Noise Monitoring 2009 Springbank Airport

Transcription

1 Noise Monitoring 2009 Springbank Airport June 30, 2010

2 EXECUTIVE SUMMARY The (the Authority) conducted a noise monitoring survey for the operations at Springbank Airport (YBW). In June 2009, supplementary noise monitoring was requested by local residents, via the Springbank Airport Community Noise Consultative Committee (SACNCC), which resulted in the Authority revisiting the monitoring that had been conducted in the past. The objective of this monitoring study was to focus on ambient sound levels within the Springbank area those residential dwellings under flight paths and circuit training areas. The study s function was only to obtain data and understand the sound environment in the vicinity of YBW and draw comparisons to the data from previous years. The noise levels at five sites, in the vicinity of the YBW, were measured continuously for a period of 24 hours each. From August 16 27, 2009 the Sound Level Meter (SLM) sampled the noise environment and generated noise level histories and statistics. This data includes all other noise sources in the community, as well as noise emitted from aircraft. The noise histories are useful when illustrating the variation of average noise levels throughout the day and night, as well as indicating the range of noise levels experienced at various times of the day. The Authority had conducted previous noise monitoring in the community in 1998 and Environmental noise analyses at selected locations are presented to characterize typical equivalent noise levels and typical background noise level at selected sites adjacent to YBW. This report provides a summary of sound data collected by a portable noise monitor (Larson & Davis) from all monitoring locations. During the monitoring study, just over 120 hours of continuous sound data was collected. The data gathered for this study is more voluminous than previous studies in 1999 and In 1998 and 1999, LAeq(1) was the only parameter recorded. The 2009 study looked at these supplementary metrics and these are as follows. LAeq (1 hour) LAeq (24 hour) LAeq (8 hour) Night time: 2300 and 0700 hours; LAeq (16 hour) Day time: 0700 and 2300 hours; LAmax (instantaneous value) ; LAmin (instantaneous value); LA5; and LA90. The LAeq hourly values are consistent with the previous noise monitoring that has occurred at YBW and are comparable to the 1999 and 1998 monitoring work. Other metrics used for this study (LAeq(24); LAeq(8); LAeq(16); LAmax; LAmin; LA5; and LA90 are newer and these values will not be comparable to previous work, but they do provide a baseline for future comparison. A comparison between data gathered at the monitoring locations was be compared to Alberta s EUB Directive 038: Noise Control (the Directive ). Because YBW does not have set maximum noise targets in Canada noise parameters are set through the aircraft certification process it is valuable to compare YBW community noise levels to set standards that exist in industry. Thus, a comparison between YBW community hourly LAeq and required oil and gas facilities noise and the noise level limits imposed by the province of Alberta (some of the most rigorous in North America). The Directive speaks to both night time noise and day time noise. All values were below oil and gas industry standards. In the study it was found that those dwellings further away from other significant sound sources (roads) in the area had lower LAeq values. Location 2 residence had the quietest nighttime LAeq value (LAeq (8)) but Location 3 had the lowest 24 and 1 hour LAeq values. This is consistent with its location away from roads as well as a lack of other noise sources, such as lawn mowers and tractors. This monitoring project provides further info into the soundscape within the proximity of YBW. Springbank Airport Noise Study 2009 Page i

3 TABLE OF CONTENTS Page No. EXECUTIVE SUMMARY... i 1.0 INTRODUCTION Objectives Background YBW: Type of Aircraft Movements Circuit Training Fixed Wing Circuits Rotary Wing Circuits Requirement for Baseline Monitoring Outline of Document REGULATIONS AND POLICIES GUIDING AVIATION IN CANADA International Standards Aeronautics Act Canadian Aviation Regulations CAR Minimum altitudes and Distances Policies Engine Run up Policy Other Standards NOISE COMMUNITY CONCEPTS AND TERMINOLOGY What is Sound? Sound Propagation Noise Metrics Terminology Decibels (db) Loudness and the Decibel Scale Equivalent Sound Level (LAeq) LAmax and LAmin Exceedance Level (L AN ) Measuring Community Noise Factors that Influence Noise Propagation Typical Range of Noise Exposures in the Community Aircraft Noise Impacts and Impact Thresholds Types of Community Noise Impact caused by Aircraft Noise Annoyance Speech Interference BUILDING CODES AND SOUND REDUCTION Walls Windows Roof NOISE MONITORING METHODOLOGY Ambient Noise Monitoring Equipment and Procedures General Approach to Ambient Noise Monitoring Instrumentation Set up and Calibration Existing Ambient Noise Sources Ambient Noise Monitoring Locations Location Springbank Airport Noise Study 2009 Page ii

4 5.3.2 Location Location Location Location General Flight Path of Aircraft over YBW MONITORING RESULTS Monitoring Metrics Noise Level from Monitoring Locations Exceedance Noise Levels Cumulative Noise Values for Each Monitoring Location Location Location Location Location Location Comparison of Data to EUB Directive 038 Noise Control CONCLUSIONS LITERATURE CITED Springbank Airport Noise Study 2009 Page iii

5 LIST OF TABLES Table 1 Basic sound levels for night time ( hrs) and daytime ( hrs)* (EUB 2007)... 8 Table 2 Summary of Noise Measurement Locations Table 3 Summary of Noise Measurement at Location Table 4 Summary of Noise Measurement at the Location Table 5 Summary of Noise Measurement at Location Table 6 Summary of Noise Measurement at Location Table 7 Summary of Noise Measurement at Location Table 8 Comparison of Directive parameters with day and night LAeq values recorded at each monitoring location LIST OF FIGURES Figure 1 Aircraft movements at YBW Figure 2 Springbank Airport Figure 3 Aircraft traffic types at YBW... 4 Figure 4 Circuit training pattern... 5 Figure 5 Typical sound levels in A weighted decibels (dba) (City of Vancouver 2005) Figure 6 Larson & Davis Hand held Analyzer 2250 (SLM) Figure 7 YBW and monitoring locations in Figure 8 Hourly LAeq, Lmax and Lmin Values over a 24 hour period: Location Figure 9 Hourly LAeq, Lmax and Lmin Values over a 24 hour period: Location Figure 10 Hourly LAeq, Lmax and Lmin Values over a 24 hour period: Location Figure 11 Hourly LAeq, Lmax and Lmin Values over a 24 hour period: Location Figure 12 Hourly LAeq, Lmax and Lmin Values over a 24 hour period: Location Figure 13 Noise exceedance levels at each monitoring location at YBW Figure 14 SLM set up and location at Location Figure 15 Location 1 LAeq (1) values 1998, 1999 and 2009 compared Figure 16 SLM set up and location at Location Figure17 Location 2 LAeq values Figure 18 SLM set up and location at Location Figure19 Location 3 LAeq values 1998, 1999 and 2009 compared Figure 20 SLM set up and location at Location Figure 21 Location 4 LAeq values 1998, 1999 and 2009 compared Figure 22 SLM set up and location at Location Figure 23 Location 5 LAeq values 1998, 1999 and 2009 compared LIST OF APPENDICES Appendix A Appendix B Springbank Airport Noise Study 2009 Page iv

6 LIST OF ABBREVIATIONS AFTEMS ASL AVPA db dba DNL EUB FICAN FICON Hz ICAO ISO LAeq LAmax LAmin NEF NRC OITC OSB SACNCC SLM STC US EPA YBW Aircraft Flight Tracking Environmental Management System Above Sea Level Airport Vicinity Protection Area Decibel A weighted decibels Day Night Average Sound Level Energy and Utility Board Federal Interagency Committee on Aviation Noise Federal Interagency Committee on Noise Hertz International Civil Aviation Organization International Organization for Standardization Equivalent Sound Level Maximum noise level Minimum noise level Noise Exposure Forecast National Research Council Outdoor Indoor Transmission Class Oriented Strand Board Springbank Airport Community Noise Consultative Committee Sound Level Meter Sound Transmission Class U.S. Environmental Protection Agency Springbank Airport Springbank Airport Noise Study 2009 Page v

7 1.0 INTRODUCTION Air traffic is noisy and living close to an airport is not always ideal. The noise created by aircraft landing, taking off and overflying communities is an issue for communities in close proximity to airports. The (the Authority) conducted a noise monitoring survey for the operations at Springbank Airport. The sound levels at five sites in the vicinity of the Springbank Airport (YBW) were measured continuously for a period of 24 hours each. The Authority had conducted previous noise monitoring in the community in 1998 and In June 2009, supplementary noise monitoring was requested by a local resident, which resulted in the Authority to revisit the monitoring that has been conducted in the past. The study s function is only to obtain data and understand the sound environment in the vicinity of YBW. 1.1 Objectives The objectives of this study are to build on the existing database collected in 1998 and 1999 to measure the ambient noise within the community of Springbank and compare it to the previous works. The study will follow the same methodology as in previous monitoring work, however, there was the addition of supplemental noise metrics to further convey noise levels. This will create a level of consistency in the analysis of community noise levels between the three studies. The study s function is only to obtain data. 1.2 Background YBW, located 10 kilometres to the west of the City of Calgary, in Rocky View County, is a reliever airport for small aircraft traffic to the Calgary International Airport. The airport is operated by The (The Authority) under 60 year lease from the federal government. YBW had over 203,000 movements in 2008 (Figure 1). Figure 1 Aircraft movements at YBW Springbank Airport Noise Study 2009 Page 1

8 The airport is classified as a Local Commercial (Satellite) Sub Class V Airport by Transport Canada. The airport is equipped with two paved runways with designations (3400 x 100 ) and (5000 x 98 ), as well as three taxiways, two uncontrolled maneuvering surfaces, and a common use apron (see Figure 2). YBW provides a base for both private and commercial light aircraft operations, including pilot training, charter services and recreational flying. The majority of the aviation activity is associated with flight training and rotary aircraft operations. Anecdotal information suggests that this activity accounts for about 80% of the total aircraft movements at YBW. In 1994, the Federal government first introduced the National Airports Policy, which set the stage for the preliminary transfer of YBW to The Authority. The official transfer took place on October 1, At that time, Transport Canada's role changed from airport owner and operator to that of owner and landlord with The Authority taking over full operational responsibilities. One of The Authority's first responsibilities, prior to the transfer of YBW, was to develop a baseline study on aircraft noise levels in the community of Springbank. The establishment of baseline noise data coupled with additional noise measurements over the years has allowed The Authority to compare noise levels over time to determine any significant changes. The 2009 monitoring data will continue to provide analytical information for the future management decisions on the operation of the airport YBW: Type of Aircraft Movements Air traffic movements at YBW, have decreased significantly from 2000 to In 2000, aircraft movements were over 238,000 in comparison to 2009 with just over 180,000 a 24% decrease. YBW s aircraft movements can be broken down into four discernible traffic types: itinerant, training, shuttle and helicopter. Figure 3 is a graphical depiction of the traffic types and how NAV CANADA manages the airspace around YBW. An overview of this activity is described below. Itinerant Traffic (shown as solid red lines): involves aircraft which come into Springbank from another location and land, or take off at Springbank. An itinerant corridor exists in a north south direction, in line with runway as shown in Figure 3. Itinerant activity also includes the air traffic which shuttles to and from the training area located north and west of the Town of Cochrane. This traffic is depicted by the solid red arc. Aircraft practicing instrument approaches also fall into this category. Training Traffic (dashed red lines): involves aircraft which fly around the airport in what is known as a training circuit. They do not leave the local Air Traffic Control Zone. The two training circuits at Springbank take on rectangular shapes as shown on Figure 3. The base of each rectangular area is coincident with the centre lines of the two runways at Springbank. Only one circuit is in use at any given time, depending on wind conditions. There can be as many as five aircraft in a training circuit at any one time. Shuttle Traffic (solid blue lines): involves aircraft flying between the Calgary International Airport and YBW. Helicopter Training Traffic (solid green lines): These are the training circuits used by helicopters. Like the training circuit for fixed wing aircraft, only one circuit is in use at any given time. The circuit in use is dependent upon which circuit is being used for fixed wing activities. For example, when runway is being used for fixed wing training, helicopter training utilizes the circuit at the threshold of Runway 25. Alberta Forestry has operated out of YBW since 2006 (and only in the summer months) for the purpose of fighting forest fires in southern Alberta. Their movements are primarily off of Runway and they operate propeller aircraft over 5,700 kilograms. Their number movements are dependent on the fire season and are not at all predictable. Springbank Airport Noise Study 2009 Page 2

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11 Chapter 3 1 jet aircraft have been allowed to operate at YBW since There was trepidation by some residences for the inclusion of jet operations at YBW; however, by the end of 2009, jet operations made up less than 0.3% of all operations a minimal component of the fleet mix at YBW Circuit Training Fixed Wing Circuits All fixed wing circuits at the airport follow a standard rectangular pattern. A rectangular circuit consists of a crosswind leg, downwind leg, base leg, and final leg. Once a pilot departs the runway they will climb to 500 AGL before turning 90º for the crosswind leg. They will stay on the crosswind for 1 2 miles before turning 90º for the downwind leg. The downwind leg is flown parallel to the runway and can vary in length. Once the downwind has been flown, the pilot will turn 90º for base; the base leg is 1 2 miles or whatever is required to line up with the runway and then the pilot will turn 90º for final. Aircraft should be in direct line with the runway (Figure 4). Figure 4 Circuit training pattern All circuits at Springbank are flown in this pattern with different directional turns: Runways 07(eastbound) and 34(Northbound), are flown with left hand turns. Runways 16(Southbound) and 25(Westbound) are flown with right hand turns. 1 This is the International Civil Aviation Organization system used to determine and certify the noise level of an aircraft based on weight, number of engines and, occasionally, its passenger capacity. Aircraft noise levels are certified as Chapter 2, 3, or 4. Chapter 2 includes aircraft such as the B 727, B , and the DC 9. Chapter 2 aircraft were required by law to be modified with hush kits to meet Chapter 3 noise levels or phased out of service by April 1, Chapter 3 aircraft are on average about 10 decibels (db) quieter than a comparably sized Chapter 2 aircraft. These aircraft include the Boeing , 757 and 767; the Airbus 320; and the MD 80/90. Springbank Airport Noise Study 2009 Page 5

12 This ensures circuit traffic using 16/34 always remain west of the runway while circuit traffic using 07/25 remain north of the runway. As mentioned above, the downwind leg can vary in length; normal downwind legs are approximately 3 miles but Runway 16/34 can be extended as far as the Bow River to the north (Runway 16) and the Elbow River to the south (RWY 34) and Runway 07/25 can be extended as far east as Bearspaw Dam (Runway 25) and as far west as Range Road Rotary Wing Circuits Rotary wing aircraft are integrated into the normal flow of a fixed wing traffic circuit. Helicopters must however conform to the traffic patterns (size and speed). If unable, helicopters are to be moved to locations that have minimal impact on traffic flows; this includes circuiting to the threshold of an inactive runway or circuiting inside and below the active fixed wing circuit. When Runway 16 is active, helicopters will do left hand circuits southbound from the threshold of 25. When Runway 34 is active they will do right hand circuits northbound from the threshold of 25. When Runway 07 is active they will do right hand circuits eastbound from the threshold of 34 or left hand circuits eastbound from Taxiway A2 or the threshold of Runway 16 but not above 4500 ASL. When Runway 25 is active they have two options: Left hand circuits westbound from the threshold of 34 or right hand circuits westbound from Taxiway A2 or the threshold of 16 but not above 4500 ASL. 1.3 Requirement for Baseline Monitoring In response to community noise concerns over the years, the Authority, conducted noise monitoring studies which developed baseline sound levels in the community. The establishment of a database allows the Authority to compare sound levels over time in order to determine any significant changes. The data captured in 2009 will continue to play an important role in future noise management decisions on airport operations. 1.4 Outline of Document This document is divided into six sections as outlined below. Section 2 discusses the regulations and policies guiding aviation. Section 3 explains noise concepts, terminology of community noise, its measurement and perception, as well as the specific nature of aircraft noise and its potential impacts on communities. Section 4 explains building codes and sound reduction initiatives. Section 5 describes the methodology used for the noise study. Section 6 results and discussion of noise monitoring study. Section 7 is the conclusions to the study. Springbank Airport Noise Study 2009 Page 6

13 2.0 REGULATIONS AND POLICIES GUIDING AVIATION IN CANADA Regulations and policies dealing with noise management exist at various levels from international standards set by the International Civil Aviation Organization (ICAO) to local Airport Authority policies. The responsibility for noise management at YYC does lie with The Authority; however, The Authority has no regulatory authority or enforcement powers for aeronautical regulations. Enforcement is administered by Transport Canada. International standards and operating procedures for aircraft certification and operations are developed by working committees of ICAO and referenced in the legislation of the member countries. In Canada, the Aeronautics Act and the Canadian Aviation Regulations (CAR) reference ICAO standards and procedures relating to noise certification and aircraft operations. Appendix I provides a brief synopsis of the regulations and guidelines governing aeronautical noise in Canada and in Alberta. 2.1 International Standards Because air travel is international in scope, the ICAO was formed to develop acceptable standards for the aviation industry. Noise certification standards were developed to limit noise at the source the aircraft, which are addressed within the CAR (mentioned above). Noise certification is accomplished by measuring the noise of aircraft at maximum take off weight at three separate positions on departure, on arrival and sideline noise. Noise certification is conducted for propeller aircraft. The latest certification standard developed and instituted by ICAO was in Thus all propeller aircraft built after 1988 are certified to this standard. All aircraft that fly in Canada are certified to operate at YBW and meet the noise certification that Canada is obliged to implement as a member state of ICAO. 2.2 Aeronautics Act The Aeronautics Act (RS, 1985, c. A 2), a federal statute, gives power to the Minister of Transport to make regulations regarding noise emanating from aircraft and aerodromes (Section 4.9(f)). The Act also states that other standards, procedures or specifications can be incorporated by reference such as the ICAO Annex 16 Chapters 2, Chapter 3 and Chapter 4, which specify noise certification standards for aircraft. 2.3 Canadian Aviation Regulations The Canadian Aviation Regulations (CAR) is a compilation of regulatory requirements governing aeronautics in Canada and is designed to enhance safety and competitiveness of the Canadian aviation industry. The CAR address issues ranging from international standards for aircraft noise and air emissions, prescribed minimum aircraft altitudes, noise abatement, as well as flight and maintenance requirements. CAR also corresponds to the broad areas of aviation which Transport Canada, Civil Aviation is mandated to regulate (e.g. personnel licensing, airworthiness, commercial air services, etc.). CAR is specific to concerns to residents at YBW CAR Minimum altitudes and Distances Under the CAR, this regulation applies to all types of aircraft jets, propellers, helicopters and hot air balloons. Over builtup areas, aircraft must stay at least 1000 ft above any obstacles that are within a 2000 foot radius of the aircraft. Hot air Springbank Airport Noise Study 2009 Page 7

14 balloons must be at least 500 feet above the ground. However, this does not apply to aircraft conducting a take off, approach, or landing, or those having special permission (such as air photo flights, pipeline patrol flights and flights involving police, fire, ambulance and other provincial or federal agencies). Air Traffic Control may require an aircraft within the Calgary Control Zone to fly at an altitude different than the regulation minimum. Aircraft must stay at least 500 feet above any obstacle and within a 500 foot radius of the aircraft, with the exception of built up areas. Aircraft may fly, such as STARS Air Ambulance and HAWCS, at less than 500 feet above the ground, if performing a special task, as an exemption under the CARs. 2.4 Policies Engine Run up Policy Aircraft engine run ups are performed as a part of a standard maintenance schedule. A run up usually involves the running of an aircraft s engines at flight specifications for a period of time to simulate flight. The Authority has an Aircraft Engine Run up Policy that outlines the requirements for operators conducting aircraft engine run ups at YBW. Engine runups are routine aircraft engine maintenance tests performed as a check to ensure safe and reliable operation of the aircraft engine, as required by Transport Canada and aircraft engine manufacturers. In an effort to reduce noise impacts, formal procedures for ground run ups have been established. The underlying principle is that run ups will be positioned to address safety issues and to minimize noise impacts on surrounding communities. 2.5 Other Standards Noise emitted from aircraft during flight is not illegal, nor does it violate any community noise standards. Aeronautics is a federal jurisdiction and aircraft that are certified to operate in Canada already meet noise certification standards. However, because there are no measurable noise standards for aviation to evaluate itself against, a comparison to Alberta s Energy Utility s Board s Directive 038: Noise Control (EUB, 2007). Directive 038: Noise Control states the requirements for noise control as they apply to all operations and facilities under the jurisdiction of the Alberta Energy and Utilities Board (EUB). The requirements solely address environmental noise from oil and gas facilities. Table 1 provides the levels required to meet night time and daytime noise levels at sites in rural environments as prescribed by the EUB. Table 1 Basic sound levels for night time ( hrs) and daytime ( hrs)* (EUB 2007) Dwelling per unit of density Proximity to Transport 1 8 Dwellings (LAeq) Dwellings (LAeq) >160 Dwellings (LAeq) Category Category Category *Notes: Category 1 dwelling units more than 500 m from heavily travelled roads and/or rail lines and not subject to frequent aircraft flyovers. Category 2 dwelling units more than 30 m but less than 500 m from heavily travelled roads and/or rail lines and not subject to frequent aircraft flyovers. Category 3 dwelling units less than 30 m from heavily travelled roads and/or rail lines and/or subject to frequent aircraft flyovers. Density per quarter section refers to a quarter section with the affected dwelling at the centre (a 451 m radius). For quarter sections with various land uses or with mixed densities, the density chosen is then averaged for the area under consideration. Springbank Airport Noise Study 2009 Page 8

15 The daytime adjustment recognizes that daytime ambient sound levels are commonly 10 LAeq higher than nighttime levels and that nighttime noise disturbances are generally considered less acceptable. Airport operations do occur 24 hours a day, 7 days a week, however, night time operations are significantly decreased as NAV CANADA s air traffic control tower is closed between hours. During the duration of the study s night time hours (August 17 27; hours), there was a total of 17 operations that occurred. Table 1 is to be utilized simply to evaluate sound levels in communities surrounding YBW. They do not apply to aircraft operations, but they do provide insight into what regulatory bodies perceive as acceptable noise levels in rural and semirural environments. Springbank Airport Noise Study 2009 Page 9

16 3.0 NOISE COMMUNITY CONCEPTS AND TERMINOLOGY Noise is a very complex physical attribute. The properties, measurement, and presentation of noise involve specialized terminology that is often difficult to understand. To provide a basic reference on these technical issues, this chapter provides an introduction to the fundamentals of acoustics and noise terminology, the effects of noise on human activity, and community annoyance. Appendix A also provides a simple acoustic glossary for review. 3.1 What is Sound? Sound is a complex vibration transmitted through the air or other medium which, upon reaching our ears, may be perceived as desirable or unwanted. When the sound is unwanted it is normally referred to as noise Sound Propagation Sound requires a medium in which to propagate, in the case of YBW this medium is air. Sound moves outwards from its point of origin in the form of longitudinal or compression waves. Sound waves produced by aircraft are spherical, i.e. equal amounts of sound or acoustic energy travels in all directions. For road traffic, the sound waves are hemispherical due to the constraint imposed by the ground surface. As the distance is increased between the source (e.g. aircraft) and the receiver (person), the sound level experienced attenuates or is reduced. The sound level is reduced by approximately 6 db for every doubling of distance for aircraft and 3 db for heavy road traffic. For example, 60 db measured at 100 metres would reduce to approximately 54 db and 48 db at 200 and 400 metres respectively for an aircraft. 3.2 Noise Metrics Terminology In many cases standards and regulations specify which parameters must be measured as well as how to set up measurement equipment and handle various factors such as meteorological conditions (e.g., wind, cloud cover, humidity). Thus, understanding noise and results of noise assessments are never a simple figure, such as 77 decibels (dba). It is the value of specific parameters or indicators obtained under known and documented conditions. The following is a description of some of the more common noise terminology. This section provides background on the parameters measured and discussed in this document Decibels (db) The human ear is capable of sensing an enormous range of sound intensities. In a fashion analogous to the familiar Richter scale of earthquake magnitude, a logarithmic scale of sound levels has been developed to compress the large range of human hearing sensations. The basic unit of sound is the decibel (db) and the normal extent of the human ear aural experience (from threshold of hearing to threshold of pain) falls within the range from 0 to 130 db. Decibels are sound pressure measurements. Sound pressure level is a measure of the sound pressure of a given noise source relative to a standard reference value. As mentioned above, db are logarithmic quantities, relating the sound pressure level of a noise source to the reference pressure level. The reference pressure value is typical of the quietest sound that a young person with good hearing is able to detect. Springbank Airport Noise Study 2009 Page 10

17 Several filters have been developed that match the sensitivity of our ear and thus help us to judge the relative loudness of various sounds made up of many different frequencies. The so called A filter is the best measure for most environmental noise sources. Sound pressure levels measured through this filter are referred to as A weighted levels, and are measured in A weighted decibels or (dba). For this monitoring program A weighted decibels will be used for analysis Loudness and the Decibel Scale The nature of db scales is such that the individual sound level for different noise sources cannot be added directly to give the combined sound level of these sources. Two equal noise sources radiate twice the sound energy as one noise source. The human ear does not perceive the resulting noise as being twice as loud, but only recognizes it as being noticeably louder. This is the ear s way of managing the large range of sound intensities that is exposed to. The decibel scale functions in a similar way. For example, two small propeller aircraft each producing 70 dba at a given distance is observed flying together at equal distances from the observer, they would produce approximately 73 dba, not 140 dba. When two noise sources differ by 10 db, the composite noise level will be only 0.4 db greater than the louder source alone. A 3 dba increase in noise level, as is achieved by the doubling of equal noise sources, is typically judged by individuals to represent only about a 20% increase in loudness. Similarly, each 6 dba increase in noise level produces approximately 40% increase in perceived loudness while a 10dBA increase corresponds to a doubling (or 100% increase) of loudness. Thus, an aircraft that produces a noise level of 80 dba at the ground would typically be judged to be twice as loud as one that produces 70 dba, but only half as loud as aircraft that produces 90 dba. Most people have difficulty distinguishing the louder of two noise sources if they differ by less than db. Research into the human perception of changes in sound level indicates the following. A 3 db change is just perceptible. A 5 db change is clearly perceptible. A 10 db change is perceived as being twice or half as loud. For example, see below. = 60 dba + = 63 dba = 70 dba A 10 dba change is equivalent to a perceived doubling or half as loud. Springbank Airport Noise Study 2009 Page 11

18 3.2.3 Equivalent Sound Level (LAeq) Community noise from road, rail, aircraft and other local sources are rarely steady. It varies in intensity from second to second, minute to minute or hour to hour. When attempting to describe the overall noise exposure of a community over a period of time, it is necessary to average the noise level in some way. An average noise level descriptor is the Equivalent Sound Level (Leq). The LAeq, is a measure of the exposure resulting from the accumulation of A weighted decibel sound levels over a particular time period (e.g., 1 hour, 8 hour, 24 hour). Conceptually, LAeq may be thought of as a constant sound level over the period of interest that contains as much sound energy as the actual time varying sound level with its normal peaks and valleys. It is important to realize, however, that the two signals (the constant one and the time varying one) would sound very different from each other if compared in real life. Variations in the average sound level suggested by LAeq are not an arithmetic value, but a logarithmic ( energy averaged ) sound level. Thus, loud events dominate any noise environment described by the metric LAmax and LAmin The maximum instantaneous noise level, or LAmax, created during an aircraft noise event is an indicator of the potential impact on the community since it relates directly, though not uniquely, to the ability of the noise event to interfere with essential human activities, such as speech communication and sleep. The LAmax is the point at which the sound associated with an event reaches its instantaneous maximum intensity in a given period of time. LAmax represents the maximum noise level heard (usually in units of dba) during a single aircraft event (such as a flyover during an arrival or departure). While the duration of an aircraft noise event near an airport is generally within the 15 to 50 second range, the instantaneous noise level is at or near the LAmax for only a few seconds. The LAmin represents the minimum instantaneous noise level recorded in a given period of time during noise monitoring Exceedance Level (L AN ) Human response depends directly upon the range with which noise levels vary in a given environment. For a given LAeq, one would find a higher, more steady level tolerable than a lower background level with frequent noise intrusions. Exceedance levels are those noise levels that exceed for a given percentage N of the monitoring time. LA90 is the noise level that was exceeded for 90% of the time whereas LA5 is the noise level that was exceeded 5% of the time. LA90 is used to estimate the residual background sound environment. For this study a LA90 and LA5 measurement will be measured. 3.3 Measuring Community Noise Noise in the community is measured with a Sound Level Meter. These meters have three basic components. 1. Microphone which senses the minute fluctuations in atmospheric pressure caused by sound waves. 2. Amplifier and filter sections which boost the tiny electrical signal produced by the microphone and apply the appropriate frequency weighting most often A weighted. 3. Display section which allows the noise level to be continuously read out with a digital display. The speed at which the display can respond to variations in noise level is selectable. Today, many sound level meters have substantial built in memory and other digital processing and data storage, which allow the equipment to operate unmanned, perform statistical analyses of the sound environment and store the Springbank Airport Noise Study 2009 Page 12

19 information over extended monitoring periods. Sound level meters sample the instantaneous noise environments in the community many times per second and store the information according to pre selected parameters. The preselected parameters depend on the type of sound being measured and the purpose of the measurements. 3.4 Factors that Influence Noise Propagation Wind and relative humidity are one of many factors that influence noise and its propagation. Wind carries sound waves, and a decrease in relative humidity increases sound propagation. Topographic features and structural barriers that absorb, reflect, or scatter sound waves can result in increased or decreased noise levels. Atmospheric conditions (wind speed and direction, humidity levels, and temperatures) can also affect the degree to which sound is attenuated over distance. Echoes off topographical features or buildings can sometimes result in higher sound levels (lower sound attenuation rates) than normally expected. Temperature inversion and attitudinal changes in wind conditions can at times refract sound waves to a location at a considerable distance from the noise source. Variances in winds and relative humidity are very local in nature and were not monitored for this study. 3.5 Typical Range of Noise Exposures in the Community In normal everyday experience, we are exposed to sounds ranging from 30 dba (rustling of leaves or a clock ticking) to dba (lawn mowers or heavy truck). Figure 5 shows a variety of common sources of noise in an urban environment, including several aircraft 2 and indicates the A weighted noise levels that they typically produce. Figure 5 Typical sound levels in A weighted decibels (dba) (City of Vancouver 2005). 2 Decibel data taken from the Federal Aviation Authority document AC 36 3H Estimated airplane noise levels in A weighted decibels. Springbank Airport Noise Study 2009 Page 13

20 3.6 Aircraft Noise Impacts and Impact Thresholds Types of Community Noise Impact caused by Aircraft Noise Like any type of noise, aircraft noise has the potential to create impacts within residential areas in two basic ways: through interference with essential activities, primarily communications, relaxation and sleep; and through the creation of annoyance leading to a negative reaction by individuals or the community. While displaying a certain amount of interpersonal variation, thresholds for the onset of sleep and speech interference, due to intrusive noise have been established can be related to the instantaneous noise levels. Thresholds for the onset of annoyance are more difficult to define as personal factors and the character of the noise play a large role. Annoyance is linked to speech and sleep interference, whereas the degrees of annoyance and negative reaction among members of a community have been found to correlate with measures of overall noise exposure Annoyance The primary potential effect of aircraft noise on exposed communities is one of annoyance. Noise annoyance is defined by the U.S. Environmental Protection Agency as any negative subjective reaction on the part of an individual or group (US EPA, 1974). Social survey data have long made it clear that individual reactions to noise vary widely for a given noise level. Nevertheless, as a group, peoples aggregate response to factors such as speech and sleep interference and desire for an acceptable environment is predictable and relates well to measures of cumulative noise exposure Speech Interference A primary effect of aircraft noise is its tendency to drown out or "mask" speech, making it difficult to carry on a normal conversation. As an aircraft approaches and its sound level increases, speech becomes harder to hear. As the ambient level increases, the talker must raise his/her voice, or the individuals must get closer together to continue talking. For typical communication distances 1 to 1.5 meters, acceptable outdoor conversations can be carried on in a normal voice as long as the ambient noise outdoors is less than about 65 dba (FICON, 1992). If the noise exceeds this level, intelligibility would be lost unless vocal effort was increased or communication distance was decreased. Springbank Airport Noise Study 2009 Page 14

21 4.0 BUILDING CODES AND SOUND REDUCTION Because this monitoring study monitored outdoor sound levels, there needs to be some basic assumptions on noise reduction using standard building practices. Transportation noise from road traffic, trains and aircraft is low frequency noise. The Outdoor indoor Transmission Class (OITC) (referenced in ASTM E 1332, 1998; Standard Classification for Determination of Outdoor/Indoor Transmission Class) is a single number rating of the attenuation of floor, wall and ceiling that indicates the ability to attenuate transportation noise. OITC utilizes a source noise spectrum that considers frequencies down to 80 Hz (Aircraft/Rail/Traffic) and is weighted more to lower frequencies. Humans hearing range is typically between 500 and 8000 Hz. The use OITC at the lower level of 80 Hz allows for the management of low frequency noise, which often is not heard but is felt through vibrations. 4.1 Walls A simple wood stud wall with lightweight surface, gypsum board and oriented strand board (OSB), would have an OITC of about 25 decibels (dba) while the same wall with brick added to the exterior would have an OITC of about 40 db sound insulation values ranging from mediocre to superior. 4.2 Windows Typical windows with double glazing (two layers of three millimeter glass with a 13 mm air space) have an OITC rating of about 22 db. The greatest improvement in the sound insulation of windows can be achieved by using thicker glass and a larger air space. Laminated glass and special gases in the cavity can provide small improvements at higher frequencies. Standard double glazed windows can be improved inexpensively by installing a conventional storm window with a large air space between the storm and the regular window. The addition of a storm window with 76 mm airspace to a double glazed aluminum casement window can increase the OITC rating from 23 to 30 db, a substantial and clearly noticeable improvement. 4.3 Roof Because the roof is often the largest area exposed to aircraft noise, it is important to ensure that a particular construction is capable of providing an effective sound barrier. A sloping roof construction with asphalt shingles on the exterior, two layers of 13 mm gypsum board mounted on resilient channels for the interior surface, with roof vents and R40 thermal insulation provides an OITC of 43 db. Flat roofs with similar details but based on 356 mm wood trusses or 235 mm wood joists provide only slightly less sound insulation. However, replacing the asphalt shingles on OSB sheathing with steel sheeting directly attached to the wood trusses reduces the OITC rating by four db, a small but noticeable degradation. Springbank Airport Noise Study 2009 Page 15

22 5.0 NOISE MONITORING METHODOLOGY In the previous three studies, six different residential locations were used. For this study, two of the previous six monitoring locations have been discontinued. In response to the loss of two sites, one new site was added to the 2009 monitoring study. This additional site was requested by (SACNCC). Four sites are still being used to ensure consistency in the analysis of community noise levels between the three studies. This study was initiated in consultation with local Springbank residents, and The Authority, and as stated previously, is a followup to the 1998 and 1999 work. In June 2009, YBW hosted its annual SACNCC meeting where it was requested that a follow up to the previous monitoring work be conducted. At this time five stakeholders, four original stakeholders and one new, were contacted to discuss and commence the 2009 monitoring program. Portable noise monitoring is very important as it provides context to the local soundscape of an area especially as well as providing community outreach. Because the information collected will be released to the public, it is essential that data released is accurate, and its integrity is not compromised. The process detailed below provides the continued methodology for consistency which will help ensure that the data collection process is accurate and the integrity of the data cannot be questioned. 5.1 Ambient Noise Monitoring Equipment and Procedures This study focused on the single event noise metrics (LAeq, LAmax and LAmin) for comparison to previous monitoring that was conducted at YBW. The noise monitor recorded ambient noise levels at each site and did not discriminate between the different noise sources. Therefore, the average noise levels (hourly LAeq) recorded are a measure of all noise/sound at a particular location including, vehicles and aircraft, and ant other background noise that made be a part of the community soundscape, and thus does not discriminate. The study aimed to conduct the monitoring on days when disruptive activities did not take place, such as lawn mowing and farming activities General Approach to Ambient Noise Monitoring The Authority conducted a total of 120 hours of unmanned noise monitoring at five residences within the vicinity of YBW. All monitoring took place during between August 17 and August 27, Each of the five locations had total of 24 hours of continuous sound monitoring recorded. Monitoring was conducted on a weekday and those days with amicable weather. Amicable weather is defined as conditions with no precipitation, warm temperatures, and wind activity less than 5 m/s, and/or wind gusts exceeding 10 m/s. Wind speed higher than 5 m/s, temperatures below 10 C, or above 50 C, and precipitation events will affect the validity of sound level measurements. A Larson & Davis Hand held Analyzer 831 (SLM) was used to capture the sound environment, which continually recorded and stored LAeq sound data. The SLM consists of a microphone with windscreen positioned on a tripod that is connected to the sound level meter itself situated on the ground in a waterproof protective case (Figure 6). The analyzer was set up to record sound data for every second over a 24 hour period of time at each individual location. The sound data from each location was downloaded into a PC prior to set up at the next location. The units were operated on a 24 hour clock with brief breaks for location changes, battery changes, calibrations, and other basic maintenance Springbank Airport Noise Study 2009 Page 16

23 requirements. Two Authority team members conducted the set up and maintenance of the monitoring. Staff went to the after each 24 hour session of monitoring to download data and move the SLM to a new location. Figure 6 Larson & Davis Hand held Analyzer 2250 (SLM) Instrumentation Set up and Calibration The SLM was set up in the open outdoors in the backyard of each of the five residences. The SLM was positioned within the confines of the residences property, but well away from any large sound reflecting surfaces such as walls, trees and other significant sources of community noise. The microphone was fitted with a windscreen and set on top a tripod approximately 1.5 metres off the ground. The battery and SLM was stored in a locked case adjacent to the microphone. At the start of each 24 hour measurement period, the calibration of the SLM was checked using the Larson & Davis Calibrator Five calibrations were conducted over the course of the monitoring and were completed at the onset of each daily recording session. The SLM maintained a log of all calibration checks which can be later used to assess the significance of any drift in sensitivity over the duration of the monitoring period. All calibrations conducted over the course of the noise monitoring study show that calibration drift was generally within 0.05 to 0.6 dba. No adjustments for instrument drift during the measurement period were warranted during the survey. Calibration records for each calibration conducted for this study are provided in Appendix B. 5.2 Existing Ambient Noise Sources When conducting noise monitoring work it is important to recognize that locations will already have an existing noise foot print that is unique to that location. All three locations are located in a semi rural environment and are within at most one kilometre of another dwelling. The most isolated (proximity to other homes) locations would be the Location 1and Location 4 with the other remaining Locations located within acreage communities. 3 SLM used at YBW. Picture taken at Calgary International Airport August 16, Springbank Airport Noise Study 2009 Page 17

24 Other sources of existing noise observed to the area, included bird song, wind rustling the leaves on trees, lawn mowers, and vehicle traffic. Location 1 and Location 4 both experience Trans Canada Highway noise as well as noise from Township 250 road traffic. 5.3 Ambient Noise Monitoring Locations The monitoring locations were selected based on previous monitoring done within the community. By choosing the same locations provides an understanding as to how the soundscape has changed over the years. Unfortunately, two of the six sites were lost due to extenuating circumstances and in response to that an additional site was added. The additional locations, Location 2 and Location 3 were chosen based on individual interest and concerns from those individuals regarding YBW s operations and noise emanating. Figure 7 shows the location of monitoring for Selection criteria included the following major factors. All sites were on properties were under or adjacent to a flight path at YBW. The focus of the measurements was in areas exposed to the highest noise levels, including areas where aircraft typically travelled in the closest proximity to and locations where aircraft travelled overhead. Equipment security is a practical matter. Once a measurement site was identified, specific monitor locations were selected to isolate the monitors from non aircraft levels and to allow the monitor to be secured. Table 2 lists the measurement locations, the dates and times of measurements, and the number of hours of monitoring. A total of 120 hours (24 hours at each location) of measurements were conducted at the five locations. Figure 6 provides a schematic of monitoring locations in reference to YBW. For the locations that had been previously monitored, it was the intention to place the SLM in close proximity to the previous monitoring spot. Table 2 Summary of Noise Measurement Locations Location # Start End Date Time Date Time 1 August 17 10:09 August 18 10:30 2 August 18 11:08 August 19 11:10 3 August 24 10:57 August 25 11:27 4 August 25 12:03 August 26 12:12 5 August 26 12:46 August 27 14: Location 1 Location is located approximately 1.5 kilometres west off the end of Runway 25 along Range Road 35. Location 1 has had concerns with aircraft noise over her home for some time, and agreed to have her location monitored. Location 1 residence is surrounded by trees thus it was necessary to ensure that the SLM was positioned well away from trees and the dwelling itself. The SLM was set up in the field just to the north of the residence which is adjacent to the flight path for Runway 07/25. Location 1 experiences activity from departures off of Runway 25, arrivals to Runway 07 and circuit training from flight school activity. Springbank Airport Noise Study 2009 Page 18

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26 5.3.2 Location 2 Location 2 is located approximately 4 kilometres north east of YBW at Rocky Range View, west of Range Road 33. The residence is located on flat ground with no surrounding treed vegetation. This allowed for easy placement of the SLM. The SLM was placed in the front yard of the residence approximately 20 metres from the dwelling. Location 2 residence experiences activity from north departures off of Runway 34, arrivals to Runway 16 and circuit training from flight school activity Location 3 Location 3 residence is located just north of YBW in the acreage community of Country Lane Estates. Location 3 residence is approximately 5 kilometres northeast of YBW along Range Road 33. The SLM was set up approximately 15 metres southwest of the residence in an open field. Vegetation cover was not a concern at this location. Location 3 residence experiences activity from north departures off of Runway 34, arrivals to Runway 16 and circuit training from flight school activity Location 4 Location 4 is located approximately 3.5 kilometres east of YBW, just off of Township Road 250. The SLM was set up approximately 100 metres east of the residence, in an open field. It was a recommendation from the residents due to maintenance activity that would be occurring in the yard. As well, high and dense vegetation cover around the dwelling was an issue, thus the open field did provide a better option for monitoring. Location 4 sees activity from departures off of Runway 07, arrivals to Runway 25, as well as circuit training from flight school activity Location 5 Location 5 is situated directly east of the airport approximately 4.5 kilometres from YBW within the community of Calling Horse / Crocus Ridge. The SLM was set up approximately 40 metres west of the Hick s residence in the backyard. Vegetation cover was not a concern at this location. Location 5 sees activity from departures off of Runway 07, arrivals to Runway 25 as well as circuit training from flight school activity. 5.4 General Flight Path of Aircraft over YBW Section explains the type of aircraft movements at YBW. However, the predominant aircraft movements are a result of aircraft training activities. These training activities can be broken down into two types: rotary and fixed wing. Training circuit patterns will be explained below, which provides context to how aircraft Springbank Airport Noise Study 2009 Page 20

27 6.0 MONITORING RESULTS 6.1 Monitoring Metrics During the monitoring study, just over 120 hours of continuous sound data was collected. The data gathered for this study is more voluminous than previous studies in 1999 and The data gathered includes: LAeq; LAeq (1 hour) LAeq (24 hour) LAeq (8 hour) Night time: 2300 and 0700 hours; LAeq (16 hour) Day time: 0700 and 2300 hours; LAmax (instantaneous value) ; LAmin (instantaneous value); LA5; and LA90. The LAeq hourly values are consistent with the previous noise monitoring that has occurred out at Springbank Airport and are comparable to the 1999 and 1998 monitoring work. The other metrics are newer and these values will not be comparable to the previous studies, but they do provide insight to the sound scape at YBW as well as provide a baseline for future comparison if further noise monitoring is required Noise Level from Monitoring Locations From August 16 27, 2009 the SLM sampled the noise environment and generated noise level histories and statistics. This data includes all other noise sources in the community, as well as noise emitted from aircraft. The noise histories are useful when illustrating the variation of average noise levels throughout the day and night, as well as indicating the range of noise levels experienced at various times of the day. Figures 8 through 12 provide the 24 hour time histories, in 60 minute intervals of the LAeq, the LAmax and the LAmin. These figures provide context to the sound scape for each hour at each monitoring location. Figure 8 Location 1 Figure 9 Location 2 Figure 10 Location 3 Figure 11 Location 4 Figure 12 Location 5 Springbank Airport Noise Study 2009 Page 21

28 Figure 8 Hourly LAeq, Lmax and Lmin Values over a 24 hour period: Location 1. Figure 9 Hourly LAeq, Lmax and Lmin Values over a 24 hour period: Location 2. Springbank Airport Noise Study 2009 Page 22

29 Figure 10 Hourly LAeq, Lmax and Lmin Values over a 24 hour period: Location 3. Figure 11 Hourly LAeq, Lmax and Lmin Values over a 24 hour period: Location 4. Springbank Airport Noise Study 2009 Page 23

30 Figure 12 Hourly LAeq, Lmax and Lmin Values over a 24 hour period: Location Exceedance Noise Levels Most environmental noise is a conglomeration of distant noise sources which results in a relatively steady background noise having no identifiable source. These distant sources may include traffic, wind in trees, industrial activities, etc. and are relatively constant from moment to moment. Superimposed on this slowly varying background, is a succession of identifiable noisy events of brief duration. These may include nearby activities such as single vehicle pass bys, aircraft flyovers, etc. which cause the environmental noise level to vary from instant to instant. Environmental noise varies over time, and may be reported in terms of noise level that is exceeded for a certain percentage (N%) of total measurement time LN. As discussed earlier, LA90 level is the noise level that was exceeded for 90% of the of the total measurement period. The LA90 value provides a picture of background noise levels and gives an indication of the relative noticeability of all types of noise events at the site. The LA5 is the noise level that was exceeded for 5% of the of the total measurement period. LA5 does not represent the maximum sound at a location, but it does represent the upper limits of the sound scape. The sound scape recorded for this monitoring study consists of all environmental sources of noise, which includes aircraft, but also such noises as lawn mowers and vehicles. The SLM does not discriminate between aircraft noise and all other noise sources. Figure 13 provides the average noise levels at the monitoring locations near YBW as represented by the arithmetically averaged hourly LA90 and LA5 levels over 24 hours. Springbank Airport Noise Study 2009 Page 24

31 Figure 13 Noise exceedance levels at each monitoring location at YBW Location 1 had the highest LA5 4 value with 5% of all sound recorded averaging greater than 57.2 dba. However, the Location 4 location had the highest LA90 5 value with 90% of all sound recorded averaging greater than 35.9 dba. To understand what 57.2 dba and 35.9 dba means in a noise level refer back to Figure 1. This figure provides a schematic of noise levels emitted from common noise sources in the environment. The noise recorded at each individual site and the metrics provided do show that each site does represent a rural location for 90% of the time with the exception of the Location 4 and Location 5. Location 4 and Location 5 are twice as loud as the Location 2 and Location 3, but this could be due to the Location 4 s proximity to TWP 250 and Location 5 s residence being in a higher density community where quintessential community noises will dominate the soundscape. As each monitoring location gets closer to the Trans Canada Highway, the larger the LA90 and LA5 exceedance values become. The Trans Canada Highway will have an effect on noise levels in the area although this type of noise is less noticeable than aircraft noise, but not necessarily quieter. 4 5% of 24 hours is 72 minutes. 5 90% of 24 hours is 1260 minutes, or 21 hours. Springbank Airport Noise Study 2009 Page 25