Malibu Municipal Code § 6.2 Standards, Plans and Regulations

Noise has the potential to affect human health in various ways. Community decision makers may use available community noise information, therefore, to ensure that a minimum number of people are exposed to potentially harmful noise sources. To aid decision makers, several federal and state agencies have established noise/land use compatibility guidelines. These guidelines are all based upon cumulative noise criteria, such as Leq, CNEL, or Ldn. These land uses and compatibility guidelines are illustrated in Figure N-2.

In March 1984, the EPA published a document which for the past nine years has served as the primary source of information about noise and its effects on land use and people. The document entitled Information of Levels of Environmental Noise Requisite to Protect Public Health and Welfare With an Adequate Margin of Safety (EPA 550/9-74-004), contains a table which identifies indoor thresholds requisite for protecting human health in both indoor and outdoor environments.

According to this publication, 55 Ldn is described as the threshold level with an adequate margin of safety for areas for outdoor activities associated with residential development and recreational activities. The document and the thresholds are not considered standards, specifications, or regulations.

The FHWA has adopted and published noise abatement criteria for highway construction projects. The FHWA abatement criteria establishes an exterior noise goal for residential land uses of 67 Leq. The interior goal for residences is 52 Leq. The criteria apply to private yard areas and assume that typical wood frame houses with open windows provide a 10 dB noise reduction and a 20 dB noise reduction with the windows closed.

The State of California has adopted noise standards in areas of regulation not preempted by the federal government[1]. State standards regulate noise levels of motor vehicles, freeway noise affecting classrooms, sound transmissions, occupational noise control, and airport noise. The purpose of the standards is to establish minimum noise insulation performance standards to protect persons within new hotel, motels, apartment houses, and dwellings other than detached single-family dwellings. The standards specify that interior noise levels, with windows closed, attributable to exterior sources shall not exceed an annual noise level of 45 dB CNEL in any habitable room. In addition, residential buildings or structures within a 60 dB CNEL exterior noise environment due to airport, vehicular, or industrial noise sources are required to have an acoustical analysis prepared indicating that the proposed building has been designed to limit intruding noise to the allowable 45 dB CNEL interior noise level.

In 1976, the Department of Health, State Office of Noise Control published a recommended noise/land use compatibility matrix which many jurisdictions have adopted as a standard in their general plan noise elements. This matrix indicates that residential land uses and other noise sensitive receptors generally should locate in areas where outdoor ambient noise levels do not exceed 65 to 70 dBA (CNEL or Ldn).

[1]

The California Sound Transmission Control Standards are found in California Administrative Code, Title 25, Building Standards, Chapter 2.5, as adopted March 1, 1986.