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Home My WebLink AboutCT 95-04; Homes for Industry; Tentative Map (CT) (3)ACOUSTECH CONSULTANTS REPORT No. 1295-P33 Acoustical Analysis Report for Two Proposed Buildings on Lots 39 & 40 Airport Business Center, Carlsbad Lot 39 - MS95/05/PUD95/02/PIP95/08 Lot 40 - CT95/04/PUD95/03/PIP95/09 December 18, 1995 Prepared For: Mr. Dennis Glaser St. Georges Holdings 2223 Avenida de la Playa La Jolla, California 92037 For Submittal To: City of Carlsbad Planning Department 2075 Las Palmas Drive Carlsbad, California 92009-1576 Prepared By: Gary W. Hicks Acoustech Consultants Certified Acoustical Consultant - San Diego County Report Number 1295-P33 December 18, 1995 1 1.0 BACKGROUND 1.1 Purpose This report provides an evaluation of the interior noise levels expected for two proposed industrial buildings to be located adjacent to McClellan-Palomar Airport in the Airport Business Center 1.2 Requirements SANDAG has reviewed proposals for manufacturing buildings on lots 39 and 40 and determined that the lots are within the Carlsbad Airport Center Specific Plan. The projected 75 dBA Community Noise Equivalent Level (CNEL) noise contour for McClellan-Palomar Airport is forecasted to increase and cover portions of these lots. The buildings proposed for construction within the 75 dBA CNEL contour should be attenuated to an interior noise level of 50 dBA CNEL. 1.3 Mitigation Interior noise levels will be estimated based upon the proposed construction. If the 50 dBA CNEL limit is not achievable with standard construction, construction improvements will be recommended which will reduce interior noise levels no higher than 50 dBA CNEL. 2.0 DESCRIPTION OF SITE AND BUILDINGS 2.1 Site Location The proposed site is adjacent to the airport in the business center, north of Kellogg Avenue. Figure 2.1 illustrates the site plan and CNEL contours. 2.2 Existing Site Noise Conditions SANDAG has determined that airport traffic will result in a Community Noise Equivalent Level (CNEL) of between 70 and 75 dBA. A worst-case CNEL of 75 dBA will be assumed. 2.3 Building Characteristics The "large" building has a square footage of 10,000 square feet while the "small" building is approximately 5000 square feet. Both buildings consist of tilt-up concrete walls and an office/reception area with glass front. Key noise transmission features include the roof, a roll-up access door, and windows. Table 1 below provides the building elements and relevant areas. 10731 Old Saybrook Drive, San Diego. California 92129 Telephone & Fax (619) 672-2043 LOT 40 LOT 39 V SITE PLAN Figure 2.1 Report Number 1295-P33 December 18, 1995 3 Table 1 Areas & STC's of Building Elements (Before Upgrades) Building Element Estimated STC Areas, ft2 Bl B2 (1) Roll -up Door (standard) Access Door (standard) (2) Fixed Glass (office & walls) (3) Roof Concrete (4"-5") 15 26 27 29 46 168 21 471 5029 5180 168 21 576 9987 7501 (1) Est. 24 ga. sheet metal, minimal gasket (2) Fixed 1/4" thick single pane (3) 2"x6" joists; rooftop 5/8" plywood with paper and waterproof coating Building elements which have the greatest impact on sound transmission, in descending order are: 1. roll-up door 2. roof 3. windows The roll-up door, though small in area, generally provides poor sound insulation due to leakage at the perimeter. A higher-quality "cold weather" door may be required. The large area of the roof results in substantial noise transmission. 3.0 INTERIOR NOISE ESTIMATION METHODOLOGY 3.1 Prediction Technique To estimate the interior noise in the building, we assume that the roof and exterior walls may receive up to 75 dBA CNEL. The interior noise (Lin) can be determined by: Lin = Lout-TL+101og(S/A) w here LOU{ = the octave band exterior noise levels (total 75 dBA CNEL) TL = the octave band transmission loss of the individual building elements S = the surface area of the various building elements A = the room absorption in Sabins In practice, the composite transmission loss (TL^ for the building exterior elements is calculated based upon the individual transmission loss and areas. 10731 Old Saybrook Drive. San Diego, California 92129 Telephone & Fax (619)672-2043 Report Number 1295-P33 December 18, 1995 4 To calculate the composite transmission loss of a multi-element wall, the following equations are employed: TLC = 10 Iog10 (1AJ c = ( T^/ST) + (T^/Sp) + (T3S3/ST) - (TnSn/Sn) where TLC is the transmission loss of the multi-element wall or roof in dB. TC is the composite wall or roof transmission coefficient. Sj,S2, -ST are the areas of individual wall or roof elements. TJ, T2, ~ Tn are the sound transmission coefficients of the individual elements. ST = total wall or roof area; 2 S, +S2 — Sn The terms T,, T2, ~ xn can be calculated from the element STC values or from octave-band single element transmission loss values by solving the equation: = l/antilog10 [STC/10] OR, = t l/antilog10 [T1710] The details of the wall composite transmission loss calculations must be performed for exterior partitions which include elements other than bare stucco. 3.2 Noise Spectrum and Transmission Loss The exterior noise due to aircraft must reflect both nearby and distant aircraft. The 75 dBA CNEL is estimated to consist of the following octave band levels: Octave Band CF Est. Linear Spectrum Est. A-Wtd Spectrum 125 80 64 250 78 68 500 70 67 1000 66 66 2000 64 65 4000 62 63 10731 Old Saybrook Drive, San Diego, California 92129 Telephone & Fax (619) 672-2043 Report Number 1295-P33 December 18, 1995 5 The transmission loss of standard and upgraded building elements is as follows: Table 2 Transmission Loss of Building Elements Octave Band TL (dB) Item 125 250 500 1000 2000 4000 Est. STC (1) Roll-up door (std) 10 12 15 16.5 18 20 15 (2) Roll-up door (special) 13 17 17 20 33 36 22 Access door 19 21 24 26 26 30 26 (3) Fixed window, 3/16" 19 19 23 27 26 28 25 (4) Fixed window, 1/4" 22 25 27 31 23 31 27 (5) Tilt-up concrete wall, 4" thick 42 42 45 52 57 62 52 (6) Standard roof 15 22 27 32 35 30 29 (7) Enhanced roof 30 37 42 46 49 52 44 (1) Assumes 1" air gap on sides and bottom (2% area), 24 ga sheet metal (2) Assumes gasket material top and sides, 24 ga sheet metal; est. STC = 22 (3) (4) Aluminum frame, sealed, single pane windows (5) Solid concrete wall, Harris HB Noise Control, Fig. 31-14 (6) 5/8" plywood over 2"x6" joists, est. (7) 5/8" plywood over 2"x6" joists, R-19 insulation, 5/8" gypboard on resilient channels (Cal. HB 2.1.2.2.1.2, degraded at LF for 6" v. 8" joists) 4.0 BUILDING INTERIOR NOISE LIMITS Appendix A provides the calculation details for determining the interior noise levels in the building. The estimated values are averages; certain locations within the building may be slightly higher or lower than predicted. Table 3 below provides a summary of results. 10731 Old Saybrook Drive, San Diego, California 92129 Telephone & Fax (619) 672-2043 Report Number 1295-P33 December 18, 1995 Table 3 Predicted Interior Noise Levels Building Features Small-5000 ft2 • standard roll-up door (standu-cl) with air gaps • std roof Small (upgrade) • upgrade roll-up door with seals • upgraded roof (see below) Large-10,000 ft2 • standard roll-up door (standard) with air gaps • std roof Large • upgrade roll-up door (upgrade) with seals • upgraded roof (see below) Predicted Interior Noise (CNEL) 58.3 48.9 60.9 50.0 Required Interior Noise (CNEL) 50 50 50 50 Pass/Fail Fail Pass Fail Pass Our findings based upon the analysis are as follows: 1. The roll-up door and roof design have the greatest affect on the interior noise levels. 2. Windows and standard doors have only a small affect on the overall interior noise levels in the building. 3. Standard 1/4" or similar, single glazed, fixed windows are sufficient to meet average interior noise levels. 4. Upgraded roll-up doors and substantially upgraded roofs are required to comply with the 50 dBA CNEL limit. 5. The roll-up door should have no visible air gaps. A cold weather, high- quality door is required. Alternatively, a special custom edge seal for a standard door will be necessary. 6. The standard roof construction must be upgraded to include R-19 batt insulation between joists and 5/8" gypsum board on 1/2" resilient channels attached to the joists and spaced 24" o.c. 7. We recommend a layer of R-19 batt insulation be placed above the office/entry dropped ceiling. 10731 Old Saybrook Drive, San Diego, California 92129 Telephone & Fax (619) 672-2043 APPENDIX A Interior Noise Level Prediction Calculations Acoustech Consultants Small Building, 5000 sq. ft. Standard Door and Roof Source = 75 dBA Page! Project: Airport Business Center, Carlsbad (ROOM Lindoor 58.3 Building: 5000 ft2 I Floor Area 5029 125 Hertz Element roll-up door access door 1/4" fixed glass roof concrete 250 Hertz Element roll-up door access door 1/4" fixed glass roof concrete 500 Hertz Element roll-up door access door 1/4" fixed glass roof concrete 1000 Hertz Element roll-up door access door 1/4" fixed glass roof concrete TL 10 19 22 15 42 TL 12 21 25 22 42 TL 15 24 27 27 45 TL 16.5 26 31 32 52 Area 168.00 21.00 471.00 5029.00 5180.00 Area 168.00 21.00 471.00 5029.00 5180.00 Area 168.00 21.00 471.00 5029.00 5180.00 Area 168.00 21.00 471.00 5029.00 5180.00 TLC 10log(S/A) 17.8 23.9 28.2 10.4 72.5 A-Wt 56.5 TLC 10log(S/A) 7.4 61.5 A-Wt 52.9 TLC 10log(S/A) 5.6 44.4 A-Wt 41.2 TLC 10log(S/A) 31.7 3.4 37.7 A-Wt 37.7 12/19/95 Acoustech Consultants Small Building, 5000 sq. ft. Standard Door and Roof Source = 75 dBA PageZ 2000 Hertz Element TL Area roll-up door 18 168.00 access door 26 21.00 1/4" fixed glass 23 471.00 roof 35 5029.00 concrete 57 5180.00 TLC 10log(S/A) 32.1 3.4 36.3 A-Wt 37.5 4000 Hertz Element TL Area roll-up door 20 168.00 access door 30 21.00 1/4" fixed glass 31 471.00 roof 30 5029.00 concrete 62 5180.00 TLC 10log(S/A) 31.8 3.4 34.5 A-Wt 35.5 12/19/95 Acoustech Consultants Small Building, 5000 sq. ft. '->ecial Door and Enhanced Roof Source = 75 dBA Project: Building: Airport 5000ft- Business 1 Center,Carlsbad ROOM Lindoor | FloorArea 48.9 5029 125 Hertz Element TL roll-up door 13 access door 19 1/4" fixed glass 22 roof 30 concrete 42 Area 168.00 21.00 471.00 5029.00 5180.00 TLC 10log(S/A) 28.1 10.4 62.3 A-Wt 46.3 250 Hertz Element roll-up door access door 1/4" fixed glass roof concrete TL 17 21 25 37 42 Area 168.00 21.00 471.00 5029.00 5180.00 TLC 10log(S/A) 32.3 7.4 53.0 A-Wt 44.4 500 Hertz Element roll-up door access door 1/4" fixed glass roof concrete TL 17 24 27 42 45 Area 168.00 21.00 471.00 5029.00 5180.00 TLC 10log(S/A) 33.5 5.6 39.1 A-Wt 35.9 1000 Hertz Element TL Area roll-up door 20 168.00 access door 26 21.00 1/4" fixed glass 31 471.00 roof 46 5029.00 concrete 52 5180.00 TLC 10log(S/A) 36.8 3.4 32.6 A-Wt 32.6 12/19/95 Acoustech Consultants Small Building, 5000 sq. ft. ^ecial Door and Enhanced Roof Source = 75 dBA 2000 Hertz Element roll-up door access door 1/4" fixed glass roof concrete TL 33 26 23 49 57 Area 168.00 21.00 471.00 5029.00 5180.00 TLC 10log(S/A) 36.3 3.4 32.1 A-Wt 33.3 4000 Hertz Element TL Area roll-up door 36 168.00 access door 30 21.00 1/4" fixed glass 31 471.00 roof 52 5029.00 concrete 62 5180.00 TLC 10log(S/A) 43.6 3.4 22.8 A-Wt 23.8 12/19/95 Acoustech Consultants Large Building, 10,000 sq. ft. Standard Door and Roof Source = 75 dBA Project: Building: Airport 10,000 Business ft1 Center,Carlsbad (ROOM Lindoor Floor Area 60.9 9987 125 Hertz Element roll-up door access door 1/4" fixed glass roof concrete 250 Hertz Element roll-up door access door 1/4" fixed glass roof concrete 500 Hertz Element roll-up door access door 1/4" fixed glass roof concrete 1000 Hertz Element roll-up door access door 1/4" fixed glass roof concrete TL 10 19 22 15 42 TL 12 21 25 22 42 TL 15 24 27 27 45 TL 16.5 26 31 32 52 Area 168.00 21.00 576.00 9987.00 7501.00 Area 168.00 21.00 576.00 9987.00 7501.00 Area 168.00 21.00 576.00 9987.00 7501.00 Area 168.00 21.00 576.00 9987.00 7501.00 TLC 10log(S/A) 17.3 23.8 28.3 12.6 TLC 10log(S/A) 9.6 TLC 10log(S/A) 7.8 TLC 10log(S/A) 75.3 A-Wt 59.3 63.8 A-Wt 55.2 46.5 A-Wt 43.3 32.4 5.6 39.3 A-Wt 39.3 12/19/95 Acoustech Consultants Large Building, 10,000 sq. ft. Standard Door and Roof Source = 75 dBA 2000 Hertz Element roll-up door access door 1/4" fixed glass roof concrete TL 18 26 23 35 57 Area 168.00 21.00 576.00 9987.00 7501.00 TLC 10log(S/A) 33.2 5.6 37.4 A-Wt 38.6 4000 Hertz Element TL Area roll-up door 20 168.00 access door 30 21.00 1/4" fixed glass 31 576.00 roof 30 9987.00 concrete 62 7501.00 TLC 10log(S/A) 31.8 5.6 36.9 A-Wt 37.9 12/19/95 Acoustech Consultants Large Building, 10,000 sq. ft. "oecial Door and Enhanced Roof Source = 75 dBA Project: Building: Airpot 10,000 Business ft2 Center,Carlsbad (ROOM Lindoor Floor Area 50.0 9987 125 Hertz Element TL roll-up door 13 access door 19 1/4" fixed glass 22 roof 30 concrete 42 Area 168.00 21.00 576.00 9987.00 7501.00 TLC 10log(S/A) 29.0 12.6 63.6 A-Wt U, 47.6 250 Hertz Element roll-up door access door 1/4" fixed glass roof concrete TL 17 21 25 37 42 Area 168.00 21.00 576.00 9987.00 7501.00 TLC 10log(S/A) 33.7 9.6 53.9 A-Wt 45.3 500 Hertz Element roll-up door access door 1/4" fixed glass roof concrete TL 17 24 27 42 45 Area 168.00 21.00 576.00 9987.00 7501.00 TLC 10log(S/A) 35.2 7.8 39.6 A-Wt 36.4 1000 Hertz Element TL Area roll-up door 20 168.00 access door 26 21.00 1/4" fixed glass 31 576.00 roof 46 9987.00 concrete 52 7501.00 TLC 10log(S/A) 38.7 5.6 33.0 A-Wt L,. 33.0 12/19/95 Acoustech Consultants Large Building, 10,000 sq. ft. iccial Door and Enhanced Roof Source = 75 dBA 2000 Hertz Element TL Area roll-up door 33 168.00 access door 26 21.00 1/4" fixed glass 23 576.00 roof 49 9987.00 concrete 57 7501.00 TLC 10log(S/A) 37.6 5.6 33.0 A-Wt 34.2 4000 Hertz Element TL Area roll-up door 36 168.00 access door 30 21.00 1/4" fixed glass 31 576.00 roof 52 9987.00 concrete 62 7501.00 TLC 10log(S/A) 44.9 5.6 23.7 A-Wt 24.7 12/19/95