Industrial Facilities
Site approvals for industrial facilities may require assessments of environmental noise impacts be performed in accord with state conservation department regulations and local community noise regulations. The assessments may reference maximum noise level limits specified by the agencies for boundaries with sensitive receptors or may be based on measurable background noise levels at times coinciding with site operations.
Assessments of industrial facility noise evaluate noise emissions from mobile equipment, outdoor equipment, and indoor equipment. The indoor equipment sources can include components of mechanical process noise that are propagated through building exterior constructions, ventilation openings, access doors, and equipment ducted exhaust openings. Evaluations of facility noise may also identify noise emissions from building ventilation equipment, emergency generators, and site traffic.
Noise emissions from facilities are evaluated in accord with state and local environmental noise assessment criteria using computer noise modeling programs. Inputs to the model include site development plans, manufacturer rated equipment noise levels, published reference source data, measured equipment noise levels, and measured community background noise levels.
Should site noise assessments determine that the applied criteria may be exceeded, mitigation assessments are performed to evaluate the sound attenuation effects of modifications to site layouts and development progressions, site boundary screening, and source mitigations such as source enclosure, lagging, and exhaust silencing.
Exposures of employees to indoor noise sources and to noise within equipment cabs can be evaluated in accord with Federal OSHA and MSHA employee safety requirements. Permissible noise exposure levels are specified in Federal 29 CFR Part 1910.95 Occupational Safety and Health Standards, 29 CFR Part 1926.52 Safety and Health Regulations for Construction, and 30 CFR Part 62 Occupational Noise Exposure for mine employees. For noise exposures above the permissible level, evaluations of engineering noise controls can include reviews of machine selections and investigations of installed machine or employee enclosures, partial screening, acoustic enclosure linings, and silencing.
