HomeMy WebLinkAbout; Kelly Ranch Area E, Exterior Noise Analysis; Kelly Ranch Area E, Exterior Noise Analysis; 1996-11-19EXTERIOR NOISE ANALYSIS FOR
KELLY RANCH AREA E
CITY OF CARLSBAD
Report #96-173
November 19,1996
PreparedFor:
Hillman Properties West, Inc.
2011 Palomar Airport Road
Suite 206
Carlsbad, C A 92009
(619)931-1190
Prepared By:
"Vincent Mestre, RE.
Henry Moon
MESTRE GREVE ASSOCIATES
280 Newport Center Drive
Suite 230
Newport Beach, CA 92660-7528
(714) 760-0891
SUMMARY OF MITIGATION REQUIREMENTS FOR
KELLY RANCH AREA E
EXTERIOR REQUIREMENTS
The City of Carlsbad General Plan specifies outdoor and indoor noise limits for various land-uses.
The standard states that for residential land use, the exterior Community Noise Equivalent Level
(CNEL) shall not exceed 60 dB.
The projected unmitigated traffic noise exposure levels at the rear yards along Cannon Road will
range from 62.4 dB to 71.3 dB CNEL. Since the unmitigated noise levels at the rear yards exceed
the exterior noise standard, mitigation measures will be required.
NOISE BARRIER REQUIREMENTS TO MEET THE 60 CNEL STANDARD
A perimeter wall, 5.5 feet to 9.0 feet in height should be located along the top of slope between the
units facing Cannon Road and the roadway. Refer to Exhibit S1 for the location of the required
noise barriers. The required barriers will reduce the first floor exterior noise levels to a range of
54.6 to 59.2 dB A CNEL for the lots adjacent to Cannon Road.
The lots at the north end of the site (Lots 120, 121, and A) are also exposed to noise from traffic
along El Camino Real and will require a perimeter wall that is 6.5 to 7.0 feet high at the property
line. The pad elevation of these lots (Lots 120, 121, and A) are lower than the roadway elevation
of El Camino Real which means that a barrier located at the roadway edge would allow a lower
barrier than a barrier located at the property line. However, since only three lots along El Camino
Real need barriers, it would be more economical to place a noise barrier that is 7.0 feet tall to
surround only three lots than to have a much longer 5 foot barrier along El Camino Real. The
different barrier height locations are listed in Table S-1.
TABLE S-l
REQUIRED BARRIER HEIGHTS TO MEET THE 60 CNEL STANDARD
LOT NO. WALL HEIGHT (FT.)
Along El Camino Real
120
121
A
Along Cannon Road
121
A
122 to 123
124 to 127
128 to 129
131 to 134
Ito3
5 to 19
6.5
6.5
7.0
5.5
7.5
8.5
9.0
8.5
8.5
8.5
8.5
MGA
MESTRE GREVE ASSOCIATES
Exhibit SI
Required Noise Barrier Location (60 CNEL)
MESTRE GREVE ASSOCIATES
Exhibit S2
Required Noise Barrier Location (65 CNEL)
NOISE B ARRffiR REQUIREMENTS TO MEET THE 65 CNEL STANDARD
A perimeter wall, 5.5 feet to 6.5 feet in height should be located along the top of slope between the
units facing Cannon Road and the roadway. Refer to Exhibit S2 for the location of the required
noise barriers. The required barriers will reduce the first floor exterior noise levels to a range of
60.1 to 64.2 dBA CNEL for the lots adjacent to Cannon Road. The different barrier height
locations are listed in Table S-2.
As previously mentioned, the lots at the north end of the site (Lots 120, 121, and A) are also
exposed to noise from traffic along El Camino Real. The combined noise exposure at Lots 120,
121, and A will be 56.5, 63.7, and 63.5 dBA CNEL, respectively. Since the noise exposure at
these northern lots will be less than 65 CNEL, no barriers will be required to attenuate the traffic
noise along El Camino Real.
TABLE S-2
REQUIRED BARRIER HEIGHTS TO MEET THE 65 CNEL STANDARD
LOT NO. WALL HEIGHT (FT.)
Along El Camino Real
120 No Barrier Required
121 No Barrier Required
A No Barrier Required
Along Cannon Road
121 0.0
A 5.5
122 to 123 5.5
124 to 127 6.5
128 to 129 6.0
131 to 134 6.0
1 to 3 6.0
5 to 19 6.0
INTERIOR REQUIREMENTS
The proposed project must comply with the City's interior noise standard of 45 dB CNEL. To
comply with the interior noise standard, the proposed buildings must provide sufficient outdoor to
indoor noise attenuation to reduce the interior noise exposure down to acceptable levels. The
projected unmitigated traffic noise exposure levels at the second floor building faces will range
from 60.1 dB CNEL to 70.0 dB CNEL. This means the structure must provide from 15.1 to 25.0
dB of exterior to interior noise reduction. When the exterior to interior noise reduction exceeds 20
dB, engineering calculations should be provided to ensure compliance with the interior noise
requirement. The calculation of the noise reduction provided by the structures can be
accomplished when the final architectural plans are completed. An additional study will be
required when architectural drawings become available identifying mitigation requirements needed
to meet the interior noise standard.
MGA
NOISE ANALYSIS FOR KELLY RANCH AREAE
CITY OF CARLSBAD
1.0 INTRODUCTION
The purpose of this report is to determine compliance of Kelly Ranch AreaE with the City of
Carlsbad's exterior noise standards. The subject project is located along the south side of Cannon
Road west of El Camino Real in the City of Carlsbad. See Exhibit 1 for the location of the project
site. The project site is located approximately one mile north of McClellan Palomar Airport and
will not be impacted by the aircraft noise from this airport. The scope of this study includes the
noise generated by traffic on the adjacent arterials and the measures necessary to mitigate the noise
to within the exterior noise standard.
2.0 NOISE CRITERIA
The City of Carlsbad General Plan specifies outdoor and indoor noise limits for various land-uses.
The standard states that for residential land use, the exterior Community Noise Equivalent Level
(CNEL) shall not exceed 60 dB. CNEL is a 24 hour time weighted average noise level. Noise that
occurs during the evening period (7 p.m. to 10 p.m.) is weighted by 5 dB, while noise which
occurs at nighttime (10 p.m. to 7 a.m.) is weighted by 10 dB. These time periods and weights
were selected to reflect peoples sensitivity to noise during late-night and early morning hours.
3.0 METHODOLOGY
The highway noise levels projected in this report were computed using the Highway Noise Model
published by the Federal Highway Administration ("FHWA Highway Traffic Noise Prediction
Model," FHWA-RD-77-108, December 1978). The FHWA Model uses traffic volume, vehicle
mix, vehicle speed, and roadway geometry to compute the "equivalent noise level". A computer
program has been written which computes equivalent noise levels for each of the time periods used
in the calculation of CNEL. Weighting these noise levels and summing them results in the CNEL
for the traffic projections used. Noise contours are found by iterating over distance until the 60
dB, 65 dB, and 70 dB CNEL contours are found.
4.0 TRAFFIC NOISE EXPOSURE
The project will be exposed to noise from traffic on Cannon Road and El Camino Real. The future
traffic volume projections for the roadways in the project area are for the Carlsbad S ANDAG Post
2010 Land Use. These Post 2010 traffic volumes were obtained from Jim Murray, the traffic
engineer for the City of Carlsbad. The preliminary grading plans were prepared by Project Design
Consultants and dated November 1, 1996. The traffic volumes and speeds utilized are presented
in Table 1. The time and traffic distributions utilized for the analysis are from the document, "City
of Carlsbad Noise Guidelines Manual," September 1995 and are presented in Table 2. This data
was compiled by the City of Carlsbad and are based on traffic counts at 7 locations throughout the
city. The Carlsbad traffic mix is broken up into "non-truck route" traffic mix and "designated
truck route" traffic mix. The "non-truck route" traffic mix was used for both Cannon Road and H
Camino Real traffic noise models. The traffic mix for the time of day was determined from the
Orange County traffic mix which is 78% day, 12% evening, and 10% night.
MCA
TABLE 1
POST 2010 TRAFFIC VOLUMES AND SPEEDS
TRAFFIC VOLUME
ROADWAY (ADT) (MPH)
Cannon Road 31,600 SO
El Camino Real 38,300 50
TABLE 2
TRAFFIC DISTRIBUTION PER TIME OF DAY
VEHICLE TYPE DAY EVENING NIGHT
Automobile 76.35% 11.75% 9.79%
Medium Truck 1.43% 0.22% 0.18%
Heavy Truck 0.22% 0.03% 0.03%
Utilizing the traffic data presented above along with the FHWA Model, distances to the 60 dB, 65
dB and 70 dB CNEL contours were determined. The values, which are listed below in Table 3,
represent the distance from the centerline of the roadways to the contours. These projections do
not take into account any barriers, topography, or buildings that may reduce noise levels.
TABLE 3
DISTANCE TO NOISE CONTOURS FOR FUTURE CONDITIONS
ROADWAY DISTANCE TO CNEL CONTOUR (ft)
SEGMENT 70dB 65dB 60dB
Cannon Road
Soft Site Conditions 74 160 344
Ham* Site Conditions 120 379 1,197
El Camino Real
Soft Site Conditions
Hard Site Conditions
84
145
181
459
391
1,451
The units along Cannon Road will be exposed to the highest noise levels. These lots adjacent to
Cannon Road will be located between 55 to 150 feet from the centerline of Cannon Road. At these
distances, the rear yard areas will be exposed to unmitigated noise levels of 62.4 to 71.3 dBA
CNEL and the building face of the homes will be exposed to unmitigated noise levels from 64.4 to
69.4 dBA CNEL. Rear yards of Lot 121 and Lot A will experience noise from both Cannon Road
and El Camino Real for combined noise levels of 63.7 and 63.5 dBA CNEL, respectively, and the
building faces of the homes on these lots will experience combined noise levels of 66.3 and 70.0
dBA CNEL, respectively.
MGA
5.0 EXTERIOR NOISE MITIGATION
Mitigation through the design and construction of a noise barrier (wall, berm, or combination
wall/berm) is the most efficient method of reducing traffic noise levels. The effect of a noise
barrier is critically dependent on the geometry between the noise source and the receiver. A noise
barrier effect occurs when the "line of sight" between the source and receiver is broken by the
barrier. The greater the distance the sound must travel around the barrier to reach the receiver, the
greater the noise reduction of the barrier. The FHWA model was also used here in a computerized
format to determine barrier heights.
According to the site plan, the lots adjacent to Cannon Road are set back approximately 56 feet
from the roadway centerline of Cannon Road and approximately 300 feet from the roadway
centerline of El Camino Real. Some of the pad elevations at the north end of the tract are lower
than the roadway elevations. For this condition, the barriers should be placed at the edge of
roadway. In general, the barriers should be located at the top of slope whether it is at the property
line or at the top of the berm near the roadway edge.
5.1 NOISE BARRIER REQUIREMENTS TO MEET THE 60 CNEL STANDARD
A perimeter wall, 5.5 feet to 9.0 feet in height should be located along the top of slope between the
units facing Cannon Road and the roadway. Refer to Exhibit 2 for the location of the required
noise barriers. The required barriers will reduce the first floor exterior noise levels to a range of
54.6 to 59.2 dB A CNEL for the lots adjacent to Cannon Road.
The lots at the north end of the site (Lots 120, 121, and A) are also exposed to noise from traffic
along El Camino Real and will require a perimeter wall that is 6.5 to 7.0 feet high at the property
line. The pad elevation of these lots (Lots 120, 121, and A) are lower than the roadway elevation
of El Camino Real which means that a barrier located at the roadway edge would allow a lower
barrier than a barrier located at the property line. However, since only three lots along El Camino
Real need barriers, it would be more economical to place a noise barrier that is 7.0 feet tall to
surround only three lots than to have a much longer 5 foot barrier along El Camino Real. The
different barrier height locations are listed in Table 4.
TABLE 4
REQUIRED BARRIER HEIGHTS TO MEET THE 60 CNEL STANDARD
LOT NO. WALL HEIGHT (FT.)
Along El Camino Real
120
121
A
Along Cannon Road
121
A
122 to 123
124 to 127
128 to 129
131 to 134
Ito3
5 to 19
6.5
6.5
7.0
5.5
7.5
8.5
9.0
8.5
8.5
8.5
8.5
MCA
MESTRE GREVE ASSOCIATES
Exhibit!
Required Noise Barrier Location (60 CNEL)
5.2 NOISE BARRIER REQUIREMENTS TO MEET THE 65 CNEL STANDARD
A perimeter wall, 5.5 feet to 6.5 feet in height should be located along the top of slope between the
units facing Cannon Road and the roadway. Refer to Exhibit 3 for the location of the required
noise barriers. The required barriers will reduce the first floor exterior noise levels to a range of
60.1 to 64.2 dBA CNEL for the lots adjacent to Cannon Road. The different barrier height
locations are listed in Table 5.
As previously mentioned, the lots at the north end of the site (Lots 120, 121, and A) are also
exposed to noise from traffic along El Camino Real. The combined noise exposure at Lots 120,
121, and A will be 56.5, 63.7, and 63.5 dBA CNEL, respectively. Since the noise exposure at
these northern lots will be less than 65 CNEL, no barriers will be required to attenuate the traffic
noise along El Camino Real.
TABLE 5
REQUIRED BARRIER HEIGHTS TO MEET THE 65 CNEL STANDARD
LOT NO. WALL HEIGHT (FT.)
Along El Camino Real
120 No Barrier Required
121 No Barrier Required
A No Barrier Required
Along Cannon Road
121 0.0
A 5.5
122 to 123 5.5
124 to 127 6.5
128 to 129 6.0
131 to 134 6.0
1 to 3 6.0
5 to 19 6.0
5.3 NOISE BARRIER SURFACE DENSITY REQUIREMENTS
The aforementioned noise barriers are required to have a surface density of at least 3.5 pounds per
square foot, and have no openings or cracks. They may be a solid wall, an earthen berm, or a
combination of the two. They may be constructed of wood studs with stucco exterior, 3/8 inch
plate glass, 5/8 inch plexiglass, any masonry material, or a combination of these materials.
MGA
MESTRE GREVE ASSOCIATES
Exhibits
Required Noise Barrier Location (65 CNEL)
6.0 INTERIOR NOISE MITIGATION
The proposed project must comply with the City's interior noise standard of 45 dB CNEL. To
comply with the interior noise standard, the proposed buildings must provide sufficient outdoor to
indoor noise attenuation to reduce the interior noise exposure down to acceptable levels. The
projected unmitigated traffic noise exposure levels at the second floor building faces will range
from 60.1 dB CNEL to 70.0 dB CNEL. This means the structure must provide from 15.1 to 25.0
dB of exterior to interior noise reduction. When the exterior to interior noise reduction exceeds 20
dB, engineering calculations should be provided to ensure compliance with the interior noise
requirement. The calculation of the noise reduction provided by the structures can be
accomplished when the final architectural plans are completed. An additional study will be
required when architectural drawings become available identifying mitigation requirements needed
to meet the interior noise standard.
MGA
APPENDIX
CROSS SECTION DATA FOR CANNON ROAD
Lot
121
A
122
125
128
134
3
7
10
14
18
19
Road
Elevation
44.9
44.9
44.4
42
40
36.6
34.7
32.8
30.8
28.6
26.6
25.6
CL
To Wall
56
56
56
75
85
75
85
75
75
75
75
80
ED. to
Wall
50
50
50
71
81
71
81
71
71
71
71
76
Base Of
Wall
44.9
44.9
44.4
43.6
44.9
42.6
40.6
37.3
35.8
33.8
31.7
30.1
CLtO
Observer
150
61
80
80
90
80
90
80
80
80
80
85
E.D. to
Observer
144
55
74
76
86
76
86
76
76
76
76
81
Pad
Elevation
39.2
41
41.4
43.6
44.9
42.6
40.6
37.3
35.8
33.8
31.7
30.1
Observer
Height
6
6
6
6
6
6
6
6
6
6
6
6
CROSS SECTION DATA FOR EL CAMINO REAL
Lot Etamton
CL
To Wai
E.D.to Baa* Of CLto ED. to
Wai Obaarvar Obaarvar
rtn Obaarvar
•• •• « • _ • —•- JBiavawoii naiyfn
Awrfwrt Aqparfvl/n*
120 47 360
121 46.5 300
A 4S.3 345
389 39.8 365 364 39.0 6
299 39.2 305 304 393 $
344 41 350 340 41 6
MGA 8