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HomeMy WebLinkAboutRS_KCESI2_Noise_Criteria_TM_181207_v2.pdf p) 206.378.0569 f) 206.378-0641 www.greenbusch.com 1900 West Nickerson Street, Suite 201 Seattle, WA 98119 DATE: December 6, 2018 TO: Erik Waligorski, PE – Carollo Engineers, Inc. FROM: Adam C. Jenkins, PE(OR), INCE Bd. Cert. Drew Savas RE: Eastside Interceptor Section 2 Rehabilitation Phase II – Noise Criteria Transmitted by: Mail Delivery Fax E-mail INTRODUCTION The intent of this memorandum is to present proposed noise design criteria and a summary of ambient sound level measurements conducted in the area of the Eastside Interceptor Section 2 Rehabilitation Phase II Project (“Project”) in Renton, Washington. SUMMARY Sounds originating from temporary construction sites are exempt from the City of Renton noise code, except when sounds are received at Class A EDNAs during nighttime hours. The City of Renton groups properties into three noise districts called Environmental Designations for Noise Abatement (“EDNA”). Properties are placed in one of the three groups based on their use, as defined by Section 8-7-4 of the City of Renton Municipal Code (“RMC”). If construction activities will be conducted during nighttime hours near Class A EDNA properties, a noise variance from the City of Renton would be needed. Additionally, King County’s Guide Specification limits sounds originating from construction equipment to 90 dBA for scrapers, pavers, graders, and trucks, 95 dBA for pile drivers, and 85 dBA for all other equipment when measured at 50 feet, at all times. NOMENCLATURE Decibel The auditory response to sound is a complex process that occurs over a wide range of frequencies and intensities. Decibel levels, or “dB,” are a form of shorthand that compresses this broad range of intensities with a convenient numerical scale. The decibel scale is logarithmic. For example, using the decibel scale, a doubling or halving of energy causes the sound level to change by 3 dB; it does not double or halve the sound loudness as might be expected. The minimum sound level variation perceptible to a human observer is generally around 3 dB. A 5-dB change is clearly perceptible, and an 8 to 10 dB change is associated with a perceived doubling or halving of loudness. The human ear has a unique response to sound pressure. It is less sensitive to those sounds falling outside the speech frequency range. Sound level meters and monitors utilize a filtering system to approximate human perception of sound. Measurements made utilizing this filtering system are referred to as “A weighted” and are called “dBA”. December 6, 2018 Page 2 Eastside Interceptor Section 2 Rehabilitation Phase II - Noise Criteria The Greenbusch Group, Inc. p) 206.378.0569 f) 206.378-0641 www.greenbusch.com 1900 West Nickerson Street, Suite 201 Seattle, WA 98119 Common sound pressure levels are presented in Table 1. Table 1. A-weighted Levels of Common Sounds Sound Sound Level (dBA) Approximate Relative Loudness1 Jet Plane @ 100 feet 130 128 Rock Music with Amplifier 120 64 Thunder, Danger of Permanent Hearing Loss 110 32 Boiler Shop, Power Mower 100 16 Orchestral Crescendo at 25 feet 90 8 Busy Street 80 4 Interior of Department Store 70 2 Ordinary Conversation at 3 feet 60 1 Quiet Car at Low Speed 50 1/2 Average Office 40 1/4 City Residence, Interior 30 1/8 Quiet Country Residence, Interior 20 1/16 Rustle of Leaves 10 1/32 Threshold of Hearing 0 1/64 1. As compared to ordinary conversation at 3 feet. Source: US Department of Housing and Urban Development, Aircraft Noise Impact Planning Guidelines for Local Agencies, November 1972. Metrics • Ambient Sound Level A sound pressure level that describes the average sound environment at a specified location during a specified time period including contributions from all sound sources, both local and distant, excluding specific sources of interest or under investigation. • Equivalent Sound Level, Leq Leq is the A-weighted level of a constant sound having the same energy content as the actual time-varying level during a specified interval. The Leq is used to characterize complex, fluctuating sound levels with a single number. Typical intervals for Leq are hourly, daily and annually. • Sound Pressure Level, SPL Sound pressure level correlates with what is heard by the human ear. SPL is defined as the squared ratio of the sound pressure with reference to 20 μPa. Sound pressure is affected by distance, path, barriers, directivity, etc. December 6, 2018 Page 3 Eastside Interceptor Section 2 Rehabilitation Phase II - Noise Criteria The Greenbusch Group, Inc. p) 206.378.0569 f) 206.378-0641 www.greenbusch.com 1900 West Nickerson Street, Suite 201 Seattle, WA 98119 ZONING AND REGULATORY CRITERIA Properties surrounding the Project area consist of residential, commercial and industrial use. As of September 19th, 2018, the City of Renton no longer groups multiple zoning designations into noise districts called Environmental Designations for Noise Abatement (“EDNA”). Instead, the City has amended Section 8-7-4 of the RMC to adopt Section 173-60-30 of the Washington Administrative Code (“WAC”). Section 173-60-030 defines EDNA classifications by land use, not zoning. Generally, Class A EDNA includes residential use properties, Class B EDNA includes commercial use properties and Class C EDNA includes industrial use properties. Figure 1 provides a graphical representation of EDNAs in the Project area, along with the Project alignment. Figure 1. Project Location and Nearby EDNAs Source: King County iMap, The Greenbusch Group, Inc., Bing Maps, City of Renton December 6, 2018 Page 4 Eastside Interceptor Section 2 Rehabilitation Phase II - Noise Criteria The Greenbusch Group, Inc. p) 206.378.0569 f) 206.378-0641 www.greenbusch.com 1900 West Nickerson Street, Suite 201 Seattle, WA 98119 Environmental Sound Level Limits City of Renton Maximum permissible environmental sound levels are defined by Section 8-7-2 of the RMC which adopts Section 173-60-040 of the W AC. These sound level limits are based on the EDNA the sound source originates within (EDNA of Sound Source) and in which EDNA the sound is received (EDNA of Receiving Property). A summary of the applicable sound level limits can be found in Table 2. Table 2. Environmental Sound Level Limits, Leq EDNA of Sound Source EDNA of Receiving Property Class A Class B Class C Class A 55 dBA 57 dBA 60 dBA Class B 57 dBA 60 dBA 65 dBA Class C 60 dBA 65 dBA 70 dBA Source: Section 8-7-2 City of Renton Municipal Code, Section 173-60-040 Washington Administrative Code Modifications Modifications to the environmental sound level limits set forth in Table 2 are also outlined in Section 173-60-040 of the WAC. These modifications are for certain times of day and classification of receiving properties. These modifications to the environmental sound level limits include the following: • 10 dBA reduction during the nighttime hours between the hours of 10 p.m. and 7 a.m. when the receiving property is within Class A EDNAs. Exemptions Section 173-60-050 of the WAC referenced by Section 8-7-2 of the RMC allows exemptions from environmental sound level limits set forth in Table 2. Applicable exemptions include all sounds originating from temporary construction sites as a result of construction activity that are received in Class B and Class C EDNAs, and in Class A EDNA between the hours of 7 a.m. and 10 p.m.. Construction activities which generate sounds received in Class A EDNAs between 10 p.m. and 7 a.m. would need to comply with sound level limits in Table 2. It is our interpretation of the RMC that all construction equipment, including bypass pumps and blowers, would be exempt. December 6, 2018 Page 5 Eastside Interceptor Section 2 Rehabilitation Phase II - Noise Criteria The Greenbusch Group, Inc. p) 206.378.0569 f) 206.378-0641 www.greenbusch.com 1900 West Nickerson Street, Suite 201 Seattle, WA 98119 PROJECT-SPECIFIC CRITERIA King County Guide Specification Section 01 35 43 defines sound level limits and general noise control requirements for the Project, as summarized below. • Sound Level Limits o Noise levels for scrapers, pavers, graders, and trucks shall not exceed 90 dBA and pile drivers shall not exceed 95 dBA at 50 feet as measured under the noisiest operating conditions. o For other equipment, noise levels shall not exceed 85 dBA. Equipment that cannot meet these levels shall be quieted by use of improved exhaust mufflers, noise attenuation barriers or other means. • General Noise Control Requirements o Noise complaints received by the Project Representative during the Work will be shared with the contractor. Work with the Project Representative, as required, to resolve noise related complaints. o Noisy operations shall be scheduled to minimize their impact. o Unless otherwise indicated through a noise variance, comply with local controls and noise level rules, regulations, and ordinances which apply to work performed. o Each internal combustion engine, used on the job or related to the job, shall be equipped with a muffler of a type recommended by the manufacturer. No internal combustion engine shall be operated without said muffler. o Use electric or hydraulic tools whenever practical to reduce noise. o Provide notification of special circumstances or emergency conditions that require work beyond the hours specified as follows: ▪ Notify the Project Representative and local authority in advance of any proposed extended work hours for preauthorization. Include a written request for authorization per Section01 14 00 to perform work specified and the circumstances that warrant this request. Include any additional measures to mitigate noise generated by this construction activity if deemed necessary by the Project Representative. ▪ If an emergency situation occurs that warrants extended hours, notify the Project Representative immediately upon determining the need for this work. December 6, 2018 Page 6 Eastside Interceptor Section 2 Rehabilitation Phase II - Noise Criteria The Greenbusch Group, Inc. p) 206.378.0569 f) 206.378-0641 www.greenbusch.com 1900 West Nickerson Street, Suite 201 Seattle, WA 98119 AFFECTED ENVIRONMENT Existing Sound Levels Continuous sound level monitoring was performed at two locations in the Project area. One monitoring location (Location 1) was a small wooded area between Lake Washington Boulevard North and Northeast Park Drive. This location was chosen to capture representative ambient sound levels of the northern extent of the Project. The second monitoring location (Location 2) was the southwest corner of the North 6th Street and Burnett Avenue North intersection. This location was chosen to measure representative ambient sound levels of the southern extent of the construction alignment. Measurements were conducted between Monday December 11th, 2017 at 12 p.m. and Thursday December 14th, 2017 at 12 p.m. Local noise sources, at both locations, included local traffic, rail traffic, commercial activities, and nature sounds. Equipment used during the measurements is identified in Table 3. Table 3. Measurement Equipment Make and Model Description Serial Classification Svantek 971 Sound Level Meter 51818 ANSI Type 1 (S1.4 and S1.43) Svantek SV18 Preamplifier 49561 Aco Pacific 7052E Microphone 62522 B&K 2250 Sound Level Meter 3006756 B&K ZC-0032 Preamplifier 24600 B&K 4189 Microphone 2550228 Source: The Greenbusch Group, Inc. All equipment was factory calibrated within 1 year of the measurement date. Field calibrations were performed before the measurements and verified immediately after the measurements were completed. Measurement results are summarized in Table 4. Measurement locations and equipment are shown in Figures 2 through 4 Table 4. Measured Hourly Leq Sound Levels, Low-High (Average), dBA Monitoring Location Weekday Daytime (7 AM – 10 PM) Nighttime (10 PM – 7 AM) Location 1 (North) 60 – 68 (65) 53 – 65 (60) Location 2 (South) 59 – 71 (61) 53 – 61 (59) Source: The Greenbusch Group, Inc. December 6, 2018 Page 7 Eastside Interceptor Section 2 Rehabilitation Phase II - Noise Criteria The Greenbusch Group, Inc. p) 206.378.0569 f) 206.378-0641 www.greenbusch.com 1900 West Nickerson Street, Suite 201 Seattle, WA 98119 Figure 2. Ambient Monitoring Locations Source: The Greenbusch Group, Inc., Bing Maps December 6, 2018 Page 8 Eastside Interceptor Section 2 Rehabilitation Phase II - Noise Criteria The Greenbusch Group, Inc. p) 206.378.0569 f) 206.378-0641 www.greenbusch.com 1900 West Nickerson Street, Suite 201 Seattle, WA 98119 Figure 3. Location 1 (North) Figure 4. Location 2 (South) PROPOSED DESIGN CRITERIA Sounds originating from temporary construction sites as a result of construction activity that are received in Class B and Class C EDNAs, and in Class A EDNA between the hours of 7 a.m. and 10 p.m. do not need to comply with the maximum environmental sound level limits. However, King County’s Guide Specification requires that sound levels from scrapers, pavers, graders, and trucks to not exceed 90 dBA, pile drivers to not exceed 95 dBA and other equipment to not exceed 85 dBA when measured at 50 feet from the equipment, at all times. While these levels are above existing ambient conditions, they are consistent with typical construction activities and are not anticipated to present significant noise impacts to the community. If construction activities will be conducted during nighttime hours near Class A EDNA properties, a noise variance from the City of Renton would be needed.