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HomeMy WebLinkAboutRainier Dog Resort and Spa Noise Study 7409 Greenwood Ave N, Suite A Seattle, WA 98103 P: 206.839.0819 Rainier Dog Resort and Spa Property Line Noise Report Submitted to: Sam McEntire Rainier Dog Resort and Spa Rainier Dog Resort and Spa Page 2 SSA acoustics Document Information FILE: Report – Rainier Dog Resort and Spa Noise Study PROJECT #: 24-8876 PREPARED BY: Alan Burt, P.E. Joshua Wah-Blumberg SIGNED: DATE: April 30, 2024 This report has been prepared for the titled project or named part thereof and should not be used in whole or part and relied upon for any other project without the written authorization of SSA Acoustics, LLP. SSA Acoustics, LLP accepts no responsibility or liability for the consequences of this document if it is used for a purpose other than that for which it was commissioned. Persons wishing to use or rely upon this report for other purposes must seek written authority to do s o from the owner of this report and/or SSA Acoustics, LLP and agree to indemnify SSA Acoustics, LLP for any and all resulting loss or damage. SSA Acoustics, LLP accepts no responsibility or liability for this document to any other party other than the person by whom it was commissioned. The find ings and opinions expressed are relevant to the dates of the works and should not be relied upon to represent conditions at substantially later dates. Opinions included therein are based on information gathered during the study and from our experience. If additional information becomes available which may affect our comments, conclusions or recommendations SSA Acoustics, LLP reserves the right to review the information, reassess any new potential concerns and modify our opinions accordingly. Rainier Dog Resort and Spa Page 3 SSA acoustics I. Introduction This report presents the results of a property line noise analysis conducted for the proposed Rainier Dog Resort and Spa facility at 900 S Grady Way in Renton, WA. The purpose of the analysis is to document the impact of the noise from the proposed facility to the nearest receiving properties. Noise levels from the facility were predicted to receiving properties and compared to the maximum permissible noise limits established by code. II. ZONING AND CODE REQUIREMENTS ZONING & CODE REQUIREMENTS The proposed facility will be located in the existing building on the property. According to the City of Renton, the project site and nearest adjacent properties are currently zoned as follows: Table 1 – Zoning and EDNA Classification of Project Site and Surrounding Properties Property Parcel # Zoning Use EDNA Classification Project Site 1723059021 CD Commercial Class B North 2570290000 R-14 Residential Class A Northeast 1723059054 CD Residential Class A Southeast (Across S Grady Way) 1723059072 CA Commercial Class B West (Across Williams Ave S) 1723059137, 1723059078 R-14 Residential Class A Southwest (Across Williams Ave S) 1723059136, 9423500000 R-14 Residential Class A Renton Municipal Code Chapter 8-7-2 adopts WAC Section 173-60 by reference. Washington Administrative Code (WAC) Section 173-60 identifies residential properties as Class A EDNA and commercial properties as Class B EDNA. Under WAC 173-60, Maximum Permissible Environmental Noise Levels, noise from a Class B EDNA property is limited as follows: Class A EDNA Receiver: Noise is limited to 57 dBA during daytime hours. During nighttime hours, between the hours of 10 p.m. and 7 a.m., the maximum permissible sound level is decreased by 10 decibels. Class B EDNA Receiver: Noise is limited to 60 dBA 24 hours a day. In addition, during any hour of the day or night the applicable noise limitations may be exceeded for any receiving property by no more than: (a) 5 dBA for a total of 15 minutes in any one-hour period; or (b) 10 dBA for a total of 5 minutes in any one-hour period; or (c) 15 dBA for a total of 1.5 minutes in any one-hour period. The facility will board dogs during daytime and nighttime hours. Therefore, noise from the facility must not exceed the daytime and nighttime noise limits at the surrounding receiving properties. Rainier Dog Resort and Spa Page 4 SSA acoustics Figure 1 – Project Site and Surrounding Properties (City of Renton GIS) Rainier Dog Resort and Spa Page 5 SSA acoustics AMBIENT NOISE LEVELS Existing ambient noise levels were measured on site with (1) Svantek 971 noise monitor and (1) Svantek 979 sound level meter. Figure 2 below shows the measurement locations. Noise monitoring was conducted over a 24-hour period from 12:00 AM to 12:00 AM on 4/9/2024 at location M1 to capture hourly noise levels, and short-term measurements were conducted on 4/11/2024 at the monitoring location, and locations S2, S3, and S4. The weather during the measurements was primarily overcast. Additional information is provided in the appendix. Figure 2 – Measurement Locations Table 2 – Summary of Noise Monitoring Time of Day M1 Hourly Leq Range (dBA) Daytime 58 – 65 Nighttime 55 – 63 Table 3 – Summary of Short-Term Measurements Location Ambient Noise Level (dBA) M1 59 S2 57 S3 67 S4 60 Rainier Dog Resort and Spa Page 6 SSA acoustics III. Predicted Noise Levels FACILITY DESCRIPTION The kennels will be located within the existing building at the site. The building construction is metal frame, with insulation, structural sheathing, and metal siding, with GWB on the interior of the walls. The GWB in the kennel room, holding area, reception, and luxury suites extends all the way to the ceiling. The GWB on the inside of the walls of play rooms 1 and 2 stop at approximately 12’ A.F.F. There is a glass, exterior, double door to the reception room on the southeast side of the building, a metal exterior door to the kennel room on the northeast side of the building, and a metal, exterior, double door and metal roll-up door to play room 2 on the northwest side of the building. The exterior door to the kennel room has a full set of acoustical seals that prevent noise from passing through gaps at the perimeter of the door. The following figure presents a diagram of the building that shows the approximate locations of the dog kennel room, play room 1, play room 2, reception, and holding area. The luxury suites will be located on the second floor on the south side of the building, directly above the holding area and reception room. Figure 3 – Building Layout Rainier Dog Resort and Spa Page 7 SSA acoustics The interior to exterior noise reduction of the building was measured for use in predicting the noise levels. The following table provides a summary of the noise reduction from various parts of the building: Table 4 - Noise Reduction of Building Elements Wall / Condition Noise Reduction (dBA) NE and SE Façades of Kennel Room 34 SE Façade of Play Room 1 29 NW Façade of Play Room 2 25 SW Façade of Holding Area 42 Barking dogs are the loudest primary noise sources associated with the facility. Noise levels from the barking dogs were predicted using reference sound levels measured in a similar facility. Based on this data, the noise level of 1 dog barking is 89 dBA Leq and 104 dBA Lmax. The Leq level represents the noise level from a source averaged over the duration of the event. The Lmax level represents the maximum instantaneous level of the event. During daytime hours, the dogs will be kept in the kennels or luxury suites, unless they are in the indoor play rooms, or in one of the outdoor yards or outdoor potty areas. Up to 20 dogs will be allowed into play room 1, and up to 5 dogs will be allowed into play room 2. Additionally, up to 18 dogs can be kept in the holding area during daytime hours. Dogs must pass a temperament evaluation to be allowed into the outdoor yards, so play is typically quiet, and if a dog starts barking, it will be returned to its kennel immediately. During nighttime hours, up to 28 dogs will be kept inside of the kennel room, and up to 6 dogs will be kept in the luxury suites. The following table presents a summary of the cumulative average and maximum noise levels from the maximum number of dogs barking in each room. This represents the worst-case scenario of all of the dogs barking in each type of room. Table 5 – Cumulative Noise Levels – Multiple Dogs Barking Number of Dogs Barking Room Cumulative Noise Level, Leq (dBA) Cumulative Noise Level, Lmax (dBA) 5 Play Room 2 96 111 6 Luxury Suites 97 112 18 Holding Area 102 117 20 Play Room 1 102 117 28 Kennel Room 104 119 Rainier Dog Resort and Spa Page 8 SSA acoustics Predicted Noise Levels: Kennel Room (Daytime and Nighttime) The following tables present the predicted noise levels from dogs barking in the kennel room to the nearest receiving properties: Table 6 – Predicted Average Noise Levels (Leq) of (28) Dogs Barking in Kennel Room Source Receiving Property Sound Level Leq, dBA1 Ref Dist. (ft) Receiver Dist. (ft) Building Reduction2 Distance Reduction3 Lp,r dBA (28) Dogs Barking North 104 3 113 -34 -32 38 (28) Dogs Barking Northeast 104 3 65 -34 -27 43 (28) Dogs Barking Southeast 104 3 125 -34 -32 38 Table Notes: 1. Cumulative noise level of 28 dogs barking in the kennel room. 2. Noise reduction through facility walls and barrier reduction from intervening building elements. 3. Distance Factor = -10*LOG(Q)+20*LOG(R2/R1). As shown in the table above, the average noise levels from the worst-case scenario of 28 dogs barking in the kennel room will meet the 47 dBA hourly nighttime code limit and the 57 dBA hourly daytime code limit at the north and northeast receiving properties, and the 60 dBA hourly code limit at the southeast receiving property. Noise levels at other receiving properties, which are further away, will be lower and within code limits. Additionally, the predicted noise levels are significantly below the current ambient noise levels and will be barely perceptible. Table 7 – Predicted Max Noise Levels (Lmax) – (28) Dogs Barking in Kennel Room Source Receiving Property Sound Level Lmax, dBA1 Ref Dist. (ft) Receiver Dist. (ft) Building Reduction2 Distance Reduction3 Lp,r dBA (28) Dogs Barking North 119 3 113 -34 -32 53 (28) Dogs Barking Northeast 119 3 65 -34 -27 58 (28) Dogs Barking Southeast 119 3 125 -34 -32 53 Table Notes: 1. Cumulative noise level of 28 dogs barking in the kennel room. 2. Noise reduction through facility walls and barrier reduction from intervening building elements. 3. Distance Factor = -10*LOG(Q)+20*LOG(R2/R1). As shown in the table above, the maximum noise levels from 28 dogs barking in the kennel room will meet the 72 dBA 1.5-minute daytime code limit and the 62 dBA nighttime code limit at the north and northeast receiving properties, and the 75 dBA 1.5-minute code limit at the southeast receiving property. Rainier Dog Resort and Spa Page 9 SSA acoustics Predicted Noise Levels: Luxury Suites (Daytime and Nighttime) The following tables present the predicted average and maximum noise levels from 6 dogs barking in the luxury suites to the nearest receiving properties: Table 8 – Predicted Average Noise Levels (Leq) of (6) Dogs Barking in Luxury Suites Source Receiving Property Sound Level Leq, dBA1 Ref Dist. (ft) Receiver Dist. (ft) Building Reduction2 Distance Reduction3 Lp,r dBA (6) Dogs Barking West 97 3 118 -42 -32 23 (6) Dogs Barking Southwest 97 3 87 -42 -29 26 (6) Dogs Barking Southeast 97 3 125 -42 -32 23 Table Notes: 1. Cumulative noise level of 6 dogs barking in the luxury suites. 2. Noise reduction through facility walls and barrier reduction from intervening building elements. 3. Distance Factor = -10*LOG(Q)+20*LOG(R2/R1). As shown in the table above, the average noise levels from 6 dogs barking in the luxury suites will meet the 57 dBA hourly daytime code limit and the 47 dBA hourly nighttime code limit at the west and southwest receiving properties and the 60 dBA hourly code limit at the southeast receiving property. Noise levels at other receiving properties, which are further away, will be lower and within code limits. Additionally, the predicted noise levels are significantly below the current ambient noise levels and will be barely perceptible. Table 9 – Predicted Max Noise Levels (Lmax) of (6) Dogs Barking in Luxury Suites Source Receiving Property Sound Level Lmax, dBA1 Ref Dist. (ft) Receiver Dist. (ft) Building Reduction2 Distance Reduction3 Lp,r dBA (6) Dogs Barking West 112 3 118 -42 -32 38 (6) Dogs Barking Southwest 112 3 87 -42 -29 41 (6) Dogs Barking Southeast 112 3 125 -42 -32 38 Table Notes: 1. Cumulative noise level of 6 dogs barking in the luxury suites. 2. Noise reduction through facility walls and barrier reduction from intervening building elements. 3. Distance Factor = -10*LOG(Q)+20*LOG(R2/R1). As shown in the table above, the maximum noise levels from 6 dogs barking in the luxury suites will meet the 72 dBA 1.5-minute daytime code limit and the 62 dBA 1.5-minute nighttime code limit at the west and southwest receiving properties and the 75 dBA 1.5-minute code limit at the southeast receiving property. Additionally, the predicted noise levels are significantly below the current ambient noise levels and will be barely perceptible. Rainier Dog Resort and Spa Page 10 SSA acoustics Predicted Noise Levels: Holding Area (Daytime Only) The following tables present the predicted average and maximum noise levels from 18 dogs barking in the holding area to the nearest receiving properties: Table 10 – Predicted Average Noise Levels (Leq) of (18) Dogs Barking in Holding Area Source Receiving Property Sound Level Leq, dBA1 Ref Dist. (ft) Receiver Dist. (ft) Building Reduction2 Distance Reduction3 Lp,r dBA (18) Dogs Barking West 102 3 118 -42 -32 28 (18) Dogs Barking Southwest 102 3 87 -42 -29 31 (18) Dogs Barking Southeast 102 3 141 -42 -33 27 Table Notes: 1. Cumulative noise level of 18 dogs barking in the holding area. 2. Noise reduction through facility walls and barrier reduction from intervening building elements. 3. Distance Factor = -10*LOG(Q)+20*LOG(R2/R1). As shown in the table above, the average noise levels from 18 dogs barking in the holding area will meet the 57 dBA hourly daytime code limit at the west and southwest receiving properties, and the 60 dBA hourly code limit at the southeast receiving property. Noise levels at other receiving properties, which are further away, will be lower and within code limits. Additionally, the predicted noise levels are significantly below the current ambient noise levels and will be barely perceptible. Table 11 – Predicted Max Noise Levels (Lmax) of (18) Dogs Barking in Holding Area Source Receiving Property Sound Level Lmax, dBA1 Ref Dist. (ft) Receiver Dist. (ft) Building Reduction2 Distance Reduction3 Lp,r dBA (18) Dogs Barking West 117 3 118 -42 -32 43 (18) Dogs Barking Southwest 117 3 87 -42 -29 46 (18) Dogs Barking Southeast 117 3 141 -42 -33 42 Table Notes: 1. Cumulative noise level of 18 dogs barking in the holding area. 2. Noise reduction through facility walls and barrier reduction from intervening building elements. 3. Distance Factor = -10*LOG(Q)+20*LOG(R2/R1). As shown in the table above, maximum noise levels from 18 dogs barking in the holding area will meet the 72 dBA 1.5-minute daytime code limit at the west and southwest receiving properties and the 75 dBA 1.5-minute code limit at the southeast receiving property. Noise levels at other receiving properties, which are further away, will be lower and within code limits. Additionally, the predicted noise levels are significantly below the current ambient noise levels and will be barely perceptible. Rainier Dog Resort and Spa Page 11 SSA acoustics Predicted Noise Levels: (20) Barking Dogs in Play Room 1 (Daytime Only) The following tables present the predicted average and maximum noise levels from (20) dogs barking in Play Room 1 to the nearest receiving properties: Table 12 – Predicted Average Noise Levels (Leq) of (20) Dogs Barking in Play Room 1 Source Receiving Property Sound Level Leq, dBA1 Ref Dist. (ft) Receiver Dist. (ft) Building Reduction2 Distance Reduction3 Lp,r dBA (20) Dogs Barking Northeast 102 3 147 -29 -34 39 (20) Dogs Barking Southeast 102 3 120 -29 -32 41 Table Notes: 1. Cumulative noise level of 20 dogs barking in play room 1. 2. Noise reduction through facility walls and barrier reduction from intervening building elements. 3. Distance Factor = -10*LOG(Q)+20*LOG(R2/R1). As shown in the table above, the average noise levels from (20) dogs barking in Play Room 1 will meet the 57 dBA hourly daytime code limit at the northeast receiving property and the 60 dBA hourly code limit at the southeast receiving property. Noise levels at other receiving properties, which are further away, will be lower and within code limits. Additionally, the predicted noise levels are significantly below the current ambient noise levels and will be barely perceptible. Table 13 – Predicted Max Noise Levels (Lmax) of (20) Dog Barking in Play Room 1 Source Receiving Property Sound Level Lmax, dBA1 Ref Dist. (ft) Receiver Dist. (ft) Building Reduction2 Distance Reduction3 Lp,r dBA (20) Dogs Barking Northeast 117 3 97 -29 -34 54 (20) Dogs Barking Southeast 117 3 120 -29 -32 56 Table Notes: 1. Cumulative noise level of 20 dogs barking in play room 1. 2. Noise reduction through facility walls and barrier reduction from intervening building elements. 3. Distance Factor = -10*LOG(Q)+20*LOG(R2/R1). As shown in the table above, the maximum noise levels from 20 dogs barking in Play Room 1 will meet the 72 dBA 1.5-minute daytime code limit at the northeast receiving property and the 75 dBA 1.5-minute code limit at the southeast receiving property. Noise levels at other receiving properties, which are further away, will be lower and within code limits. Rainier Dog Resort and Spa Page 12 SSA acoustics Predicted Noise Levels: (5) Barking Dogs in Play Room 2 (Daytime Only) The following tables present the predicted average and maximum noise levels from 5 dogs barking in Play Room 2 to the surrounding receiving properties: Table 14 – Predicted Average Noise Levels (Leq) of (5) Dogs Barking in Play Room 2 Source Receiving Property Sound Level Leq, dBA1 Ref Dist. (ft) Receiver Dist. (ft) Building Reduction2 Distance Reduction3 Lp,r dBA (5) Dogs Barking North 96 3 80 -25 -29 42 (5) Dogs Barking Northeast 96 3 55 -25 -25 46 (5) Dogs Barking West 96 3 96 -25 -30 41 (5) Dogs Barking Southwest 96 3 90 -25 -30 41 (5) Dogs Barking Southeast 96 3 163 -25 -35 36 Table Notes: 1. Cumulative noise level of 5 dogs barking in play room 2. 2. Noise reduction through facility walls and barrier reduction from intervening building elements. 3. Distance Factor = -10*LOG(Q)+20*LOG(R2/R1). As shown in the table above, the average noise levels from 5 dogs barking in Play Room 2 will meet the 57 dBA hourly daytime code limit at the north, northeast, west, and southwest receiving properties and the 60 dBA hourly code limit at the southeast receiving property. Additionally, the predicted noise levels are significantly below the current ambient noise levels and will be barely perceptible. Table 15 – Predicted Max Noise Levels (Lmax) of (5) Dogs Barking in Play Room 2 Source Receiving Property Sound Level Lmax, dBA1 Ref Dist. (ft) Receiver Dist. (ft) Building Reduction2 Distance Reduction3 Lp,r dBA (5) Dogs Barking North 111 3 80 -25 -29 57 (5) Dogs Barking Northeast 111 3 55 -25 -25 61 (5) Dogs Barking West 111 3 96 -25 -30 56 (5) Dogs Barking Southwest 111 3 90 -25 -30 56 (5) Dogs Barking Southeast 111 3 163 -25 -35 51 Table Notes: 1. Cumulative noise level of 5 dogs barking in play room 2. 2. Noise reduction through facility walls and barrier reduction from intervening building elements. 3. Distance Factor = -10*LOG(Q)+20*LOG(R2/R1). As shown in the table above, the maximum noise levels from 5 dogs barking in Play Room 2 will meet the 72 dBA 1.5-minute daytime code limit at the north, northeast, west, and southwest receiving properties and the 75 dBA 1.5-minute code limit at the southeast receiving property. Rainier Dog Resort and Spa Page 13 SSA acoustics Predicted Noise Levels: Outdoor Yards (Daytime Only) If a dog passes a temperament examination, it will be allowed to play outside in the yards during daytime hours. Up to 5 dogs will be allowed in either of the two yards at a time, so up to a total of 10 dogs will be allowed in the yards. Outdoor play will generally be quiet, and if a dog barks, it will immediately be returned to its kennel inside of the building. Therefore, for the purposes of this study, it is assumed that noise from a dog barking in the yard will be instantaneous and only last a short duration, so the Lmax noise levels are compared to the 1.5-minute daytime code limits at the receiving properties. The following figure shows the proposed yard area: Figure 4 – Proposed Yard Area The following table presents the predicted maximum noise levels from (1) dog barking in the closest area of the yards to each receiving property: Table 16 – Predicted Max Noise Levels (Lmax) of (1) Dog Barking in the Outdoor Yards Source Receiving Property Sound Level Lmax, dBA Ref Dist. (ft) Receiver Dist. (ft) Distance Reduction1 Lp,r dBA (1) Dog Barking North 104 3 3 0 104 (1) Dog Barking Northeast 104 3 3 0 104 (1) Dog Barking West 104 3 75 -28 76 (1) Dog Barking Southwest 104 3 82 -29 75 (1) Dog Barking Southeast 104 3 90 -30 74 Table Notes: 1. Distance Factor = -10*LOG(Q)+20*LOG(R2/R1). As shown in the table above, the maximum noise levels from (1) dog barking in the outdoor yards do not meet the 72 dBA 1.5-minute daytime code limit at the north, northeast, west and southwest receiving properties. The maximum noise level from (1) dog barking in the outdoor yards meets the 75 dBA 1.5-minute code limit at the southeast receiving property. In order to meet code, the noise mitigation measures described in the following section must be implemented. Rainier Dog Resort and Spa Page 14 SSA acoustics Noise Mitigation The following noise control measures must be implemented to ensure the noise from a dog barking in the yard areas will meet the code limits: • Limit the yard area available to the dogs, as shown by the green area in Figure 6, and ensure that dogs are not able to be within 15 feet of the north and northeast receiving properties. • Construct noise barriers on the north, west, east, and south sides of the yards, as shown by the bold red and blue lines in Figure 5. • The top of the noise barriers shown in red that run along the north side of the yards shall be at least 8’-0” above grade. The top of the noise barriers shown in blue shall be at least 6’-0” above grade. • Construct the noise barriers with a solid material that has a surface mass of at least 4.0 lbs/sq ft. The following are common barrier materials that meet this requirement: o (2) layers of 3/4" exterior grade plywood o (2) layers of 16-gauge sheet metal o (2) layers of HardiePanel • Install acoustical panels on all available surfaces along the dog-facing side of the barriers. Panels to have a minimum NRC of 0.80. Open metal grid materials, like chicken wire, may be added to the face of the sound absorbing material to prevent dogs from chewing on it. The following are recommended products for this application: o 2” thick Polysorb: Contact Ken Huber at Snap-Tex for Polysorb pricing etc: 206-789-2413, ken@snaptex.com o 2” thick FSorb • A detail of the barrier construction is presented in figure 6. Rainier Dog Resort and Spa Page 15 SSA acoustics Figure 5 – Outdoor Yard Noise Mitigation - Plan Figure 6 – Noise Barrier Detail Rainier Dog Resort and Spa Page 16 SSA acoustics Predicted Noise Levels – With Mitigation The following table presents the predicted noise levels from (1) dog barking in the outdoor yards to the nearest receiving properties with noise mitigation implemented: Table 17 – Predicted Noise Levels (Lmax) of (1) Dog Barking in the Outdoor Yards w/ Mitigation Source Receiving Property Sound Level Lmax, dBA Ref Dist. (ft) Receiver Dist. (ft) Barrier Reduction1 Distance Reduction2 Lp,r dBA (1) Dog Barking North 104 3 15 -18 -14 72 (1) Dog Barking Northeast 104 3 15 -18 -14 72 (1) Dog Barking West 104 3 75 -16 -28 60 (1) Dog Barking Southwest 104 3 82 -16 -29 59 Table Notes: 1. Noise barrier reduction. 2. Distance Factor = -10*LOG(Q)+20*LOG(R2/R1). As shown in the table above, maximum noise levels from (1) dog barking in the outdoor yards with noise mitigation implemented will meet the 72 dBA 1.5-minute daytime code limit at all of the receiving properties. Noise levels at other receiving properties, which are further away, will be lower and within code limits. SUMMARY This concludes the noise study for the Rainier Dog Resort and Spa. The study shows that noise levels from dogs barking within the facility will meet the code limits at the surrounding receiving properties. Noise mitigation measures will be necessary to ensure dogs barking in the outdoor yards will meet code limits at the receiving properties. Please contact us if you have questions or need additional information. Rainier Dog Resort and Spa Page 17 SSA acoustics APPENDIX I: ACOUSTICAL DESCRIPTORS Sound is measured as sound level in units of decibels, dB. The human ear responds differently to sounds at different frequencies. This is demonstrated by the fact that we hear higher pitched sounds more easily than lower ones of the same magnitude. To compensate for the different “loudness” as perceived by humans, a standard weighting curve is applied to measured sound levels. The weighting curve represents the frequency response of the human ear and is labeled as dBA (“A” weighted decibels). People normally experience sound levels between 30 and 90 dBA, depending on their activities. Locations near highways or urban arterials may be 70 dBA, whereas quiet rural areas may be 40 dBA. Each 10 dB increase in sound level corresponds to a tenfold increase of sound energy but is judged by a listener as only a doubling of loudness. The smallest changes in sound level considered just noticeable are about 2 to 3 dBA. Sound levels from two or more sources are combined logarithmically, not by adding the levels arithmetically. When two levels are combined, the louder level predominates, and the combined level is the louder level plus 0 to 3 dBA. Some examples: 50 dBA combined with 50 dBA is 5 3 dBA; 50 dBA combined with 40 dBA results in 50.4 dBA, which is rounded off to 50 dBA since fractions of a dB are negligible from the point of view of perception of environmental noise. When measuring noise that is fluctuating over time, it is common practice to use a descriptor called equivalent A-weighted sound level, Leq. The Leq is that constant sound level in dBA which contains the same amount of sound energy over a given time period as the measured fluctuating noise. The Leq is often determined for one-hour time periods. Another descriptor is the Lmax. The Lmax is the highest instantaneous sound level for a given sound event or time period. Similarly, Lmin is the lowest instantaneous sound level for a given sound event or time period. Rainier Dog Resort and Spa Page 18 SSA acoustics APPENDIX II: Noise Monitor Results