Day/Night Noise Level Electronic Assessment Tool

Providing Feedback & Corrections After using the DNL Assessment Tool, following the directions in the User's Guide, users are encouraged to provide feedback on how the DNL Assessment Tool may be improved. Users are also encouraged to send comments or corrections for the improvement of the tool. Please send comments or other input to: ATEC@hud.gov Related Information   Day/Night Noise Level Assessment Tool User Guide   Day/Night Noise Level Assessment Tool Flowcharts System Requirements   Internet Explorer 6.0 or above   Adobe Reader   Enabling JavaScript

The Environmental Planning Division has developed an electronic assessment tool that calculates the Day/Night Noise Level (DNL) from roadway and railway traffic. This is a web-based application of the existing Noise Assessment Guidelines (NAG). It is a component of the Assessment Tools for Environmental Compliance (ATEC). Derivations of the basic noise equation from the noise regulation, 24 CFR Part 51 Subpart B, were applied to a new application of the NAG.

Noise from aircraft and loud impulse sounds are not addressed through this tool. Aircraft noise data are available from the neighboring airports. Loud impulse sounds should be evaluated through the source of the noise to determine their impact and HUD’s response.

Site Acceptability Standards:

1. Exterior noise levels – Proposed HUD-assisted projects with a day-night average sound level of below 65 decibels are acceptable (see Standards in 24 CFR Part 51.103).
2. Interior noise levels – Proposed HUD-assisted projects with a day-night average sound level of below 45 decibels are acceptable.

Additional guidance on how to calculate the DNL for a proposed HUD-assisted project is available in the Department’s guidebook “The Noise Guidebook” and the regulation 24 CFR Part 51 Subpart B, Noise Abatement and Control.

To use the DNL calculator, click on the following link: DNL Calculator