TABLE 3
|
|
Ldn Value |
|
|
Land Use Category |
Clearly Acceptable |
Normally Acceptable |
Normally Unacceptable |
Clearly Unacceptable |
|
|
|
|
|
Residential: single family, duplex, mobile home |
Ldn < 60 |
60 < Ldn < 65 |
65 < Ldn < 75 |
Ldn > 75 |
Residential: multi-family, dormitories |
Ldn < 60 |
60 < Ldn < 65 |
65 < Ldn < 75 |
Ldn > 75 |
Transient Lodging |
Ldn < 65 |
65 < Ldn < 70 |
70 < Ldn < 80 |
Ldn > 80 |
School Classrooms, Libraries, Churches |
Ldn < 60 |
60 < Ldn < 65 |
65 < Ldn < 75 |
Ldn > 75 |
Hospitals, Nursing Homes |
Ldn < 60 |
60 < Ldn < 65 |
65 < Ldn < 75 |
Ldn > 75 |
Auditoriums, Concert Halls, Music Shells |
Ldn < 50 |
50 < Ldn < 60 |
60 < Ldn < 70 |
Ldn > 70 |
Sports Arena, Outdoor Spectator Sports |
Ldn < 60 |
60 < Ldn < 65 |
65 < Ldn < 75 |
Ldn > 75 |
Playgrounds, Neighborhood Parks |
Ldn < 55 |
55 < Ldn < 65 |
65 < Ldn < 75 |
Ldn > 75 |
Golf Courses, Riding Stables, Cemeteries, Water Recreation |
Ldn < 60 |
60 < Ldn < 70 |
70 < Ldn < 80 |
Ldn > 80 |
Office Buildings: professional |
Ldn < 65 |
65 < Ldn < 75 |
75 < Ldn < 80 |
Ldn > 80 |
Commercial: retail, movie theaters, restaurants |
Ldn < 65 |
65 < Ldn < 75 |
75 < Ldn < 80 |
Ldn > 80 |
Commercial: wholesale, light manufacturing, utilities |
Ldn < 70 |
70 < Ldn < 80 |
80 < Ldn < 85 |
Ldn > 85 |
Manufacturing: noise sensitive |
Ldn < 55 |
55 < Ldn < 70 |
70 < Ldn < 80 |
Ldn > 80 |
Livestock Farming, Animal Breeding |
Ldn < 60 |
60 < Ldn < 75 |
75 < Ldn < 80 |
Ldn > 80 |
Agriculture (not livestock), Mining, Fishing |
Ldn < 75 |
75 < Ldn < 95 |
|
|
Public right-of-way |
Ldn < 75 |
75 < Ldn < 85 |
85 < Ldn < 95 |
|
Extensive Natural Recreation Areas |
Ldn < 60 |
60 < Ldn < 75 |
75 < Ldn < 85 |
Ldn > 85 |
Source: The Noise
TABLE 4
EPA Cause-And-Effect Relationships
Type of Comparison |
Land Use |
“Cause” |
“Effect[1]” |
|
|
|
|
Absolute comparison (Based on overall magnitude of the sound level) |
Residences Hospitals |
55 dBA Ldn (OUTDOORS) |
IMPACT THRESHOLD[2] 1. 95% sentence intelligibility (average) at 3.5m (11 ft.), normal voice 2. Indoors, 100% sentence intelligibility with a 5 dB margin of safety, normal voice[3] 3. Consistent with available sleep criteria |
|
|
65 dBA Ldn (OUTDOORS) |
1. 95% sentence intelligibility (average) at 1m (3 ft.), normal voice 2. Indoors, greater than 99% sentence intelligibility, normal voice3 3. Above available sleep criteria |
|
|
75 dBA Ldn (OUTDOORS) |
1. 95% sentence intelligibility (average) at 0.7m (2ft), raised voice: or at 1.5m (5ft), loud voice 2. Indoors, greater than 95% sentence intelligibility, normal voice3 3. Further above available sleep criteria |
|
Educational Uses |
55 dBA Leq (24) (OUTDOORS) |
IMPACT THRESHOLD outdoors IMPACT THRESHOLD, with 5 dB margin of safety, indoors3 |
Relative comparison[4] (Based on the difference between existing and project induced sound levels) |
Residences |
Intruding noise 5 dBA less than background noise, in the absence of the intruding noise |
IMPACT THRESHOLD 1. 15% complaints 2. 15-20% highly annoyed 3. Noise essentially least important of various community factors 4. No expected community reaction |
|
|
Intruding noise exceeds background by 5 dBA |
1. 5% complaints 2. 30-35% highly annoyed 3. Threats of legal action |
|
|
Intruding noise exceeds background by 15 dBA |
1. 15% complaints 2. 50-55% highly annoyed 3. Vigorous community action expected |
[1] All percentages shown are average percentages; specific percentage values depend upon community attitudes towards the noise source, prior experience with similar noise sources, plus other factors not related to the actual noise level.
[2] “Requisite to protect the public health and welfare with an adequate margin of safety.”
[3] Windows assumed open, resulting in outdoor-to-indoor noise insulation of 15 dBA.
[4] This presentation of EPA conclusions condenses the EPA’s “normalized Ldn,,” to a single IMPACT THRESHOLD tabulation. This condensation is consistent with the following average background noise levels:
and from industrial activity and trucking)
traveled roads and industrial areas)
roads or industrial areas)
Source: U.S. Environmental Protection Agency, “Information on Levels of Environmental Noise Requisite to Protect Public Health and Welfare with an Adequate Margin of Safety,” Report 550/9-74-004, Washington, D.C., March 1974.