# Part IV - Aircraft Noise

## 4.1 General

An assessment of the annoyance resulting from exposure to aircraft noise is often essential to both aviation planners and those responsible for directing the nature of development of lands adjacent to aerodromes. This section will discuss noise measurement, annoyance prediction, the Noise Exposure Forecast and the Noise Exposure Projection. It also contains an assessment of various land uses in terms of their compatibility with aircraft noise.

### 4.1.1 Noise Measurement

The sound pressure level created by an aircraft (or any other noise source) can be measured by means of a sound level meter. The microphone of the sound level meter senses the pressure fluctuations over a short period of time. The sound pressure is the root mean square value of the difference between atmospheric pressure and the instantaneous pressure of the sound, the mean being read over several periodic cycles. For mathematical convenience, the logarithmic parameter called sound pressure level (SPL) is used. The unit of sound (noise) measurement is the decibel (dB).

A particular sound signal may comprise several different frequencies to which the human ear may respond in various ways. In order that noise measurements may relate more closely to loudness as judged by the average person, sound level meters are equipped with weighting networks which make use of information related to the frequency response characteristics of the human ear. Some sound level meters have the capability of reading on A, B, C, and D weighting scales, and decibel values are correspondingly indicated as dB(A), dB(B), dB(C) or dB(D), according to the weighting network used. However, the dB(A) is the most common.

The noise metric known as Perceived Noise Level (PNL), measured in the unit PNdB, provides a frequency weighting system which attempts to more closely approximate the subjective reaction of the human ear to an aircraft noise stimulus. Although weighting networks are available which provide a means of directly measuring approximate PNL values, i.e., dB(D), true PNL values are determined by the analysis and treatment of sound pressure levels in various 1/3 octave bands.

A more sophisticated noise metric, the Effective Perceived Noise Level (EPNL), expressed in the unit EPNdB, was developed specifically for use in the measurement of aircraft noise. The EPNdB is the metric that forms the basis of noise certification of aircraft. This metric is basically similar to the PNL except that corrections have been applied to account for the effects of discrete tones and the duration of the noise event, i.e., factors which contribute to the annoyance of the listener.

### 4.1.2 Predicting Annoyance

In addition to the annoying characteristics of an individual noise signal, overall subjective reaction to noise is dependent on the number of times the disturbance occurs as well as the daily distribution of these events. These factors must be included in any noise forecasting system if it is to be applicable to the communities located in the vicinity of aerodromes. The Noise Exposure Forecast (NEF) system made available by Transport Canada takes into consideration all of these factors.

The NEF system provides for the summation of noise from all aircraft types operating at an aerodrome based on actual or forecast aircraft movements by runways and the time of day or night the events occur. The large number of mathematical calculations necessary for the construction of NEF contours requires the use of computer techniques for the practical application of this system.

### 4.1.3 The Noise Exposure Forecast System (NEF)

The Effective Perceived Noise Level is the basis for estimating noise annoyance in the Noise Exposure Forecast system.

The data required for determining NEF contours consist of EPNL versus distance information for various aircraft types, along with generalized aircraft performance data. In calculating NEF at a specific location, the EPNL contribution from each aircraft operating from each runway is assessed by considering the distance from the point in question to the aircraft, and then obtaining EPNL values from the appropriate EPNL versus distance curve. The noise contributions from all aircraft types operating on all runways are summed on an anti-logarithmic basis to obtain the total noise exposure at that one location. Thus, the determination of NEF contours is strictly a numerical calculation procedure. As stated previously, due to the large number of mathematical calculations involved, computer techniques provide the only practical means of constructing NEF contours.Footnote 1

## 4.2 Production of Noise Contours - Aerodromes That Are Neither Owned Nor Operated and Managed by Transport Canada

The preparation and approval of noise contours for aerodromes that are neither owned, nor operated and managed by the Federal Government is not a responsibility of Transport Canada. Transport Canada will conduct a technical review of an NEF, NEP or Planning Contour if requested by the sponsoring aerodrome operator or airport authority provided that:

• (a) the Aerodrome owner or operator initiates this action;
• (b) the Aerodrome owner or operator supplies or approves a projection of aircraft traffic, both as to type and numbers; and
• (c) the Aerodrome owner or operator uses the noise impact prediction methods, procedures and recommended practices relating to aircraft operations as established by Transport Canada.

## 4.3 Noise Exposure Contours

There are three types of noise exposure contours produced depending on the time element involved. These are Noise Exposure Forecasts (NEFs), Noise Exposure Projections (NEPs) and Planning Contours. Transport Canada may provide, upon request from a sponsoring aerodrome operator or airport authority, a technical review of any contours calculated to determine if the NEF computer model has performed accurately and has been applied correctly.

### 4.3.1 Noise Exposure Forecast (NEF)

The Noise Exposure Forecast (NEF) is produced to encourage compatible land use planning in the vicinity of aerodromes. Traffic volume and aircraft type and mix used in calculating the noise contours are normally forecast for a period of between five and ten years into the future (See NOTE). Runway geometry should be the current layout plus any changes forecast to be completed prior to the end of the forecast period. Noise contours (NEFs, NEPs and Planning Contours) are the property of the sponsoring aerodrome operator or airport authority which may be make them available to provincial and local governments. The use of the contours will enable planners to define compatible land use in the vicinity of aerodromes.

Note:Transport Canada does not retain copies of NEFs and NEPs submitted to it for technical review. Upon completion of the review, all materials submitted are returned to the sponsoring aerodrome operator or airport authority. These materials are the property of the sponsoring aerodrome operator or airport authority.

Transport Canada does not support or advocate incompatible land use (especially residential housing) in areas affected by aircraft noise. These areas may begin as low as NEF 25. At NEF 30, speech interference and annoyance caused by aircraft noise are, on average, established and growing. By NEF 35 these effects are very significant. New residential development is therefore not compatible with NEF 30 and above, and recommends that it not be undertaken.

### 4.3.2 Noise Exposure Projection (NEP)

It is recognized that much land use planning involves projections beyond five years into the future, when aircraft fleet mixes and runway configurations are most likely to be different from the known conditions of today. To provide provincial and municipal authorities with long range guidance in land use planning, Transport Canada introduced the Noise Exposure Projection (NEP). The NEP is based on a projection (not a forecast) of aircraft movements for more than 10 years into the future, and includes aircraft types and runway configurations that may materialize within this period. NEPs may be made available in the same manner as NEFs.

### 4.3.3 Planning Contour

The third type of noise contour is the Planning Contour which is produced to investigate planning alternatives and should be labelled as such. In the same manner as NEFs and NEPs, these contours are the property of the sponsoring aerodrome operator or airport authority.

## 4.4 Production of Noise Contours: DND Aerodromes

Production of noise contours for aerodromes used solely by the Department of National Defence (DND) is the responsibility of DND as to data input and production. Production of Noise contours for DND owned joint use aerodromes with a civilian airport authority is the responsibility of DND as to data input and production. When requested, these contours will be published subject to Commander, Canadian Air Division (1CAD)'s approval of the accuracy of the contours.

## 4.5 Noise Contour Maps

It may be necessary for computer-produced contour lines to be mechanically smoothed to remove irregularities that arise in the plotting process. This should be done particularly in areas of sharp corners or tips. The convention used for depicting the NEF and NEP 40, 35 and 30 contours on maps is a solid line. The printing and any subsequent distribution of contour maps is not the responsibility of Transport Canada. These functions may be undertaken by the sponsoring aerodrome operator or airport authority as they are the property of the aerodrome.

## 4.6 Community Response to Noise

During developmental work on preliminary noise rating systems, it was established that community response to aircraft noise correlated well with the noise contours then in use. Case histories of noise complaints at twenty-one aerodromes were analyzed as to severity, frequency of complaint, and distribution around the aerodromes to establish a relationship with known noise values. The results of this work, which may be found in Table 1 (see below) have been used for relating land use recommendations to NEF contour levels.

The analysis of the effect of aircraft noise on various working and living environments is a complex matter. For each case where there is a note in the Land Use Tables (Table 2) (see below) it is desirable that a noise climate analysis or a noise reduction requirement analysis be undertaken, since each note indicates a particular specialized problem. Many of the factors that would be considered in such analyses are subject to changing technology. Also, the attitudes of those exposed to the noise environment are subjective and varied. Since these factors evolve, authorities undertaking analyses of noise climates and noise reduction requirements in buildings should consult using most recent information with agencies conducting these reviews. The National Research Council has undertaken work in this area and validated the results of the NEF System and interpretation of noise exposure areas in 1996.

### 4.6.1 New Aerodromes and Community Response to Noise

For the purposes of this section, "New Aerodrome" means any land designated by the Governor in Council as an "Airport Site" under the Aeronautics Act after January 1, 2001.

Where an aerodrome is already surrounded by residential or other noise sensitive land uses, the intent of land use planning guidelines is to prevent any increases in incompatible land use. As urbanization increases, any new aerodrome would, by necessity, be planned for and built in non-urban areas. Therefore, where a new aerodrome is planned on land designated as an airport site, an opportunity exists to establish appropriate land use planning guidelines that recognize the unique noise environment of a non-urban area and preserve the balance between the integrity of the future aerodrome and the quality of life of the community that it will serve.

The encroachment of incompatible, sensitive land uses is clearly a vital factor in planning and establishing appropriate protection criteria for new aerodromes. The best and often only opportunity to establish a sufficient buffer zone to control noise sensitive development around a new aerodrome is in the initial planning stage of that new aerodrome. This opportunity diminishes quickly as the aerodrome develops and community land use patterns become established.

In addition to the traditional approach of defining land use planning guidelines, pertinent factors considered in a study of land use guidelines for new aerodromes included not only individual activity interference (speech and sleep) criteria, but also habituation to noise, the type of environment (non-urban versus urban environment), community attitudes toward the noise source, the extent of prior exposure to the noise source, and the type of flight operations causing the noise.

For new aerodromes, Transport Canada recommends that no new noise sensitive land uses be permitted above 25 NEF/NEP. Noise sensitive land uses include residential, schools, day care centres, nursing homes and hospitals. This approach is the single most practical for reasons of ease of implementation and administration since below this threshold, all noise-sensitive land uses would be permitted without restrictions or limitations. The guidelines for all other land uses remain unchanged from Table 2. This buffer would also offer protection against the long term uncertainties inherent in planning for a new aerodrome.

To implement this NEF 25 criterion, NEF and NEP maps for new aerodromes must depict the 25 contour as a solid line in addition to the noise contour requirements set out in Section 4.5.

## 4.7 Recommended Noise Control Action

For a specific noise problem, Table 3 (see below) may be used to select different actions.

## 4.8 Recommended Practices

NEF/NEP contours should be used in conjunction with these guidelines to encourage compatible land use in the vicinity of aerodromes. Therefore, it is recommended that contours be distributed by aerodrome operators or airport authorities to the officials and organizations responsible for land use and municipal zoning of the affected land. This would normally include both provincial and municipal planners, and zoning boards.

## Table 1 - Community Response Prediction

Response Area Response Prediction *

1 (over 40 NEF)

Repeated and vigorous individual complaints are likely. Concerted group and legal action might be expected.

2 (35-40 NEF)

Individual complaints may be vigorous. Possible group action and appeals to authorities.

3 (30-35 NEF)

Sporadic to repeated individual complaints. Group action is possible.

4 (below 30 NEF)

Sporadic complaints may occur. Noise may interfere occasionally with certain activities of the resident.

* It should be noted that the above community response predictions are generalizations based upon experience resulting from the evolutionary development of various noise exposure units used by other countries. For specific locations, the above response areas may vary somewhat in accordance with existing ambient or background noise levels and prevailing social, economic and political conditions.

## Table 2 - Land Use Tables - Aircraft Noise Considerations Only

This land use tabulation should not be considered as an exhaustive listing, but merely as examples of how various land uses would be assessed in the Noise Exposure Forecast zones in terms of community response predictions.

NO - Indicates that new construction or development of this nature should not be undertaken.

NO - Indicates that new construction or development of this nature should not be undertaken. See Explanatory Note B.

A - This particular land use may be acceptable in accordance with the appropriate note and subject to the limitations indicated therein.

YES - The indicated land use is not considered to be adversely affected by aircraft noise and no special noise insulation should be required for new construction or development of this nature.

The land uses contained in the following tables are included for compatibility purposes from a noise perspective only. Caution should be exercised as some of the recommended uses may not be optimal from a safety perspective (i.e bird and wildlife habitat)

### Table 2A - Residential

Noise Exposure Forecast Values >40 40-35 35-30 < 30
Response Areas 1 2 3 4
Detached, Semi-Detached NO NO NO A
Town Houses, Garden Homes NO NO NO A
Apartments NO NO NO A

### Table 2B- Recreational - Outdoor

Noise Exposure Forecast Values >40 40-35 35-30 < 30
Response Areas 1 2 3 4
Athletic Fields NO J K YES
Theatres - Outdoor NO NO NO H
Racetracks - Horses NO K K YES
Racetracks - Autos YES YES YES YES
Fairgrounds K K YES YES
Golf Courses YES YES YES YES
Beaches and Pools YES YES YES YES
Tennis Courts NO K YES YES
Playgrounds K K YES YES
Marinas YES YES YES YES
Camping Grounds NO NO NO NO
Park and Picnic Areas NO K YES YES

### Table 2C - Commercial

Noise Exposure Forecast Values >40 40-35 35-30 < 30
Response Areas 1 2 3 4
Offices F E D YES
Retail Sales F D YES YES
Restaurants F D D YES
Indoor Theatres NO G D YES
Hotels and Motels NO F G YES
Parking Lots YES YES YES YES
Gasoline Stations YES YES YES YES
Warehouses YES YES YES YES
Outdoor Sales E K YES YES

### Table 2D - Public

Noise Exposure Forecast Values >40 40-35 35-30 < 30
Response Areas 1 2 3 4
Schools NO NO D C
Churches NO NO D C
Hospitals NO NO D C
Nursing Homes NO NO D C
Auditoriums NO NO D C
Libraries NO NO D C
Community Centres NO NO D C
Cemeteries N N N N

### Table 2E - Municipal Utilities

Noise Exposure Forecast Values >40 40-35 35-30 < 30
Response Areas 1 2 3 4
Electric Generating Plants YES YES YES YES
Gas & Oil Storage YES YES YES YES
Garbage Disposal YES YES YES YES
Sewage Treatment YES YES YES YES
Water Treatment YES YES YES YES
Water Storage YES YES YES YES

### Table 2F - Industrial

Noise Exposure Forecast Values >40 40-35 35-30 < 30
Response Areas 1 2 3 4
Factories I I YES YES
Machine Shops I I YES YES
Rail Yards YES YES YES YES
Ship Yards YES YES YES YES
Cement Plants I I YES YES
Quarries YES YES YES YES
Refineries I I YES YES
Laboratories NO D YES YES
Lumber Yards YES YES YES YES
Saw Mills I I YES YES

### Table 2G - Transportation

Noise Exposure Forecast Values >40 40-35 35-30 < 30
Response Areas 1 2 3 4
Highways YES YES YES YES
Shipping Terminals YES YES YES YES
Passenger Terminals D YES YES YES

### Table 2H - Agriculture

Noise Exposure Forecast Values >40 40-35 35-30 < 30
Response Areas 1 2 3 4
Crop Farms YES YES YES YES
Market Gardens YES YES YES YES
Plant Nurseries YES YES YES YES
Tree Farms D YES YES YES
Livestock Pastures M YES YES YES
Poultry Farms L L YES YES
Stockyards M YES YES YES
Dairy Farms M YES YES YES
Feed Lots M YES YES YES
Fur Farms K K K K

### Explanatory Notes for Table 2

The location of the lines between noise zones cannot be fixed exactly. It will therefore be necessary for the responsible public authority to make an appropriate interpretation of what regulations are to apply at a specific location.

In cases where reference is made to a detailed on-site noise analysis, or to peak noise levels, it will be appreciated that the notes are intended to apply specifically at existing aerodromes, where a field assessment is possible. For planning with respect to new aerodromes, such zones should be considered cautionary. Before reaching a final decision with respect to permitting the particular land-use in question, the authority may wish to consider local topographic effects and ambient noise levels, in conjunction with generalized peak noise level "footprints" for the predominant aircraft types to be using the newaerodrome.

A

Annoyance caused by aircraft noise may begin as low as NEF 25. It is recommended that developers be made aware of this fact and that they undertake to so inform all prospective tenants or purchasers of residential units. In addition, it is suggested that development should not proceed until the responsible authority is satisfied that acoustic insulation features, if required, have been considered in the building design.

B

(b) This Note applies to NEF 30 to 35 only. New residential construction or development should not be undertaken. If the responsible authority chooses to proceed contrary to Transport Canada's recommendation, residential construction or development between NEF 30 and 35 should not be permitted to proceed until the responsible authority is satisfied that:

• (1) appropriate acoustic insulation features have been considered in the building and
• (2) a noise impact assessment study has been completed and shows that this construction or development is not incompatible with aircraft noise.

Notwithstanding point 2, the developer should still be required to inform all prospective tenants or purchasers of residential units that speech interference and annoyance caused by aircraft noise are, on average, established and growing at NEF 30 and are very significant by NEF 35.

C

These facilities should not be located close to the 30-NEF contour unless the restrictions outlined in Note D below are applied.

D

These uses should not be approved unless a detailed noise analysis is conducted and the required noise insulation features are considered by the architectural consultant responsible for the building design.

E

When associated with a permitted land use, an office may be located in this zone provided that all relevant actors are considered and a detailed noise analysis is conducted to establish the noise reduction features required to provide an indoor environment suited to the specific office function.

F

It is recommended that this specific land use should be permitted only if related directly to aviation-oriented activities or services. Conventional construction will generally be inadequate and special noise insulation features should be included in the building design.

G

Generally, these facilities should not be permitted in this zone. However, where it can be demonstrated that such a land use is highly desirable in a specific instance, construction may be permitted to proceed provided that a detailed noise analysis is conducted and the required noise insulation features are included in the building design.

H

Facilities of this nature should not be located close to the NEF 30 contour unless a detailed noise analysis has been conducted.

I

Many of these uses would be acceptable in all NEF zones. However, consideration should be given to internally generated noise levels, and acceptable noise levels in the working area.

J

Undesirable if there is spectator involvement.

K

It is recommended that serious consideration be given to an analysis of peak noise levels and the effects of these levels on the specific land use under consideration.

L

The construction of covered enclosures should be undertaken if this use is to be newly introduced to the noise environment. (See Note M below).

M

Research has shown that animals condition themselves to high noise levels. However, it is recommended that peak noise levels be assessed before this use is allowed.

N

This appears to be a compatible land use in all NEF zones.

## Table 3 - Recommended Matrix of Noise Control Actions

 Consider these actions If you have this problem Noise from taxiing Departure Approach Landing roll Training flights Maintenance Changes in runway location, length or strength ▪ column selected ▪ column selected ▪ column selected ▪ column selected ▪ column selected Displaced thresholds ▪ column selected ▪ column selected High-speed exit taxiways ▪ column selected ▪ column selected Relocated terminals ▪ column selected ▪ column selected ▪ column selected Isolating maintenance runups or use of test stand noise suppressors and barriers ▪ column selected ▪ column selected ▪ column selected * Preferential or rotational runway use ▪ column selected ▪ column selected ▪ column selected ▪ column selected ▪ column selected * Preferential flight track use or modification to approach and departure procedures ▪ column selected ▪ column selected ▪ column selected * Restrictions on ground movement of aircraft ▪ column selected Restrictions on engine runups or use of ground equipment ▪ column selected ▪ column selected Limitations on number or types of operations or types of aircraft ▪ column selected ▪ column selected ▪ column selected ▪ column selected ▪ column selected ▪ column selected ▪ column selected US restrictions, rescheduling move flights to another aerodrome ▪ column selected ▪ column selected ▪ column selected ▪ column selected ▪ column selected ▪ column selected ▪ column selected Raise glide slope angle or intercept. ▪ column selected ▪ column selected Power and flap management ▪ column selected ▪ column selected ▪ column selected Limited use of reverse thrust ▪ column selected Land or easement acquisition ▪ column selected ▪ column selected ▪ column selected ▪ column selected ▪ column selected ▪ column selected ▪ column selected Joint development of aerodrome property ▪ column selected ▪ column selected ▪ column selected ▪ column selected ▪ column selected ▪ column selected ▪ column selected Compatible use zoning ▪ column selected ▪ column selected ▪ column selected ▪ column selected ▪ column selected ▪ column selected ▪ column selected Building code provisions and sound insulation of buildings ▪ column selected ▪ column selected ▪ column selected ▪ column selected ▪ column selected ▪ column selected ▪ column selected Real property noise notices ▪ column selected ▪ column selected ▪ column selected ▪ column selected ▪ column selected ▪ column selected Purchase assurance ▪ column selected ▪ column selected ▪ column selected ▪ column selected ▪ column selected ▪ column selected Noise related landing fees ▪ column selected ▪ column selected ▪ column selected ▪ column selected ▪ column selected Noise monitoring ▪ column selected ▪ column selected ▪ column selected ▪ column selected Establish citizen complaint mechanism ▪ column selected ▪ column selected ▪ column selected ▪ column selected ▪ column selected ▪ column selected ▪ column selected Establish community participation program ▪ column selected ▪ column selected ▪ column selected ▪ column selected ▪ column selected ▪ column selected ▪ column selected

* These are examples of restrictions that involve TC Aviation's responsibility for safe implementation.

## Footnotes

Footnote 1

Kingston, Beaton and Rohr, A Description of the CNR and NEF Systems for Estimating Aircraft Noise Annoyance (R-71-20), Department of Transport, 1971

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