9.6.8 Noise Abatement and Control (24 CFR Part 51, Subpart B)

A. HUD standards regarding the acceptability of noise impacts on residential property are found at 24 CFR Part 51 Subpart B. The noise regulation applies to all projects as noted below except those categorically excluded (CENST) under 24 CFR 50.19 (see Section 9.1.3.C.1 and Section 9.1.3.C.2.)

B. For new construction and conversions from non-residential to residential located above the noise threshold criteria, projects shall incorporate noise attenuation features as required by HUD environmental criteria and standards at 24 CFR 51.104. The interior standard is 45 dB (decibels).

C. The "Normally Unacceptable" noise zone includes community noise levels from above 65 dB to 75 dB. Approvals in this noise zone require a minimum of 5 dB additional sound attenuation for buildings having noise-sensitive uses if the day-night average sound level is greater than 65 dB but does not exceed 70 dB, or a minimum of 10 decibels of additional sound attenuation if the day-night average sound level is greater than 70 dB but does not exceed 75 dB. Where the sound attenuation is determined using the online Sound Transmission Classification Assessment Tool (STrraCAT), the required attenuation value provided by the tool may be used (https://www.hudexchange.info/stracat/).

D. Locations with day-night average noise levels above 75 dB have “Unacceptable” noise exposure. Noise assessments must be projected out 10 years.

54 See 24 CFR 55.28.

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E. For rehabilitation projects that require an Environmental Assessment level of review, HUD will actively seek noise mitigation for projects in the “Normally Unacceptable” or “Unacceptable” noise zones. For projects in the “Unacceptable” zone where HUD policy strongly encourages conversion of noise exposed sites to land uses compatible with the high noise levels, HUD will also critically evaluate the application to determine the project’s compatibility with HUD’s interior noise goal of a day-night average of 45 decibels, and to determine the noise level’s effect on marketability.

F. For 223(f) and other refinance or rehabilitation projects at the CEST level of review, HUD will encourage appropriate noise attenuation measures for inclusion in the project. Noise exposure by itself will not result in the rejection of existing residential properties for mortgage insurance but is a marketability factor that HUD will consider in determining if the amount of any insurance or other assistance that may be given. Projects at the CEST level of review are not required to complete a noise calculation but must complete preliminary noise screening of distance from noise sources. The preliminary screening must include distance from the project to each noise source.

G. Lenders should contact regional Multifamily staff prior to attempting to design mitigation measures.

H. New construction or conversions of existing structures to residential housing in the Unacceptable Noise Zone, where outdoor noise levels are above 75 dB, are generally prohibited. If the Regional Office wants to consider such a proposal, it must:

1. Require an Environmental Impact Statement (EIS). If the Regional Office believes that the proposal is acceptable based on the EIS, it must then obtain project approval, including approval of noise mitigation measures, from the appropriate Assistant Secretary as required in HUD’s noise regulations.

2. If the Regional Office determines that noise is the only environmental issue and no outdoor noise sensitive activity that is not mitigated to below HUD’s 65 dB standard will take place on the site, it may request a waiver of the EIS Requirement by the appropriate Assistant Secretary as required in HUD’s noise regulations and must also obtain project approval, including approval of noise mitigation measures, from that Assistant Secretary.[55]

I. Balconies[56] :

1. There are generally no restrictions on balconies for existing residential projects, although HUD encourages noise attenuation. For new construction projects or existing projects that convert from non-residential to residential in Unacceptable and Normally Unacceptable noise areas, bedrooms and studio apartments may have direct access to balconies if:

   • The interior noise levels have been mitigated to not exceed a day-night average noise level of 45 dB as documented by the Sound Transmission Classification of the dwelling unit’s exterior walls factoring in fenestration.

• Appropriate ventilation is provided by a mechanical ventilation system and not by opening doors or windows, and

55 Information about HUD’s EIS waiver process for sites in the Unacceptable Noise Zone can be found at https://www.hudexchange.info/programs/environmental-review/housing/#faq.

56 Notice CPD-16-19: Balcony Policy Under 24 CFR 51, Subpart B as it Applies to Parts 50 and 58 Regarding Building Facades Exposed to Noise.

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• An Operations and Maintenance plan is in place that requires periodically inspecting seals and repairing or replacing building components when their performance diminishes.

2. Bedrooms and studio apartments may not have direct access to balconies if there is no mechanical ventilation and there is no Operations and Maintenance plan requiring periodic inspection and repair or replacement of all window and door seals as needed.

3. HUD Approving Officials may require additional mitigation measures or deny approval of balconies based on noise or other concerns. In addition, Environmental Assessment or Environmental Impact Statement levels of environmental review must consider potential health effects stemming from issues related to noise sources, such as air quality (24 CFR 50.4(h)) and toxic hazard exposure near transportation (24 CFR 50.3(i)).

J. The HUD noise regulation allows flexibility for non-acoustic benefits in limited situations. The project must meet all of the conditions at 24 CFR 51.105 and receive the approval of a Regional or Field Environmental Officer.

K. Regarding Railroad Vibration, Noise, and Location:

1. Buildings closer than 100 feet to a railroad track are often subject to excessive vibration transmitted through the ground. For existing properties, the structure should be examined for damage caused by vibrations. A railroad vibration study and vibration mitigating measures may be required. These studies should be performed by a registered professional engineer with experience in structural vibration analysis.

2. Whenever rail lines are less than 100 feet from a facility, HUD approval should be obtained prior to the application submission. In addition to concerns about vibration, HUD will want documentation that the project complies with applicable LSTF safety standards.

3. Railyards (areas of multiple track sections used for assembling and disassembling trains) have been determined to create loud, impulsive sounds. For projects within 3,000 ft of actively operating rail yards, HUD may require up to 8 dB additional noise attenuation to be incorporated in the project. In determining whether this is necessary, HUD will consider the impact of existing or proposed barriers, topography, and nature of the rail yard operations.