Noise and Vibration Assessment

DINGEE BACKBONE PIPELINE REPLACEMENT PROJECTNOISE AND VIBRATION ASSESSMENTOAKLAND, CALIFORNIAOctober 28, 2010♦ ♦ ♦Prepared for:Nat TaylorLamphier-Gregory1944 EmbarcaderoOakland, CA 94606Prepared by:Carrie JanelloMichael S. ThillIllingworth & Rodkin, Inc.505 Petaluma Boulevard SouthPetaluma, CA 94952Job No. 10-086

INTRODUCTIONThis report presents the results of the noise and vibration impact assessment completed for theDingee Backbone Pipeline Replacement Project. The existing Dingee Backbone Pipeline extendsfrom Dingee pumping plant, located in the City of Berkeley to Estates Reservoir located in the Cityof Oakland. The proposed bypass alignment would follow Golden Gate Avenue and BroadwayTerrace, returning to the alignment of the existing backbone pipeline located along Proctor Avenue,Julia Street, and Harbord Avenue. The proposed bypass alignment project would include installationof a new 24-inch to 30-inch diameter pipeline. Additional pipeline improvements, includingrezoning customers on Roble Road and Roble Court in the City of Berkeley from the DingeePressure Zone to the Summit Pressure Zone, would be necessary to maintain customer service. Aregulator would also need to be installed in the Roble Road vicinity to maintain localized customerservice. Another distribution pipeline would be required to replace the 6-inch diameter pipelinelocated along Contra Costa Avenue in Oakland. The pipeline diameters for this ancillary projectwould be 8 inches. Furthermore, new 6-inch to 8-inch diameter pipelines would be necessary toreticulate the proposed backbone pipeline with the existing distribution piping network systems.Connections would occur at the intersections of Golden Gate Avenue with Eustice Avenue, NovaraRoad, Romany Road, Hill Road, Arcadia Avenue, Arbon Path, Buena Vista Avenue, and Erba Path.The noise and vibration impact assessment first presents the fundamentals of noise and vibration forthose who are not familiar with acoustical terminology and concepts. The report then summarizesambient noise conditions in the project vicinity, and provides an evaluation of the potentialsignificance of noise and vibration-related impacts that would result from the project. A list of bestmanagement construction practices is presented to reduce construction noise levels as low asfeasible.SETTINGFundamentals of Environmental NoiseNoise is defined as unwanted sound. Airborne sound is a rapid fluctuation of air pressure above andbelow atmospheric pressure. Sound levels are usually measured and expressed in decibels (dB) with0 dB corresponding roughly to the threshold of hearing. Decibels and other technical terms aredefined in Table 1.Most of the sounds, which we hear in the environment, do not consist of a single frequency, butrather a broad band of frequencies, with each frequency differing in sound level. The intensities ofeach frequency add together to generate a sound. The method commonly used to quantifyenvironmental sounds consists of evaluating all of the frequencies of a sound in accordance with aweighting that reflects the facts that human hearing is less sensitive at low frequencies and extremehigh frequencies than in the frequency mid-range. This is called "A" weighting, and the decibel levelso measured is called the A-weighted sound level (dBA). In practice, the level of a sound source isconveniently measured using a sound level meter that includes an electrical filter corresponding tothe A-weighting curve. Typical A-weighted levels measured in the environment and in industry areshown in Table 2 for different types of noise.Although the A-weighted noise level mayadequately indicate the level of environmental1

noise at any instant in time, community noise levels vary continuously. Most environmental noiseincludes a conglomeration of noise from distant sources, which create a relatively steady backgroundnoise in which no particular source is identifiable. To describe the time-varying character ofenvironmental noise, the statistical noise descriptors, L 01 , L 10 , L 50 , and L 90 , are commonly used.They are the A-weighted noise levels equaled or exceeded during 1%, 10%, 50%, and 90% of astated time period. A single number descriptor called the L eq is also widely used. The L eq is theaverage A-weighted noise level during a stated period of time.In determining the daily level of environmental noise, it is important to account for the difference inresponse of people to daytime and nighttime noises. During the nighttime, exterior backgroundnoises are generally lower than the daytime levels. However, most household noise also decreases atnight and exterior noise becomes very noticeable. Further, most people sleep at night and are verysensitive to noise intrusion. To account for human sensitivity to nighttime noise levels, a descriptor,L dn (day/night average sound level), was developed. The L dn divides the 24-hour day into thedaytime of 7:00 AM to 10:00 PM and the nighttime of 10:00 PM to 7:00 AM. The nighttime noiselevel is weighted 10 dB higher than the daytime noise level. The Community Noise EquivalentLevel (CNEL) is another 24-hour average, which includes both an evening and nighttime weighting.Fundamentals of Groundborne VibrationGround vibration consists of rapidly fluctuating motions or waves with an average motion of zero.Several different methods are typically used to quantify vibration amplitude. One is the Peak ParticleVelocity (PPV) and another is the Root Mean Square (RMS) velocity. The PPV is defined as themaximum instantaneous positive or negative peak of the vibration wave. The RMS velocity isdefined as the average of the squared amplitude of the signal. The PPV and RMS vibration velocityamplitudes are used to evaluate human response to vibration. In this section, a PPV descriptor withunits of mm/sec. or in/sec. is used to evaluate construction generated vibration for building damageand human complaints. Table 3 displays the reactions of people and the effects on buildings thatcontinuous vibration levels produce. The annoyance levels shown in Table 3 should be interpretedwith care since vibration may be found to be annoying at much lower levels than those shown,depending on the level of activity or the sensitivity of the individual. To sensitive individuals,vibrations approaching the threshold of perception can be annoying.Low-level vibrations frequently cause irritating secondary vibration, such as a slight rattling ofwindows, doors or stacked dishes. The rattling sound can give rise to exaggerated vibrationcomplaints, even though there is very little risk of actual structural damage. In high noiseenvironments, which are more prevalent where groundborne vibration approaches perceptible levels,this rattling phenomenon may also be produced by loud airborne environmental noise causinginduced vibration in exterior doors and windows.Construction activities can cause vibration that varies in intensity depending on several factors. Theuse of pile driving and vibratory compaction equipment typically generates the highest constructionrelated ground-borne vibration levels. Because of the impulsive nature of such activities, the use ofthe peak particle velocity descriptor (PPV) has been routinely used to measure and assess groundbornevibration and almost exclusively to assess the potential of vibration to induce structuraldamage and the degree of annoyance for humans.2

The two primary concerns with construction-induced vibration, the potential to damage a structureand the potential to interfere with the enjoyment of life are evaluated against different vibrationlimits. Studies have shown that the threshold of perception for average persons is in the range of 0.2to 0.3 mm/sec (0.008 to 0.012 in/sec), PPV. Human perception to vibration varies with theindividual and is a function of physical setting and the type of vibration. Persons exposed to elevatedambient vibration levels such as people in an urban environment may tolerate a higher vibrationlevel.Structural damage can be classified as cosmetic only, such as minor cracking of building elements, ormay threaten the integrity of the building. Safe vibration limits that can be applied to assess thepotential for damaging a structure vary by researcher and there is no general consensus as to whatamount of vibration may pose a threat for structural damage to the building. Construction-inducedvibration that can be detrimental to the building is very rare and has only been observed in instanceswhere the structure is at a high state of disrepair and the construction activity occurs immediatelyadjacent to the structure.3

Table 1Definitions of Acoustical Terms Used in this ReportTermDecibel, dBSound Pressure LevelDefinitionsA unit describing, the amplitude of sound, equal to 20 times the logarithm to the base10 of the ratio of the pressure of the sound measured to the reference pressure. Thereference pressure for air is 20.Sound pressure is the sound force per unit area, usually expressed in micro Pascals (or20 micro Newtons per square meter), where 1 Pascal is the pressure resulting from aforce of 1 Newton exerted over an area of 1 square meter. The sound pressure level isexpressed in decibels as 20 times the logarithm to the base 10 of the ratio between thepressures exerted by the sound to a reference sound pressure (e.g., 20 micro Pascals).Sound pressure level is the quantity that is directly measured by a sound level meter.Frequency, HzA-Weighted SoundLevel, dBAThe number of complete pressure fluctuations per second above and belowatmospheric pressure. Normal human hearing is between 20 Hz and 20,000 Hz.Infrasonic sound are below 20 Hz and Ultrasonic sounds are above 20,000 Hz.The sound pressure level in decibels as measured on a sound level meter using the A-weighting filter network. The A-weighting filter de-emphasizes the very low andvery high frequency components of the sound in a manner similar to the frequencyresponse of the human ear and correlates well with subjective reactions to noise.Equivalent Noise Level,L eqL max , L minL 01 , L 10 , L 50 , L 90Day/Night Noise Level,L dn or DNLCommunity NoiseEquivalent Level, CNELThe average A-weighted noise level during the measurement period.The maximum and minimum A-weighted noise level during the measurement period.The A-weighted noise levels that are exceeded 1%, 10%, 50%, and 90% of the timeduring the measurement period.The average A-weighted noise level during a 24-hour day, obtained after addition of10 decibels to levels measured in the night between 10:00 pm and 7:00 am.The average A-weighted noise level during a 24-hour day, obtained after addition of 5decibels in the evening from 7:00 pm to 10:00 pm and after addition of 10 decibels tosound levels measured in the night between 10:00 pm and 7:00 am.Ambient Noise LevelThe composite of noise from all sources near and far. The normal or existing level ofenvironmental noise at a given location.IntrusiveThat noise which intrudes over and above the existing ambient noise at a givenlocation. The relative intrusiveness of a sound depends upon its amplitude, duration,frequency, and time of occurrence and tonal or informational content as well as theprevailing ambient noise level.Source: Handbook of Acoustical Measurements and Noise Control, Harris, 19984

Table 2Typical Noise Levels in the EnvironmentCommon Outdoor Activities Noise Level (dBA) Common Indoor Activities110 dBA Rock bandJet fly-over at 1,000 feetGas lawn mower at 3 feet100 dBA90 dBADiesel truck at 50 feet at 50 mphFood blender at 3 feetNoisy urban area, daytime80 dBA Garbage disposal at 3 feetGas lawn mower, 100 feet 70 dBA Vacuum cleaner at 10 feetCommercial areaNormal speech at 3 feetHeavy traffic at 300 feet60 dBALarge business officeQuiet urban daytime 50 dBA Dishwasher in next roomQuiet urban nighttime 40 dBA Theater, large conference roomQuiet suburban nighttime30 dBA LibraryQuiet rural nighttimeBedroom at night, concert hall20 dBABroadcast/recording studio10 dBA0 dBASource: Technical Noise Supplement (TeNS), Caltrans, November 2009.5

Table 3 Reaction of People and Damage to Buildings for Continuous Vibration Levels 1VibrationLevel,PPV (in/sec) Human Reaction Effect on Buildings0.006 to 0.019Threshold of perception,Possibility of intrusionVibration unlikely to cause damage of any type0.08 Vibrations readily perceptibleRecommended upper level of the vibration towhich ruins and ancient monuments should besubjected0.100.200.4 to 0.6Level at which continuousvibrations begin to annoy peopleVibrations annoying to people inbuildingsVibrations consideredunpleasant by people subjectedto continuous vibrationsVirtually no risk of “architectural” damage tonormal buildingsThreshold at which there is a risk of“architectural” damage to normal dwellingssuch as plastered walls or ceilings.Vibration at this level would cause“architectural” damage and possibly minorstructural damage.EXISTING NOISE ENVIRONMENTThe Dingee Backbone Pipeline Replacement project alignment traverses an area comprised primarilyof residential land uses. Local traffic is the primary ambient noise source affecting area residences.A noise monitoring survey was made to quantify ambient noise levels along the project alignment onFriday, July 9, 2010. Short-term noise measurements were made at five locations adjacent tosensitive uses bordering the proposed project alignment: at the intersection of Roble Court and RobleRoad (ST-1); near the dead end of Contra Costa Road (ST-2); at the intersection of BroadwayTerrace and Buena Vista Avenue (ST-3); at the intersection of Proctor Avenue and Agnes Street (ST-4); and at the intersection of Harbord Drive and Amy Drive (ST-5). At each receiver, measurementswere taken over a period of 15-minutes. Figure 1 shows the project alignment, vicinity, and noisemonitoring locations selected during the survey. Table 4 summarizes the noise data collected duringthe survey.ST-1, located on Roble Road at the Roble Court intersection, experienced sparse local traffic duringtesting, including a resident pulling out of a nearby driveway. One jet was noted overhead, and noise1 Transportation Related Earthborne Vibrations (Caltrans Experiences), Technical Advisory, Vibration TAV-02-01-R9601,California Department of Transportation, February 20, 2002.6

Figure 1Noise Measurement Locationsfrom distant traffic along SR 24 was also apparent at the time of testing. Similarly, the local trafficnoise measured along Contra Costa Road at site ST-2 was intermittent, and distant freeways wereaudible. The location of ST-3 was selected to monitor noise levels along Broadway Terrace where itmerges with Golden Gate Avenue, just before the junction. While ST-3 was well shielded fromtraffic noise at the junction, some noise from nearby transformers was captured. Noise levels fromProctor Avenue were measured at site ST-4 where it intersects Agnes Street. Most of the local trafficat ST-4 consisted of automobiles, and two heavy-duty trucks were also monitored. The noise levelsmeasured at ST-5 included sparse local traffic along Harbord Drive and an overhead jet. Byselecting these different sites, the noise environment throughout the Specific Plan Area wascharacterized.Noise measurements were made with a Larson Davis Model 820 Integrating Sound Level Meter set7

at “slow” response. The sound level meter was equipped with a G.R.A.S. Type 40AQ ½ - inchrandom incidence microphone fitted with a windscreen. All instrumentation used meets therequirements of the American National Standards Institute (ANSI) SI.4-1983 for Type 1 use. Thesound level meter was calibrated prior to the noise measurements using a Larson Davis ModelCAL200 acoustical calibrator. The response of the system was checked after each measurementsession and was always found to be within 0.2 dBA.Table 4 Summary of Short-Term Noise Measurement Data – July 9, 2010TimeLocation(Duration)ST-1: Across Roble Road fromRoble Court intersection, ~20 feetfrom roadwayST-2: Front yard of 6300 ContraCosta Road, ~110 yards from deadendST-3: Front yard of 6160Broadway Terrace, ~55 yardsnorth of Broadway junctionST-4: Empty lot at the west-sidecorner of the Agnes-ProctorintersectionST-5: Front yard of 5410 HarbordDrive10:30 a.m.(15 min)11:45 a.m.(15 min)12:30 p.m.(15 min)1:00 p.m.(15 min)1:45 p.m.(15 min)A-Weighted Noise Levels, dBAL eq L max L min L 01 L 10 L 50 L 9053 67 48 62 55 52 5046 62 41 56 47 43 4261 82 41 69 63 53 4653 72 45 65 64 48 4660 74 43 71 65 49 448

IMPACT DISCUSSIONTopic:PotentiallySignificantImpactLess ThanSignificant withMitigationIncorporatedLess ThanSignificantImpact No Impact Not ApplicableNOISE—Would the project:a) Result in exposure of persons to or generation of noise levels inexcess of standards established in the local general plan ornoise ordinance, or applicable standards of other agencies?b) Result in exposure of persons to or generation of excessivegroundborne vibration or groundborne noise levels?c) Result in a substantial permanent increase in ambient noiselevels in the project vicinity above levels existing without theproject?d) Result in a substantial temporary or periodic increase inambient noise levels in the project vicinity above levelsexisting without the project?e) For a project located within an airport land use plan area, or,where such a plan has not been adopted, in an area within twomiles of a public airport or public use airport, would the projectexpose people residing or working in the area to excessivenoise levels?f) For a project located in the vicinity of a private airstrip, wouldthe project expose people residing or working in the projectarea to excessive noise levels?Impact a)Less than Significant Impact. The project may result in exposure of persons to noiselevels in excess of applicable City standards.The project alignment begins in the City of Berkeley and extends southeasterly into the City ofOakland. Applicable standards established by the City of Berkeley and the City of Oakland aresummarized as follows:City of Berkeley Community Noise OrdinanceConstruction noise and vibration in Berkeley is regulated in the Municipal Code as follows:Section 13.40.070, Prohibited Acts7a. Operating or causing the operation of any tools or equipment used in construction,drilling, repair, alteration, or demolition work between weekday hours of seven p.m.and seven a.m., or eight p.m. and nine a.m. on weekends or holidays such that thesound there from creates a noise disturbance across a residential or commercial realproperty line, except for emergency work of public service utilities or by varianceissued by the NCO. (This section shall not apply to the use of domestic power toolsas specified in Section 13.40.070, subsection B.11.)7b. Noise restrictions at affected properties. Where technically and economicallyfeasible, construction activities shall be conducted in such a manner that themaximum sound levels at affected properties will not exceed those listed in thefollowing schedule:9

Mobile Equipment. Maximum sound levels for nonscheduled, intermittent, short-term operation(less than ten days) of mobile equipment:R-1, R-2ResidentialR-3 and aboveMulti-Family Commercial/IndustrialResidentialDaily, 7:00 a.m. to 7:00 75 dBA 80 dBA 85 dBAp.m.Weekends, 9:00 a.m. to8:00 p.m. and legal holidays60 dBA 65 dBA 70 dBAStationary Equipment. Maximum sound levels for repetitively scheduled and relatively long termoperation (period of ten days or more) of stationary equipment:R-1, R-2ResidentialR-3 and aboveMulti-Family Commercial/IndustrialResidentialDaily, 7:00 a.m. to 7:00 p.m. 60 dBA 65 dBA 70 dBAWeekends, 9:00 a.m. to8:00 p.m. and legalholidays50 dBA 55 dBA 60 dBA8. Vibration. Operating or permitting the operation of any device that creates a vibrationwhich annoys or disturbs at least two or more reasonable persons of normalsensitiveness who reside in separate residences (including apartments andcondominiums) at or beyond the property boundary of the source if on privateproperty or at least one hundred fifty feet (forty-six meters) from the source if on apublic space or public right-of-way.City of Oakland Planning CodeConstruction noise in Oakland is regulated in the Planning Code as follows:Section 17.120, Performance StandardsG. Temporary Construction or Demolition Which Exceed the Following Noise LevelStandards.1. The daytime noise level received by any residential, commercial, or industrial land usewhich is produced by any nonscheduled, intermittent, short-term construction ordemolition operation (less than ten (10) days) or by any repetitively scheduled andrelatively long-term construction or demolition operation (ten (10) days or more) shallnot exceed the maximum allowable receiving noise levels described in Table 17.120.04.Formatted: Numbered + Level: 1 +Numbering Style: A, B, C, … + Start at: 7 +Alignment: Left + Aligned at: 0.5" + Tab after:0.75" + Indent at: 0.75"Table 17.120.04 (Table 5) establishes the maximum allowable receiving noise levels:Table 5 Table 17.120.04, Maximum Allowable Receiving Noise Level Standards, dBA10

Daily 7 a.m. to 7 p.m.Weekends 9 a.m. to 8 p.m.Short-Term OperationResidential 80 65Commercial, Industrial 85 70Long-Term OperationResidential 65 55Commercial, Industrial 70 602. The nighttime noise level received by any land use and produced by any construction ordemolition activity between weekday hours of seven (7) p.m. and seven (7) a.m. or betweeneight (8) p.m. and nine (9) a.m. on weekends and federal holidays shall not exceed theapplicable nighttime noise level standards outlined in this section.Maximum instantaneous noise levels resulting from the noisiest construction activities proposed forthe project (i.e., jack hammering) would be approximately 89 dBA L max at 50 feet. Maximuminstantaneous noise levels from other required equipment would typically be less than 85 dBA L maxat 50 feet. Maximum noise levels are calculated to exceed the City of Berkeley Community NoiseOrdinance limit of 60 dBA L max for long-term operations (period of 10 days or more) whenmaximum noise events occur within 1,400 feet of sensitive land uses with direct line of sight to theseactivities. Maximum noise levels would potentially violate the Berkeley Community NoiseOrdinance limits over a period ranging from 35 to 47 days.Maximum noise levels would exceed the City of Oakland’s Planning Code limit of 65 dBA L max forlong-term operations (period of 10 days or more) when maximum noise events occur within 800 feetof sensitive land uses having direct line of sight to the work area. Maximum noise levels wouldpotentially violate the Oakland’s Planning Code limit over a period ranging from 20 to 26 days.Construction noise resulting from the project would be mitigated by limiting activities to theallowable hours established by the City of Berkeley and City of Oakland and by implementing bestmanagement construction practices as discussed under Impact d). By following the bestmanagement construction practices discussed under Impact d), the impact would be reduced to a lessthan significant level.Impact b)Less than Significant Impact. The project would not result in exposure of persons toor generation of excessive ground-borne vibration levels.There are no local, state, or federal vibration impact criteria that are applicable to this project. TheCalifornia Department of Transportation uses a vibration limit of 12.7 mm/sec (0.5 in/sec), PPV forbuildings structurally sound and designed to modern engineering standards. A conservative vibrationlimit of 5 mm/sec (0.2 in/sec), PPV has been used for buildings that are found to be structurallysound but structural damage is a major concern. For historic buildings or buildings that aredocumented to be structurally weakened, a conservative limit of 2 mm/sec (0.08 in/sec), PPV is often11

used to provide the highest level of protection. All of these limits have been used successfully, andcompliance to these limits has not been known to result in appreciable structural damage. Allvibration limits referred to herein apply on the ground level and take into account the response ofstructural elements (i.e. walls and floors) to ground-borne excitation.The majority of project construction activities would employ open-trench construction methods toinstall the new backbone pipeline, distribution lines, cross-connections, and customer serviceconnections. After the pipelines are installed, the trench and pavement would be restored. Finally,the existing pipelines and connections would be abandoned.Activities with the potential of generating perceptible vibration levels would include the removal ofpavement and soil, shoring, and the compacting of backfill after the new pipeline is installed. Theproposed project would, at times, bring construction activities within about 25 feet of sensitive landuses along the project alignment. Table 6 summarizes typical vibration levels associated withvarying pieces of construction equipment at a distance of 25 feet.Equipment anticipated during project construction would include: backhoes, excavators, cranes,dump trucks, front end loaders, asphalt pavement grinders, boiler trucks, bypass pipes, asphaltpavers, concrete trucks and various passenger vehicles. Neither vibratory or impact pile driving areproposed as part of the construction of the project.A review of the proposed equipment and the vibration level data provided in Table 5 indicates thatvibration levels generated by the majority of proposed equipment would be equal to or below the 0.2in/sec PPV criteria used to assess the potential for cosmetic damage to buildings of normalconventional construction. Vibration levels from dropping heavy equipment (clam shovel drop) orthe operation of a vibratory roller at a distance of 25 feet could slightly exceed the 0.2 in/sec PPVcriteria. Theoretically, these potential exceedances could be up to one one-hundredth of an inch persecond PPV (0.01 in/sec PPV). However, at a distance of 26 feet, the levels are calculated to be lessthan the 0.2 in/sec PPV criteria. Sporadic events such as dropping of heavy objects, and the use ofvibratory rollers within 25 feet of residences should be avoided to the extent possible. The impactresulting from the project would be considered less-than-significant as vibration levels would notexceed the 0.2 in/sec PPV criteria established to evaluate the risk for cosmetic or structural damageto buildings. Vibration levels generated by construction activities would be perceptible indoors andmay be considered annoying. However, planned construction hours are during the daytime, limitingthe possibility of annoyance during typical periods of sleep or rest, and would only affect a particularresidence for a brief period of time as construction activities occur in areas immediately adjoining theresidence.12

Table 6 Vibration Source Levels for Construction Equipment 2EquipmentPPV at 25 ft. (in/sec)Clam shovel drop 0.202Hydromill (slurry wall) in soil 0.008in rock 0.017Vibratory Roller 0.210Hoe Ram 0.089Large bulldozer 0.089Caisson drilling 0.089Loaded trucks 0.076Jackhammer 0.035Small bulldozer 0.003Impact c)Impact d)Not applicable. The operation of the project would not result in measurable noiselevels above ground. Therefore, this significance criterion is not applicable to theproposed project.Less than Significant Impact. The project would not result in a substantialtemporary or periodic increase in ambient noise levels in the project vicinity abovelevels existing without the project.Noise levels at sensitive receivers adjacent to the pipeline alignment would increase during theconstruction period when activities are located in close proximity. Pipeline installation would occurat a rate of approximately 60 to 80 linear feet per day, therefore, construction noise levels would onlybe substantially increased over a short period of time. Construction activities would only occurduring the daytime hours only; no evening or nighttime work is proposed.Noise impacts from project construction activities are a function of the level of noise generated byindividual pieces of construction equipment, the amount of equipment operating at any given time,the distance and sensitivities of nearby land uses, the presence of noise barriers or other structuresthat provide acoustical shielding, and the timing and duration of the noise-generating activities.Where noise from construction activities exceeds 60 dBA L eq and exceeds the ambient noiseenvironment by at least 5 dBA L eq at noise-sensitive residential uses in the project vicinity for aperiod of more than one construction season, the impact would be considered significant.Construction noise would primarily consist of the operation of vehicles and equipment duringpavement removal, excavation, pipeline installation, backfill operations, and the repaving of theportion of the street disturbed by the project. The highest construction noise levels would begenerated during trenching operations. Table 7 presents the typical range of hourly average noiselevels generated by different phases of construction measured at a distance of 50 feet. Hourlyaverage noise levels generated by public works-type projects at a distance of 50 feet from the centerof a busy construction site typically range from 79 dBA to 88 dBA L eq .2 Transit Noise and Vibration Impact Assessment, United States Department of Transportation, Office of Planning andEnvironment, Federal Transit Administration, May 2006.13

Table 7Typical Range of Noise Levels at 50 Feet from Construction Sites(dBA L eq )IndustrialParking Garage,ReligiousAmusement &Recreations,Store, ServicePublic WorksRoads &Highways,Sewers, andTrenchesOffice Building,Hotel, Hospital,DomesticHousingSchool, PublicWorksStationI II I II I II I II83 83 84 84 84 83 84 84GroundClearingExcavation 88 75 89 79 89 71 88 78Foundations 81 81 78 78 77 77 88 88Erection 81 65 87 75 84 72 79 78Finishing 88 72 89 75 89 74 84 84I - All pertinent equipment present at site.II - Minimum required equipment present at site.Source: United States Environmental Protection Agency, 1973, Legal Compilation on Noise, Vol. 1, p. 2-104.During construction activities, maximum instantaneous noise levels would vary depending on thespecific pieces of equipment operating on-site. Large pieces of earth-moving equipment, such asexcavators or front-end loaders, generate maximum noise levels of 85 to 90 dBA at a 50-footdistance. These noise levels drop off at a rate of about 6 dBA per doubling of distance between thesource and receptor. Shielding provided by barriers or structures can provide an additional 5 to 10dBA noise reduction at distant receivers.Representative sound levels for the most common types of construction equipment and usage factors,contained in FHWA’s Roadway Construction Noise Model, were used to calculate noise levelsrelated to proposed construction activities. The cumulative noise level would assume all pieces ofconstruction equipment were operating simultaneously at the site and represents a conservativeworst-case prediction of site construction noise levels during each construction phase. These data aresummarized in Table 8.The installation of pipelines (pavement removal, excavation, pipeline installation, compactingbackfill, and repaving the roadway) would result in average noise levels of approximately 86 dBAL eq at a distance of 50 feet. Maximum instantaneous noise levels during this phase would reach 89dBA L max at a distance of 50 feet assuming that a jack hammer would be required to remove theexisting pavement. The calculated hourly average noise level of 86 dBA L eq would exceed ambientnoise levels (plus 5 dBA) at the receivers by approximately 20 to 35 dBA L eq , which is a substantialincrease in noise. Pipeline installation would occur at a rate of approximately 60 to 80 linear feet perday. Therefore, construction noise levels would only exceed the significance criterion of 60 dBA L eqover a relatively short period of time (5 to 6 weeks). This would be considered a less than significantnoise impact recognizing the relatively short duration of project construction activities.14

Table 8Construction Noise Levels During Installation of Pipelines at 50 FeetReceiverMaximumInstantaneous NoiseLevel, L maxAverage NoiseLevel, L eqDaytime Ambient,L eqNoise Increase aboveAmbient + 5 dBAST-1 89 dBA 86 dBA 53 dBA 28 dBAST-2 89 dBA 86 dBA 46 dBA 35 dBAST-3 89 dBA 86 dBA 61 dBA 20 dBAST-4 89 dBA 86 dBA 53 dBA 28 dBAST-5 89 dBA 86 dBA 60 dBA 21 dBAThe project would also result in a maximum of 59 one-way trips per day and a maximum of 4 trucksand 13 vehicles during any hour. Worker trips would primarily be concentrated during the morningand evening commute periods and at lunch. A credible worst-case scenario was developed tocalculate the increase in traffic noise levels expected as a result of project construction trips. Thisscenario assumed that during the worst traffic hour, there would be up to 13 worker trips and 4 trucktrips traveling along roadways serving the site. The hourly average noise level resulting from thesetrips was calculated to be 56 dBA L eq at 50 feet from the roadway center. Project construction tripswould generate noise levels approximately 3 dBA L eq above ambient noise levels at receivers ST-1and ST-4, approximately 10 dBA L eq above ambient noise levels at ST-2, and 4 to 5 dBA L eq belowambient noise levels measured at Sites ST-3 and ST-5.The following available controls are assumed to be included in the project to reduce constructionnoise levels as low as practical. In Oakland, the inclusion of these controls is assumed to reduce theimpact from project construction to less-than-significant levels. Recognizing that projectconstruction trips would coincide with construction equipment noise levels generated in the vicinity,and that the anticipated noise levels would exceed the significance criterion over a relatively shortduration, the impact would also be considered less than significant. All City of Oakland StandardConditions of Approval regarding noise control measures must be implemented at the project site atall times:Construction Related Noise Control During All Construction ActivitiesDays/Hours of Construction Operation - Ongoing throughout demolition, grading, and/orconstructionThe project applicant shall require construction contractors to limit standard construction activities asrequired by the City Public Works Department.15

Major Project Cases:a) Such activities are limited to between 7:00 a.m. and 7:00 p.m. Monday through Friday,with pile driving and/or other extreme noise generating activities greater than 90 dBAlimited to between 8:00 a.m. and 4:00 p.m. Monday through Friday.b) Any construction activity proposed to occur outside of the standard hours of 7:00 am to7:00 pm Monday through Friday for special activities (such as concrete pouring whichmay require more continuous amounts of time) shall be evaluated on a case by case basis,with criteria including the proximity of residential uses and a consideration of resident’spreferences for whether the activity is acceptable if the overall duration of construction isshortened and such construction activities shall only be allowed with the prior writtenauthorization of the Building Services Division.c) Construction activity shall not occur on Saturdays, with the following possibleexceptions:I. Prior to the building being enclosed, requests for Saturday construction forspecial activities (such as concrete pouring which may require more continuousamounts of time), shall be evaluated on a case by case basis, with criteriaincluding the proximity of residential uses and a consideration of resident’spreferences for whether the activity is acceptable if the overall duration ofconstruction is shortened. Such construction activities shall only be allowed onSaturdays with the prior written authorization of the Building Services Division.No extreme noise generating activities shall be allowed on Saturdays, with noexceptions.Formatted: Numbered + Level: 1 +Numbering Style: a, b, c, … + Start at: 3 +Alignment: Left + Aligned at: 0.5" + Tab after:0.75" + Indent at: 0.75"Formatted: Numbered + Level: 1 +Numbering Style: I, II, III, … + Start at: 1 +Alignment: Left + Aligned at: 0.75" + Tabafter: 1.25" + Indent at: 1.25"II.After the building is enclosed, requests for Saturday construction activities shallonly be allowed on Saturdays with the prior written authorization of the BuildingServices Division, and only then within the interior of the building with the doorsand windows closed.Formatted: Numbered + Level: 1 +Numbering Style: I, II, III, … + Start at: 1 +Alignment: Left + Aligned at: 0.75" + Tabafter: 1.25" + Indent at: 1.25"d) No extreme noise-generating activities shall be allowed on Saturdays, with no exceptions.e) No construction activity shall take place on Sunday or Federal holidays.f) For clarification, construction activities include but are not limited to: truck idling,moving equipment (including trucks, elevators, etc) or materials, deliveries, andconstruction meetings held on-site in a non-enclosed area.Noise Control - Ongoing Throughout Demolition, Grading, and/or ConstructionTo reduce noise impacts due to construction, the project applicant shall require constructioncontractors to implement a site-specific noise reduction program, subject to city review and approval,which includes the following measures:a) Equipment and trucks used for project construction shall utilize the bestFormatted: Numbered + Level: 1 +Numbering Style: a, b, c, … + Start at: 3 +Alignment: Left + Aligned at: 0.5" + Tab after:0.75" + Indent at: 0.75"Formatted: Numbered + Level: 1 +Numbering Style: a, b, c, … + Start at: 3 +Alignment: Left + Aligned at: 0.5" + Tab after:0.75" + Indent at: 0.75"Formatted: Numbered + Level: 1 +Numbering Style: a, b, c, … + Start at: 3 +Alignment: Left + Aligned at: 0.5" + Tab after:0.75" + Indent at: 0.75"Formatted: Numbered + Level: 2 +Numbering Style: a, b, c, … + Start at: 1 +Alignment: Left + Aligned at: 1.25" + Tabafter: 1.5" + Indent at: 1.5"16

available noise control techniques (e.g., improved mufflers, equipmentredesign, use of intake silencers, ducts, engine enclosures and acousticallyattenuatingshields or shrouds, wherever feasible).b) Impact tools (e.g., jack hammers, pavement breakers, and rock drills) used forproject construction shall be hydraulically or electrically powered whereverpossible to avoid noise associated with compressed air exhaust frompneumatically powered tools. However, where use of pneumatic tools isunavoidable, an exhaust muffler on the compressed air exhaust shall be used;this muffler can lower noise levels from the exhaust by up to about 10 dBA.External jackets on the tools themselves shall be used where feasible, and thiscould achieve a reduction of 5 dBA. Quieter procedures shall be used, such asdrills rather than impact equipment, whenever feasible.c) Stationary noise sources shall be located as far from adjacent receptors aspossible, and they shall be muffled and enclosed within temporary sheds,incorporate insulation barriers, or other measures to the extent feasible.d) If feasible, the noisiest phases of construction (such as pile driving) shall belimited to less than 10 days at a time.Formatted: Numbered + Level: 2 +Numbering Style: a, b, c, … + Start at: 1 +Alignment: Left + Aligned at: 1.25" + Tabafter: 1.5" + Indent at: 1.5"Noise Complaint Procedures - Ongoing Throughout Demolition, Grading, and/or ConstructionPrior to the issuance of each building permit, along with the submission of construction documents,the project applicant shall submit to the City Building Department a list of measures to respond toand track complaints pertaining to construction noise. These measures shall include:a) A procedure and phone numbers for notifying the City Building Services Divisionstaff and Oakland Police Department; (during regular construction hours and offhours);b) A sign posted on-site pertaining with permitted construction days and hours andcomplaint procedures and who to notify in the event of a problem. The sign shall alsoinclude a listing of both the City and construction contractor’s telephone numbers(during regular construction hours and off-hours);c) The designation of an on-site construction complaint and enforcement manager forthe project;d) Notification of neighbors and occupants within 300 feet of the project constructionarea at least 30 days in advance of pile-driving activities about the estimated durationof the activity; ande) A preconstruction meeting shall be held with the job inspectors and the generalcontractor/on-site project manager to confirm that noise mitigation and practices(including construction hours, neighborhood notification, posted signs, etc.) arecompleted.Formatted: Numbered + Level: 1 +Numbering Style: a, b, c, … + Start at: 1 +Alignment: Left + Aligned at: 0.75" + Tabafter: 1" + Indent at: 1"With the implementation of the above feasible noise control measures, and recognizing that17

construction activities would be of relatively short duration, the impact would be less thansignificant.Impact e)Impact f)Not applicable. The project is not located within an airport land use plan area orwithin two miles of a public airport. This significance criterion is not applicable tothe proposed project.Not applicable. The project site is not located within the vicinity of a privateairstrip. This significance criterion is not applicable to the proposed project.18