Goal HAZ-8: Minimize human exposure to excessive noise and ground vibration.
Exposure to excessive noise can impact the health and quality of life of residents and employees. Excessive noise can cause hearing loss, stress, hypertension, sleep disturbance, and fatigue. The Hayward community contains a variety of noise sources, including aircraft, trains, vehicle traffic on freeways and roadways, and industrial and commercial operations. This goal and its supporting policies are designed to minimize human exposure to excessive noise by evaluating noise exposure risks and incorporating appropriate mitigation measures.
The City shall strive to locate noise sensitive uses, (e.g., residences, schools, hospitals, libraries, religious institutions, and convalescent homes) away from major sources of noise.
Noise Terminology
dBA: Measurement unit for “a-weighted decibels,” which are commonly used for measuring environmental and industrial noise and the potential hearing damage associated noise health effects.
Equivalent Noise Level (Leq): Constant noise level that would deliver the same acoustic energy to the ear of a listener as the actual time-varying noise would deliver over the same exposure time. No “penalties” are added to any noise levels during the exposure time; Leq would be the same regardless of the time of day during which the noise occurs.
Day-Night Average Noise Level: (Ldn): A 24-hour average Leq with a 10dBA “penalty” added to noise levels duringthe hours of 10:00 P.M. to 7:00 A.M. toaccount for increased sensitivity that peopletend to have to nighttime noise. Becauseof this penalty, the Ldn would always behigher than its corresponding 24-hour Leq(e.g., a constant 60 dBA noise over 24hours would have a 60 dBALeq, but a66.4 dBALdn).
Community Noise Equivalent Level (CNEL):An Ldn with an additional 5 dBA “penalty” for the evening hours between 7:00 P.M. and 10:00 P.M. This is essentially a measure of ambient noise.
Sound Exposure Level or Single Event Level (SEL): A descriptor used to characterize the severity of short-duration sound events. SEL is the time-averaged, constant intensity, A-weighted sound level over a one-second reference time that would produce the same sound exposure as the actual time-varying sound over the actual exposure time. In practice,SEL is usually applied in situations where there are multiple sound events, each one having its own characteristic SEL.
The City shall require development projects in areas where they may be exposed to major noise sources (e.g. roadways, rail lines, and aircraft or other non-transportation noise sources) to conduct a project level environmental noise analysis. The noise analysis shall determine noise exposure and noise standard compatibility with respect to the noise standards identified in Table HAZ-1 and shall incorporate noise mitigation when located in noise environments that are not compatible with the proposed uses of the project. The City shall use Table HAZ-1 (Exterior Noise Standards for Various Land Uses) and Figure HAZ-1 (Future Noise Contour Maps) to determine potential noise exposure impacts, noise compatibility thresholds, and the need for mitigation. The City shall determine mitigation measures based on project-specific noise studies, and may include sound barriers, building setbacks, the use of closed windows and the installation of heating and air conditioning ventilation systems, and the installation of noise attenuating windows and wall/ceiling insulation.
The City shall consider the potential noise impacts of commercial and industrial developments that are located near residences and shall require noise mitigation measures as a condition of project approval.
The City shall consider the visual impact of noise mitigation measures and shall require solutions that do not conflict with urban design goals and standards.
The City shall require the design of new residential development to comply with the following noise standards:
· The maximum acceptable interior noise level for all new residential units (single-family, duplex, mobile home, multi-family, and mixed use units) shall be an Ldn of 45 dB with windows closed.
· For project locations that are primarily exposed to aircraft, train, and BART noise, the maximum instantaneous noise level in bedrooms shall not exceed 50dB(A) at night (10:00 pm to 7:00 am), and the maximum instantaneous noise level in all interior rooms shall not exceed 55dB(A) during the day (7:00 am to 10:00 pm) with windows closed.
· The maximum acceptable exterior noise level for the primary open space area of a detached single-family home, duplex or mobile home, which is typically the backyard or a fenced side yard, shall be an Ldn of 60 dB. This standard shall be measured at the approximate center of the primary open space area. This standard does not apply to secondary open space areas, such as front yards, balconies, stoops, and porches.
· The maximum acceptable exterior noise level for the primary open space area of townhomes and multi-family apartments or condominiums (private rear yards for townhomes; and common courtyards, roof gardens, or gathering spaces for multi-family projects) shall be an Ldn of 65 dB. This standard shall be measured at the approximate center of the primary open space area. This standard does not apply to secondary open space areas, such as front yards, balconies, stoops, and porches.
· The maximum acceptable exterior noise level for the primary open space area of urban residential infill and mixed-use projects (private rear yards for townhomes; and common courtyards, roof gardens, or gathering spaces for multi-family or mixed-use projects) shall be an Ldn of 70 dB. residential infill would include all types of residential development within existing or planned urban areas (such as Downtown, The Cannery Neighborhood, and the South Hayward BART Neighborhood) and along major corridors (such as Mission Boulevard). This standard shall be measured at the approximate center of the primary open space area. This standard does not apply to secondary open space areas, such as front yards, balconies, stoops, and porches.
The City shall require the design of new lodging facilities, nursing homes, hospitals, and other similar uses to comply with the following noise standards:
· The maximum acceptable interior noise level for sleeping areas shall be an Ldn of 45 dB with windows closed.
· For project locations that are primarily exposed to aircraft, train, and BART noise, the maximum instantaneous noise level in sleeping areas shall not exceed 50dB(A) at night (10:00 pm to 7:00 am) and 55dB(A) during the day (7:00 am to 10:00 pm) with windows closed.
The City shall require the design of new office developments and similar uses to achieve a maximum interior noise standard of 45dBA Leq (peak hour).
The City shall coordinate with the Hayward Area Recreation and Park District (HARD) and the East Bay District (EBRPD) to establish and enforce hours of operation for park and recreational facilities near residential homes.
The City shall encourage businesses to comply with Occupational Safety and Health Administration (OSHA) standards related to noise safety and ear protection when employees work in noisy environments (interior and exterior).
The City shall encourage BART and AC Transit to upgrade their trains and transit fleets with vehicles that generate less noise when driving and idling.
The City shall encourage Caltrans, in conjunction with any new freeway project, to construct attractive sound walls and landscaping strips along freeways to protect adjacent areas from excessive freeway noise.
The City shall consider potential noise impacts when evaluating proposals for transportation projects, including road, freeway, and transit projects, and will strive to minimize noise impacts through the implementation of mitigation measures.
The City shall require the evaluation of public facilities (e.g., utility substations, water storage facilities, and pumping stations) to determine potential noise impacts on surrounding uses and identify appropriate mitigation measures.
The City shall monitor noise impacts from aircraft operations at the Hayward Executive and maintain and implement the noise abatement policies and procedures outlined in the Noise Ordinance and Land Use Compatibility Plan.
The City shall require project applicants to evaluate potential airport noise impacts if the project is located within the 60 dB CNEL contour line of the Hayward Executive or Oakland International (as mapped in the Land Use Compatibility Plan). All projects shall be required to mitigate impacts to comply with the interior and exterior noise standards established by the Land Use Compatibility Plan.
The City shall require that all new development within an airport-defined over-flight zone provide deed notices disclosing airport over-flights and noise upon transfer of title to future residents and property owners.
The City shall maintain, implement, and enforce a community noise control ordinance to regulate noise levels from public and private properties, vehicles, construction sites, and landscaping activities.
The City shall require the full disclosure of the potential noise impacts of living in a mixed-use development by requiring residential disclosure notices within deeds and lease agreements as a condition of project approval.
The City shall require the full disclosure of the potential noise impacts of living in an urban downtown environment by requiring residential disclosure notices within deeds and lease agreements as a condition of project approval.
The City may require development projects subject to discretionary approval to assess potential construction noise impacts on nearby sensitive uses and to minimize impacts on those uses, to the extent feasible.
The City shall limit the hours of construction and maintenance activities to the less sensitive hours of the day (7:00am to 7:00pm Monday through Saturday and 10:00am to 6:00 pm on Sundays and holidays)
The City shall require a vibration impact assessment for proposed projects in which heavy-duty construction equipment would be used (e.g. pile driving, bulldozing) within 200 feet of an existing structure or sensitive receptor. If applicable, the City shall require all feasible mitigation measures to be implemented to ensure that no damage or disturbance to structures or sensitive receptors would occur.
The City shall require new residential and commercial projects located within 200 feet of existing major freeways and railroad lines (e.g. freight, Amtrak, and Bay Area Rapid Transit) to conduct a ground vibration and vibration noise evaluation consistent with City approved methodologies (e.g. Caltrans, Federal Transportation Authority).