Environmental acoustic study: issues and methods

Definition and scope of environmental acoustics

Environmental acoustics covers all approaches to analyzing, measuring and modeling the noise levels emitted by an installation, infrastructure or human activity. The aim is to quantify the impact of these emissions on the surrounding population and environment, and then to identify solutions for bringing these levels within regulatory limits.

This discipline applies to a wide range of situations. In the design phase, a noise impact study enables us to anticipate nuisances before a plant is commissioned. In the operating phase, on-site acoustic measurements enable us to check compliance on an ongoing basis and detect any deviation from prescribed thresholds. In the event of proven non-compliance, the study provides the technical basis for designing corrective solutions.

Sectors concerned: construction and industry

Building acoustics

In the construction sector,building acoustics cover a very broad spectrum of issues. Collective housing is subject to the New Acoustic Regulations (NRA) and, for new buildings, to the requirements of the RE2020. Educational establishments, health care facilities, offices and hotels are subject to specific regulations covering insulation against airborne noise and impact noise, noise levels from technical equipment – ventilation, air conditioning, elevators – and the internal acoustic quality of spaces.

Preliminaryacoustic studies enable architects and project managers to correctly dimensionsoundproofing solutions right from the design phase, avoiding the extra costs associated with rework during construction. Acoustic impact studies in the vicinity of the building complete the system, by checking that the building does not aggravate noise levels perceived in neighboring areas.

Industrial acoustics

Industrial sites – factories, logistics warehouses, unloading platforms, production workshops – generate noise levels likely to affect local residents and workers.Industrial acoustics uses specific methodologies to characterize these sources, taking into account the nature of the equipment, production cycles and daytime and night-time operating conditions.

Construction site monitoring is another important aspect of industrial environmental acoustics. Continuous acoustic monitoring ensures that emissions remain within regulatory thresholds throughout the construction phase, which is particularly critical for sites located in dense urban areas or near sensitive zones.

ICPE acoustic measurements: regulatory framework and procedure

Installations Classées pour la Protection de l’Environnement (ICPE) are subject to precise acoustic regulations, defined by the decree of January 23, 1997 and framed by standard NF S 31-010 for the characterization and measurement of environmental noise. These texts set emission limit values at the property boundary and maximum permissible emergence levels in regulated emergence zones (ZER).

Acoustic measurement campaigns are carried out using approved and certified Class I sound level meters, guaranteeing readings that comply with normative requirements. Measurements are taken in terms of average sound levels LAeq dB(A) and frequency bands, from 125 to 4,000 Hz minimum, in order to cover the entire relevant spectrum. They are carried out during the day and at night, according to the site’s activity cycles, and postponed in the event of unfavorable weather conditions likely to affect the quality of the readings.

Measurement points are selected in consultation with the plant’s QHSE department: at the property boundary, at the source of the noisiest equipment, and in nearby ZERs. Data analysis results in an acoustic report which identifies any non-conformities, prioritizes noise sources in order of contribution, and proposes corrective technical solutions adapted to production constraints.

Simulation and topographic modeling

For industrial projects subject to authorization or appraisal by the DREAL, acoustic simulation using topographical modeling is an essential regulatory deliverable. This involves integrating topographical data on the site and its environment into certified simulation software, then incorporating the acoustic characteristics of each source: sound power, directivity, height and operating conditions.

Simulations are carried out before and after development, incorporating noise-reducing devices such as acoustic screens, enclosures and absorbent pavements. The results are presented in the form of isophonic maps and three-dimensional visuals, showing sound propagation and the effectiveness of the chosen solutions. These elements form the core of the noise impact file submitted to the administrative authorities.

The acoustic engineering firm’s approach

SIM Engineering conducts itsenvironmental acoustic studies using a multi-phase approach. The first phase is based on a site survey and an analysis of the applicable regulatory constraints, enabling us to define the most representative measurement points and the protocol best suited to the specifics of the project.

The field phase involves the use of certified Class I acoustic measuring equipment. The data collected is processed and analyzed using specialized software, then compared with current regulatory targets. When non-conformities are detected, the design office undertakes a complementary phase of measurements at source to prioritize the contributing equipment and accurately size the corrective solutions.

At the end of each project, SIM Engineering delivers a complete documentation package, including measurement results, spectral analysis, source identification and prioritization, preliminary design diagrams, estimated budget for the works, and guarantees of noise reduction prior to intervention. This level of detail ensures the project owner’s decision-making process is secure, and facilitates the examination of regulatory dossiers.

Conclusion

An environmental acoustic study is a technical prerequisite for any industrial or construction project subject to regulatory noise constraints. Field measurements, numerical simulation and standardized analysis form an indissociable triptych for demonstrating compliance and sizing effective solutions. SIM Engineering, an acoustics consultancy, supports manufacturers, local authorities and project owners at every stage of their projects. For all yourenvironmental acoustics needs, contact SIM Engineering for an analysis tailored to your situation.