Industrial Noise Pollution: Environmental and QHSE Impact

Industrial noise can affect the health and safety of workers, as well as the quality of life for local residents and the soundscape. Its prevention is based on the assessment of emissions, noise reduction at the source, and the implementation of suitable technical and organizational measures. Regulatory obligations and applicable limit values must be verified according to the country, the type of installation, and the applicable regulations.

Industrial noise pollution is not limited to the noise experienced by workers; it can also affect the soundscape and the quality of life for residents. Its prevention is part of a QHSE (Quality, Health, Safety, Environment) approach.

Distinction between the two types of noise

• Occupational noise: Assessed according to occupational exposure levels and applicable regulatory provisions. The values of 80 and 85 dB(A) correspond to action levels in certain regulatory frameworks; they should not be presented as universal exposure limit values. Prevention aims to protect the hearing and health of workers.
• Environmental noise: Concerns local residents and the effects of noise on living environments. Its assessment depends on the context, the characteristics of the noise, and the rules applicable in the country in question. The French regime for classified facilities for the protection of the environment (ICPE) should not be presented as the Moroccan regulation.

Regulation — Noise Emergence

Noise emergence corresponds to the difference between a noise level measured in a given situation and the residual noise level measured under comparable conditions, when the source under study does not contribute to the ambient noise.

Limit values for emergence depend on the applicable regulatory framework, the type of installation, the location, and the measurement period. The thresholds of 5 dB(A) during the day and 3 dB(A) at night, as well as the values of 6/4 dB(A), should not be presented as general thresholds applicable in Morocco without verification of a current legal text and its scope of application.

In Morocco, Law No. 11-03 on the Protection and Enhancement of the Environment provides, in Article 47, that noises and sound vibrations likely to disturb the neighborhood or to be detrimental to human health or the environment must be limited or eliminated under the conditions laid down in the applicable texts. The Moroccan legislative framework on the environment includes several complementary texts, notably the Framework Law No. 12-90 on the Environment, Law No. 12-03 on Environmental Impact Assessments (Dahir 1-10-08 of 02/11/2010), and Law No. 49-17 on Environmental Assessment.

Law No. 12-03 on Environmental Impact Assessments provides for the assessment of the potential effects of projects on the environment, particularly on the comfort of the neighborhood. It should not be presented, on its own, as setting numerical thresholds for noise emergence.

Acoustic Measures

• Sound level meter: Choose a device suitable for the measurement objectives, the required precision, and the applicable protocol. The IEC 61672 series defines the requirements for sound level meters.
• Sound mapping: Represent the noise levels within the factory and, where relevant, in its immediate environment. The mapping can be performed in two or three dimensions according to the needs of the study.
• Propagation model: The ISO 9613-2 standard can be used to calculate the attenuation of sound during its propagation outdoors, under the conditions provided for by this method.
• Acoustic indices: LAeq is used to characterize a continuous equivalent sound level over a given period. Lden and Lnight are used in certain environmental noise assessment frameworks; their relevance depends on the objective and the reference framework selected.

Measurements must be carried out under documented conditions and interpreted in the context of the source characteristics and the applicable regulatory or technical criteria.

Reduction at the Source

Prevention generally prioritizes measures acting on the source, then on the propagation of the noise, and finally on the protection of the receiver. The choice of solutions must be adapted to the acoustic analysis.

1. Reduction at the source: Choose quieter equipment, maintain machinery, install suitable exhaust silencers, and reduce vibrations where relevant.
2. Acoustic screens: Install screens designed to limit the propagation of noise. Their effectiveness depends particularly on their geometry, position, and acoustic properties; a high density is not sufficient to guarantee their performance.
3. Acoustic enclosures: Totally or partially enclose machines in suitable housings, taking into account ventilation, maintenance, and operational needs.
4. Building insulation: Improve the acoustic insulation of walls, openings, and building elements. Solutions must be chosen according to the frequencies and noise transmission paths.
5. Distance and siting: Where possible, distance the source from occupied areas and take into account sound propagation in the site layout. The 1/d² law does not apply universally to all industrial situations; it corresponds in particular to certain free-field propagation conditions.
6. Room-absorbing treatment: Where appropriate, use absorbing materials on the ceiling or walls, or acoustic baffles, to reduce reverberation within the room. This treatment does not necessarily replace acoustic insulation to the outside.

ICPE and Regulation in Morocco

Installations classées pour la protection de l'environnement (ICPE) fall under a French regime. This designation should not be used as if it automatically designated the Moroccan legal regime.

In Morocco, Law No. 12-03 on Environmental Impact Assessments and Law No. 49-17 on Environmental Assessment are important references for projects falling within their scope. The impact study aims in particular to assess the effects of the project on the environment and the comfort of the neighborhood, and then to provide measures to eliminate, mitigate, or compensate for the negative effects.

The requirement for an impact study, the necessary authorizations, and the acoustic prescriptions must be determined based on the texts applicable to the project in question. It should not be assumed that every noisy facility falls under a "Noise" category or that a decree systematically sets the same emergence thresholds for all establishments.

Link with ISO 14001

The ISO 14001:2015 standard provides an environmental management framework that helps organizations identify their environmental aspects, determine the associated impacts, take into account their compliance obligations, and define environmental objectives suited to their context.

Noise can be identified as an environmental aspect when the organization's activities are likely to interact with the soundscape. The standard does not set a universal acoustic threshold and does not automatically impose a quantitative noise reduction objective on all organizations. Objectives and indicators must be defined based on the impacts, applicable obligations, and commitments of the organization.

Sources et références

• Maroc — Loi n° 12-03 relative aux études d'impact sur l'environnement (Dahir 1-10-08 du 11/02/2010)

• Code du travail marocain (Loi n° 65-99), Titre IV — articles 281 et suivants (principes généraux de prévention, en cohérence avec le bruit au travail — voir article #6 Bruit catégorie sante-travail) ILO NATLEX : https://natlex.ilo.org/dyn/natlex2/r/natlex/fe/details?p3_isn=67319

• ISO — ISO 1996-1:2016, Acoustique : description, mesurage et évaluation du bruit de l'environnement, Partie 1 : grandeurs fondamentales et méthodes d'évaluation : https://www.iso.org/standard/59765.html