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Environmental Acoustics

Environmental Acoustics

Community noise is an environmental problem in our modern society. The best way to diminish this nuisance is through good planning, noise minimisation, and taking account of people's reactions to noise. SINTEF is developing tools for predicting noise levels from most community noise sources. Our main goal is the development of prediction tools for use in noise planning and noise monitoring.

MONITORING SYSTEMS

In many contexts, it is necessary to monitor the noise situation in an area. This may be required to comply with demands to report the noise emission of an enterprise, or it may be a means to influence an enterprise to achieve a beneficial effect on the surrounding environment. Sometimes only short time monitoring is required, while in other cases permanent monitoring is necessary.

SINTEF ICT has a long experience with constructing and drifting of noise measurement systems. Our experience covers the range from single sampling tests of industry enterprises, to larger, permanent noise measurement systems for airports and military activities.

Our competence includes the whole chain from basic measurement methods, choice and construction of sensor and analysis instruments, to development of computer systems for post processing and reporting.

We also develop systems for automatic recognition and classification of noise sources, and computer programs for calculation of the noise situation in larger areas which cannot be covered by a small number of measurement points.

Contact: Herold Olsen  

NOISE EFFECT STUDIES

Despite human differences, the expected reaction to a given noise level is well known. Except for noise at the workplace, which in some cases can cause hearing damage, the reactions to noise generally are nuisance and annoyance. There is also a small possibility that noise may increase the risk for cardiovascular diseases. Noise at night may cause awakening or reduced quality of sleep. Knowledge of the relation between noise exposure and reactions enable us to accurately predict the effect of various measures.

Contact: Truls T Gjestland

NOISE MITIGATION PROGRAMS

 

Due to increased activity in the society, especially in the transportation field, the outdoor noise level in communities and cities may increase gradually. The greatest noise contributer is road traffic. A reduction in noise (or rather in noise nuisance) requires several means and systematic work over time.

SINTEF ICT contribute to this by ideas, investigations, and carrying out programs. This includes, e.g.:

  • Development of basis for experienced noise nuisance, and nuisance exposure. This is a reality description and exposure estimation which is necessary to evaluate status and the effect of various measures. The work is related to the governmental action plan against noise, "Nasjonale støymål".
  • A reduction of tyre/road surface noise for cars is an important point of attack to reduce road traffic noise. This area is focused on in the Directorate of Public Roads program "environmentally friendly road surfaces". SINTEF ICT has participated in the process of establishing the program, and will work on projects related to the program withing fields such as noise measurements, relation between noise and road surface texture, evaluation and examination of measures.

SOUND PROPAGATION MODELS

 

Modelling of outdoor sound propagation is an important part of control noise calculations in relation to regulations and area development plans.

Generally, the sound propagation is dependent on topography, soil characteristics, vegetation and meteorology. We were a key player in the development of the Nordic propagation model Nord2000. This is a pioneering model that includes various propagation effects derived from exact model solutions. The work was continued in the EU project Harmonoise. We participated in the development of the Harmonoise engineering method intended for noise mapping in the EU according to the European Noise Directive 2002/49/EC.

Ray tracing is an important ingredient in these models, and also in models for sound and noise propagation underwater. We use related ray tracing models for simulating seismics, underwater communication, and underwater noise mapping.

Further development is focused on propagation of low frequency sound and vibration which is important for many noise sources. The established basis is used in Norwegian tools for noise survey and prediction.

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PREDICTION TOOLS

To describe the noise conditions in larger areas, noise calculation software is usually required to calculate a noise map. The calculation may be based on real or assumed activity. The noise maps are used, e.g. by governmental authorities in relation to area development plan, or in planning existing or future activities such as road, railway, airports and industry.

SINTEF ICT has for several decades worked with development of calculation models and computer software for the production of noise maps. Examples of such software is NORTIM for calculation of noise in the vicinity of airports, and Milstøy for calculation of noise from military activities.

SINTEF ICT participates in standardization of aircraft noise models through ANCAT/AIRMOD. NORTIM is compliant with ECAC Doc29 3rd edition, and has been part of the benchmark test to form a framework for validation of other programs using this standard.

Contact: Herold Olsen

SOURCE CHARACTERISATION

Noise reduction at the source are in most cases the technically and economically best solution to noise nuisance. An example is road traffic noise. Usually, measures such as noise screens and facade changes are implementet to reduce traffic noise. These are relatively expensive measures, which also have proven to have limited effect on traffic noise nuisance. SINTEF ICT are working on methods and technicques to characterize noise sources, both theoretically and through measurements.

In particular, work is going on to analyse road surfaces with regard to noise, and to measure tyres to examine the noise reduction potential at the source.

SINTEF ICT also participates in various international committees (e.g. ISO, ECE/GRB) which are working on improved measurement methods, and limits on noise emission from tyres and vehicles, which is intended to reduce the noise at the source.

Contact: Truls Svenn Berge