HUD’s noise standards may be found in 24 CFR Part 51, Subpart B. For proposed new construction in high noise areas, the project must incorporate noise mitigation features. Consideration of noise applies to the acquisition of undeveloped land and existing development as well.
All sites whose environmental or community noise exposure exceeds the day night average sound level (DNL) of 65 decibels (dB) are considered noise-impacted areas. For new construction that is proposed in high noise areas, grantees shall incorporate noise attenuation features to the extent required by HUD environmental criteria and standards contained in Subpart B (Noise Abatement and Control) of 24 CFR Part 51. The interior standard is 45dB.
The "Normally Unacceptable" noise zone includes community noise levels from above 65 decibels to 75 decibels. 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.
Locations with day-night average noise levels above 75 dB have “Unacceptable” noise exposure. For new construction, noise attenuation measures in these locations require the approval of the Assistant Secretary for Community Planning and Development (for projects reviewed under Part 50) or the Responsible Entity’s Certifying Officer (for projects reviewed under Part 58). The acceptance of such locations normally requires an environmental impact statement.
In "Unacceptable" noise zones, HUD strongly encourages conversion of noise-exposed sites to land uses compatible with the high noise levels.
Are there potential noise generators in the vicinity of the project? Review general location maps and/or conduct a field review to screen for major roadways (within 1,000 feet), railroads (within 3,000 feet), and military or FAA-regulated airfields (with 15 miles) in the vicinity of the project.
If a noise assessment was performed, was the noise found to be Acceptable, Normally Unacceptable, or Unacceptable?
Site Acceptability Standards
Day-night average sound level (in decibels)
Special approvals and requirements
Above 65 dB
but not exceeding 75 dB
- Environmental assessment and attenuation required for new construction
- Attenuation strongly encouraged for major rehabilitation
Note: An environmental impact statement is required if the project site is largely undeveloped or will encourage incompatible development.
Above 75 dB
- Environmental impact statement required
- Attenuation required for new construction with approval by the Assistant Secretary of CPD or Certifying Officer
Compliance and Documentation
The environmental review record should contain one of the following:
- Documentation the proposed action is not within 1000 feet of a major roadway, 3,000 feet of a railroad, or 15 miles of a military or FAA-regulated civil airfield
- If within those distances, documentation showing the noise level is Acceptable (at or below 65 DNL)
- If within those distances, documentation showing that there’s an effective noise barrier (i.e., that provides sufficient protection)
- Documentation showing the noise generated by the noise source(s) is Normally Unacceptable (66 – 75 DNL) and identifying noise attenuation requirements that will bring the interior noise level to 45 DNL and/or exterior noise level to 65 DNL
View Noise Abatement and Control (CEST) - Worksheet.
View Noise Abatement and Control (EA) - Worksheet.
View Noise (CEST) - Partner Worksheet.
View Noise (EA) - Partner Worksheet.
- Fact Sheet: Public Art and Noise Mitigation
This fact sheet provides guidance on integrating public art into noise mitigation projects to make noise mitigation an amenity that is visually interesting and culturally relevant to the residential community.
- HUD Memo: Application of §51.104 to Land Use Conversions
This memorandum clarifies existing policy on rehabilitation of existing buildings that changes the original land use. New land uses resulting from rehabilitation may be considered new noise-sensitive uses as if they were new construction. If those new uses are in Unacceptably noise-exposed areas (external noise greater than 75 decibels), an Environmental Impact Statement is required. For more information, contact your Field or Regional Environmental Officer.
- HUD Noise Guidebook
The Noise Guidebook has been prepared to serve as the basic reference document for all who are responsible for implementing the Department's noise policy. It brings together training and guidance to complete HUD noise assessments.
- Day/Night Noise Level Electronic Assessment Tool (aka: the DNL Calculator)
The Office of Environmental and Energy has developed an electronic assessment tool that calculates the Day/Night Noise Level (DNL) site exposure. This is a web-based application of the existing Noise Assessment Guidelines (NAG). It is the basic noise assessment tool; most assessments start here. The DNL Calculator calculates noise from road and railway activity levels. It then combines the noise with airport projections and incorporates the effects of loud, impulsive sound for a site exposure at any Noise Assessment Location. The DNL Calculator can document compliance or aid in site planning. It is quick and easy to use.
- Sound Transmission Classification Assessment Tool
The Sound Transmission Classification Assessment Tool (STraCAT) is a web-based application that automates and streamlines the completion of HUD’s Figure 19 in The Noise Guidebook. That is the form that reports the noise mitigation performance of wall systems.
- Barrier Performance Module
The Barrier Performance Module (BPM) is an automated version of the noise barrier evaluation worksheets and charts in the Noise Guidebook. It reports the amount of noise to be reduced by a particular design. It is linked to the DNL Calculator. The output of the DNL Calculator is used as the input to the Barrier Performance Module, but it can also be used stand-alone.
- Fact Sheet: Recommended Environmental Review Record Documentation to Support an Environmental Impact Statement Waiver for Projects in Unacceptable Noise Conditions
This fact sheet provides the recommended environmental review record documentation to support an environmental impact statement waiver for projects in unacceptable noise conditions.
- Noise Assessment Training Webinar
This webinar, held October 19, 2011, describes basics concepts of noise related to the built environment; use of OEE’s Day/Night Noise Level Calculator and Barrier Performance Module; common errors and mistakes to avoid; and potential applications for project planning.