Appendix A—The Australian Noise Exposure Forecast (ANEF) System
The ANEF system was developed through a major socio-acoustic survey carried out in the vicinity of a number of Australian airports in 1980 (see the report cited at [ref 3]). Based on the results of this work the system then in use in Australia—the NEF system—was modified to suit Australian conditions and became termed the ANEF system. The ANEF system incorporated a weighting for the period 7pm to 7am (as opposed to the 10pm to 7am period under the NEF system) as the study showed that this gave the best correlation between noise dose and community reaction.
The ANEF is an equal energy noise index similar to the Ldn and Leq. ANEF is generally taken to be approximately equivalent to Leq—35. A sample ANEF contour is shown in Figure A.1.
The ANEF system was developed as a land use planning tool aimed at controlling encroachment on airports by noise sensitive buildings. The system underpins Australian Standard AS2021 ‘Acoustics—Aircraft noise intrusion—Building siting and construction’. The Standard contains advice on the acceptability of building sites based on ANEF zones.
The acceptability criteria vary depending on the type of land use. However, the most crucial criterion for the purposes of this paper specifies that land with an aircraft noise exposure level of less than 20 ANEF is acceptable for the building of new residential dwellings.
The line for acceptability of residential building construction was drawn at 20 ANEF as this corresponded to the 10% ‘seriously affected’ level in the dose/response relationship established by the 1980 study mentioned in Section A.1.
There a three different forms of contour maps recognised under the ANEF system.
These are the official forecasts of future noise exposure patterns around an airport and they constitute the contours on which land use planning authorities base their controls.
These are contours showing historic noise exposure patterns and are used in environmental reporting and benchmarking.
These are scenario contours and are used to produce ‘what if’ contours, for example, in the process of examining flight path options around an airport.
In order to aid clarity the term ‘ANEF’ is generally used throughout the paper when referring to any of the above three types of contour.