August Mack Newsletter | July, 2017

HUD Noise Assessments
by Rose Fortman

Housing projects receiving federal assistance, subsidy, or insurance through the U.S. Department of Housing and Urban Development (HUD) are required to comply with a host of federal regulations, including the Noise Abatement and Control requirements under 24 CFR Part 51 Subpart B. HUD’s goal is to generally protect citizens against excessive noise in their communities and places of residence.

Day-night Average Sound Level (DNL)

The protocol for evaluating noise is to conduct a HUD Noise Assessment in accordance with the HUD Noise Assessment Guidelines. Noise Assessments involve calculating the day-night average sound level (DNL) based on the accumulation of noise from all noise-producing sources in the vicinity of the project site. The DNL is a metric, measured in decibels (dB), with a weighted concentration for night time noise, the time at which residents are most sensitive to noise.

Noise Sources

Potential noise sources that must be evaluated:

  • Major roadways with 1,000-feet
  • Railroads within 3,000-feet
  • Civil airports within 5 miles
  • Military airfields within 15 miles

Once sources are identified, data related to average daily operations and traffic counts are obtained from public sources. Details such as average speeds, number of train cars/heavy trucks, as well as specific consideration for night time operations and future projections within a 10-year timeframe are incorporated.  

Results of the Noise Assessment

Based on the data collected, and the distance of the sources from the Site, the DNL for the site is determined using the DNL Electronic Assessment Tool/DNL Calculator. The resulting site DNL value will fall into one of three categories:

HUD Noise Category

Day-night average sound level (DNL)


65 dB or below

Normally Unacceptable

65 dB to 75 dB


Above 75 dB

If the project is within the Acceptable range, it is in compliance. If the project is in the Normally Unacceptable range, additional noise attenuation measures are required for new construction and strongly encouraged for major rehabilitation projects. Attenuation may include the use of barriers, adjusting the layout of the project, or use of building materials to result in a HUD acceptable interior noise level of 45 decibels. If the project is in the Unacceptable range, new construction of noise sensitive uses is generally prohibited. Attenuation measures may be submitted to the Assistant Secretary for Community Planning and Development (CPD) or the Responsible Entity’s Certifying Officer for approval on a case-by-case basis. An Environmental Impact Statement (EIS) is also normally required in this case. 

To learn more about this topic, register to attend our free webinar, HUD Noise Assessments, on September 27, 2017 @ 3:00pm.

Rose Fortman is a Senior Technical Report Writer and Staff Geologist for August Mack Environmental, Inc. in the Ohio office and has more than ten years of experience in environmental consulting. She has spent much of her consulting career conducting Transaction Activities including Phase I Environmental Site Assessments (ESAs), Record Search with Risk Assessments, and Phase II Subsurface Investigations. She has also worked in conjunction with state agencies and developers on HUD Environmental Assessments and environmental aspects of affordable housing projects. Rose can be reached at 740.548.1515 or via e-mail at

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