 40dB over that of a non-resonant structure of equivalent area density within the designated frequency range. These resonators can be distributed throughout the wall structure on a scale shorter than the wavelength of structural vibrations in the wall matrix. The resulting system has the potential to provide significantly higher transmission loss at low frequencies than conventional wall systems of similar size and weight. The longer term goal is to determine an effective design of local resonator that can be incorporated into a practical insulation system

The New Zealand Standards authority has no current vibration standards relating to human exposure since withdrawing its adoption of the ISO 2631 series in 2005. Notwithstanding this, ISO 2631-2:1989 continues to be implemented by local government and other requiring authorities. This paper conducts a review of the major environmental vibration standards (i.e. human exposure and building damage) currently in use around the world, with a view to recommending a fresh suite of standards for adoption in New Zealand. The rating systems of a selection of human response standards are compared and used in a practical study of truck vibration.

Effective strategies for the prevention of noise induced hearing loss have occupied researchers, OHS practitioners and enforcement agencies for many years. This paper reports on the second part of a major study on the epidemiology and prevention of NIHL in New Zealand. The objective of the project was to evaluate existing work-related interventions to reduce NIHL, to identify critical factors in the development and implementation of such strategies, and to propose strategies/interventions where current interventions are considered ineffective. In addition, the research examined those aspects of workplace culture that affect decision-making around NIHL. A systematic review of the research literature was completed specifically focussing on the effectiveness of interventions in the prevention of NIHL and five key strategies were identified. Data collection methodologies were developed for specific industry sectors which were segregated into high, medium and low sectors of risk of NIHL. In addition to area noise measurements and personal dosimetry, assessments of the organisation’s conformance to current noise management standards and safety climate data were undertaken. As anticipated, area and personal noise exposures were found to vary considerably within the “high risk” (agriculture, manufacturing and construction; range: LAeq 8hr 80 - 90 dB), “moderate risk” (cafes and restaurants; range LAeq 8hr 60 – 75 dB) and “low risk” sectors (pre-schools; range LAeq 8hr 70 - 80 dB). Data on enterprise conformance with the Approved Code of Practice for the Management of Noise in the Workplace indicated that most enterprises surveyed did not conform to the specific requirements of the Code in relation to noise management. As a consequence of the research, a comprehensive multi level intervention strategy is proposed.

In modern building construction, where light weight structures are preferred for cost reasons, the sound transmission is often a problem to be considered carefully, hence the many studies addressing this issue. A common floor construction in a lightweight building system is using chipboard plates attached to wooden beams by screws and glue. One drawback with such a system is the propagation of vibrations stemming either from harmonic excitation like surround systems especially at low frequencies and/or transient excitation like human walking. In order to accurately predict the sound attenuation and the losses of such building systems, computationally accurate and efficient simulation techniques are needed. The main objective of the present work is to examine sandwiched floor constructs consisting of one and two layers of chipboards attached to supporting wooden beams. Discontinuities between adjacent boards and between boards and beams are of special interest. On one hand, they affect the kinetic energy loss, due to the acoustic attenuation of evanescent waves in the structure. On the other hand, they also alter the phase shift of the waves as they travel past the different types of discontinuities in the floor assembly. A series of measurements have been performed using two-axis accelerometers distributed over the floor and recorded synchronously. A special focus has been put on investigating the low frequency range (10-600Hz), including transient loads.

Potential impacts from operational noise produced by wind turbines is a major issue during the project planning and permitting process, particularly for projects east of the Mississippi River in fairly populous areas. While still an issue farther west, more buffer space and lower population densities sometimes make noise less of a factor. In general, however, noise may be the principal obstacle, from an environmental impact standpoint, to the more rapid growth of this renewable energy source in the United States. Proposed projects are frequently opposed on noise concerns, if not outright fear, usually aroused by the highly biased misinformation found on numerous anti-wind websites. While significant noise problems have certainly been experienced at some newly operational projects, they are usually attributable to poor design (siting units too close to houses without any real awareness of the likely impact) or to unexpected mechanical noises, such as chattering yaw brakes or noisy ventilation fans. A common theme at sites with legitimate complaints is that no one - not the developer, their consultants or the regulatory authority – really understood the import and meaning of the sound levels predicted at adjacent homes in the EIS noise modeling. This paper seeks to address this lack of knowledge with suggested design goals and regulatory limits for new wind projects based on experience with the design of nearly 60 large wind projects and field testing at a number of completed installations where the apparent reaction of the community can be compared to model predictions and measurements at complainant’s homes.

We should all be proud pedants when it comes to our choice of words. Words are the primary medium through which your ideas and opinions can be conveyed. Words mean what they say, and if you want to say what you mean, then you must choose your words with great care. With that in mind, how many times have you somewhat aimlessly written or thought “the effects will be no more than minor” or “the effects are de minimis”? Be honest. It happens. A lot. These phrases have become somewhat of a mantra, trotted out automatically without a great deal of thought being given to exactly what is meant in any particular situation, or any thought being given to whether it is appropriate to use this phraseology at all. As a result, the Court still finds it necessary to remind experts and lawyers that the “no more than minor” assessment is solely a threshold test for otherwise noncomplying activities under a district or regional plan.

Augmented audio reality (AAR) is a mixture of virtual reality and the natural environment. AAR enhances the acoustics of a real world environment with additional audio information. A hearing aid is a simple example of AAR. We describe an experiment in an indoor environment with up to 16 simultaneous voices (such as in a crowded room) and up to 48 microphones in arbitrary configurations. We develop array signal processing algorithms to train the system, and separate, localize, track, enhance and zoom in on the voices. Effective audio zoom algorithms and natural gesture control will be useful in many contexts in of themselves. Their combination will enable a “super” hearing aid which can be applied to restore impaired hearing, guide visually impaired people, as well as enhance natural hearing. The longer-term objective is to develop algorithms to control the location on which the array is focused using head and eye gestures. The listener can simply look at the location from where s/he wants to hear the audio, thus controlling the audio zoom via head and eye gestures.

A comprehensive study has investigated the sound exposure that children and teachers receive in childcare centres. A small extra study investigated the hearing acuity of teachers. Personal sound exposures were measured on 73 teachers in early childhood education centres and compared to the prescribed levels for workers in the health and safety in employment legislation. Twenty eight teachers in part-time (sessional) centres and 45 teachers in all day centres were tested over one or more working days. One staff member of a sessional centre and five of those in all day centres received noise exposures well in excess of the 100% maximum daily sound exposure permitted in the workplace. Standard hearing tests were conducted on a small group of 20 teachers including young adult workers and those nearing their retirement. There was a noticeable increase in hearing loss as age increased with significant loss evident in the older participants. Reverberation times were measured in 30 early childhood learning spaces with most of the centres exceeding the 0.4 - 0.6 seconds prescribed by the Australian and New Zealand standard for classrooms and learning spaces.

The Directive 2002/49/EC requires that Action Plans for agglomeration should aim to protect quiet areas too: they have to be identified not only in open country, but also in an urban context. However, there is not yet an international agreement and a robust method to perform this identification; many approaches have been proposed from the non-acoustic one (distance from major sources of noise, public accessibility; function as a recreational space; population density; presence of sensitive buildings) to the mixed one, in which a maximum sound level is also fixed (L < 55 dB(A) in an area greater than 4.5 ha). The importance of quiet areas will increase with the second step of the Directive implementation that will regard cities with more than 100,000 inhabitants (more than 1,000 cities in Europe): large parks are not common, so it could be convenient to determine small areas where people could relax without spending too much time to reach a quiet extra-urban location. In this paper a method to determine possible “neighbourhood quiet areas” has been tested in the city of Pisa (Italy) belonging to the second step. Road traffic noise has been recognized as the principal annoying source, therefore, areas with road noise L < 55 dB(A) have been identified and selected with a GIS techniques based on land use (parks, green historical and sensitive areas) and dimensional day criteria. A post-process selection has been performed taking into account also the other noise sources in order to allow decision makers to evaluate resources availability and to develop specific Action Plans.

A common building product used in industrial buildings consists of thin steel or aluminium skins on each side of a foam plastic core such as polystyrene. Such panels have many attractive properties, they are light weight, have excellent capacity to span between structural supports, excellent thermal insulation and are pre-finished. They are used extensively in many countries, and in New Zealand these types of panels are commonly used in food processing plants which are often noisy and located close to residences. The sound transmission loss of these panels in their basic form is poor, usually less worse than a simple mass law prediction based on the mass of the components. The performance is characterised by a sharp dip in the sound transmission loss at mid frequencies which causes a big drop in R or STC rating. The work described in this paper has developed simple methods of predicting the sound transmission loss of panels both as single panels and more importantly when used as part of a system to achieve higher performance.