Environmental Prescreening Training

Federal AviationAdministrationEnvironmental

Prescreening TrainingModule 3

Noise Review

2Federal AviationAdministration

Noise Review June 25, 2013

Training Modules1. NEPA and CEQ

2. FAA Order 1050

3. Air Traffic Environmental – Noise Review

4. Environmental Screening Process Overview



Module 3

Air Traffic Environmental – Noise Review



Guidance “Significant” Impacts - Noise• Quantification of noise impacts

DNL Noise Exposure with

Proposed Action

Minimum Increase in DNL with Proposed

ActionChange in Noise Exposure Level Reference

FAA Order 1050.1E, Apdx. A, §14.314 CFR Part 150.21(2)(d)FICON 1992

FAA Order 1050.1E, Apdx A, §14.4c FICON 1992

FAA Order 1050.1E, Apdx A, §14.5e FAA Notice 7210.36045 to 60 dB 5.0 dB

Information Disclosed When Evaluating Air

Traffic Actions

65 dB 1.5 dBExceeds Threshold of

Significance

60 to 65 dB 3.0 dB

Considered When Evaluating Air Traffic

Actions



Introduction

• Noise– What is noise?– Metrics used

• Impact Categories– What categories are examined for potential

significant impacts?• Noise sensitive Areas

– What are these areas?– Why are they important?



Noise 101• One of the primary drivers for FAA air traffic

environmental studies is the potential impact of noise.– Noise is defined as the presence of unwanted

sounds– The basic unit is decibel (dB)– Noise measurements are logarithmic in nature– Most day-to-day sounds are between 30 and 100

dB.• Normal conversation at 3 feet is about 65 dB• An increase from 6dB to 10dB can be perceived as

doubling loudness



Noise 101 (Cont.)

Typical Range of Outdoor Community Day-Night Average Sound Levels



Noise 101 (Cont.)

• Several metrics are used to measure and express noise levels.– DNL: which is Day-Night Average Sound Level and

is the most commonly used metrics. – Lmax: which is the Maximum A-Weighted Sound

level– SEL: which is Sound Exposure Level or Single

Event Noise Exposure Level.– Leq: which is Equivalent Sound Level– CNEL: Community Noise Equivalent Level. Only

used in the state of California.



Noise 101 (Cont.)

Comparison of Different Sounds



Noise 101 (Cont.)

Relationship among Noise Metrics



Noise 101 (Cont.)



Noise 101 (Cont.)

Levels for which speech intelligibility is impacted



Noise 101 (Cont.)

Addition of Two Decibel Levels



Noise 101 (Cont.)

Examples of Sound Level Averaging



Noise 101 (Cont.)

Percentage of Population Highly Annoyed by General Transportation Noise



Noise Sensitive Areas and Significance

• An area where noise interferes with normal activities associated with its use.

• E.g.:• Residential• Specified areas within national parks• National wildlife refuges• Schools• Places of worship• Cultural and Historical sites



Noise Sensitive Areas and Significance (Cont.)

• Noise from airplanes and helicopters, noise sensitive areas include such areas within the Day Night Level (DNL) 65 noise contour.

• An impact on noise levels of noise-sensitive areas is considered an extraordinary circumstance and requires additional environmental analysis.



How Can We Identify Noise Sensitive Areas?• Check various sources: (e.g., airnav.com)• Check with local Airports District Office (ADO)



How Can We Identify Noise Sensitive Areas? (Cont.)



Impact Categories (Cont.)

Take a few minutes to refresh on Noise section in 1050.1E




Noise• For aviation noise analysis, the FAA has determined

that cumulative noise exposure to individuals resulting from aviation activities must be expressed in terms of annual day/night average sound level (DNL)

• If significant noise impacts are expected, then detailed noise analyses must be performed.




Noise• A significant noise impact would occur if analysis shows

that the proposed action will cause noise sensitive areas to experience an increase in noise of DNL 1.5 dB or more at or above DNL 65 dB noise exposure when compared to the no action alternative for the same timeframe.



• Quantification of noise impacts

Guidance “Significant” Impacts - Noise

DNL Noise Exposure with

Proposed Action

Minimum Increase in DNL with Proposed

ActionChange in Noise Exposure Level Reference

FAA Order 1050.1E, Apdx. A, §14.314 CFR Part 150.21(2)(d)FICON 1992

FAA Order 1050.1E, Apdx A, §14.4c FICON 1992

FAA Order 1050.1E, Apdx A, §14.5e FAA Notice 7210.36045 to 60 dB 5.0 dB

Information Disclosed When Evaluating Air

Traffic Actions

65 dB 1.5 dBExceeds Threshold of

Significance

60 to 65 dB 3.0 dB

Considered When Evaluating Air Traffic

Actions



Questions?

Environmental Prescreening Training

Documents

noise metrics

noise impacts

express noise

noise sensitive areaswhat

potential impact of

general transportation

significance cont

sound exposure level