Airport noise contours: ANEF, ANEC, N-contours and AS 2021 for residential

TL;DR

If your lot sits within a council’s airport noise overlay, you are inside an ANEF contour and AS 2021-2015 applies to your build. Below 20 ANEF: no special treatment needed. Between 20 and 25 ANEF: conditionally acceptable, acoustic treatment required. Above 25 ANEF: unacceptable for new residential, most councils refuse consent. The treatment costs real money and ordinary laminated safety glass does not satisfy the standard. Get an acoustic consultant’s report before you draw, not after your window schedule is locked.

What this article is for

Airport noise overlays catch residential builders off guard more often than any other environmental overlay. Unlike bushfire or flood, there is no visible site feature that tells you you’re in the zone. You find out from a planning certificate, a council pre-DA response, or a private certifier who flags it on the way to a CDC.

This article explains the three noise metrics used in Australian planning (ANEF, ANEC, N-contours), how AS 2021-2015 translates those metrics into building requirements, where the overlays currently apply across Australian states, and the practical builder gotchas that turn a routine Class 1a into an expensive compliance exercise.

ANEF vs ANEC vs N-contours

Three different metrics appear in planning documents. They measure different things and carry different planning weight.

Metric	What it measures	Planning status	Who endorses it
ANEF (Australian Noise Exposure Forecast)	Cumulative annual average daily noise exposure from all forecast aircraft movements at an airport. A composite index weighted to penalise night operations (night flights multiplied by four). Expressed as a single number (e.g. 20, 25, 30).	Formally endorsed planning instrument. State and local planning schemes apply ANEF contours directly as overlays.	Airservices Australia, under Ministerial Direction M37/99.
ANEC (Australian Noise Exposure Concept)	Uses the same composite index as ANEF but represents a hypothetical or scenario-based forecast before formal endorsement. An ANEC is the “what if” version, for example, showing noise exposure under an alternative flight path arrangement.	Not a formal planning instrument on its own. Sometimes cited in state planning policies during airport expansion planning before a final ANEF is endorsed. In NSW, the Aerotropolis SEPP has used ANEC contours as interim controls while the Western Sydney Airport ANEF is finalised.	Not formally endorsed by Airservices. Produced by airports or government as scenario inputs.
N-contours (Number-above contours)	Count of single aircraft noise events exceeding a stated threshold per day. N70 = events exceeding 70 dB(A) outdoors per day. N60 = events exceeding 60 dB(A) per day. These are separate from ANEF and show event frequency rather than cumulative annual exposure.	Supplementary metric. Used in community reporting and EIS documents but not the primary planning trigger. N70 is significant because 70 dB(A) outdoors typically produces around 60 dB(A) indoors with windows closed, the indoor design target under AS 2021 for living areas. N60 is the night benchmark (50 dB(A) indoor, the sleep disturbance threshold).	Produced by airports and Airservices using FAA Aviation Environmental Design Tool (AEDT). Not independently endorsed.

The planning trigger is nearly always the ANEF. If an ANEF contour is drawn on a council planning map, it has been technically endorsed by Airservices and is a statutory overlay. ANEC contours are interim and may or may not appear in your LEP or planning scheme depending on the state and airport. N-contours appear in EIS documents and community reports but rarely trigger building treatment requirements directly.

AS 2021 land-use compatibility

AS 2021-2015 sets the national framework for managing aircraft noise in buildings. Its land-use compatibility table divides residential development into three categories based on ANEF zone.

ANEF zone	Category for residential	Implication
Below 20 ANEF	Acceptable	No specific aircraft noise treatment required. Standard residential construction is appropriate.
20 to 25 ANEF	Conditionally Acceptable	Residential permitted but must comply with AS 2021 acoustic construction requirements. A consent condition or building permit condition will typically require an acoustic consultant’s report and compliant construction.
Above 25 ANEF	Unacceptable	New residential development is not recommended by the standard. Most state planning schemes reflect this as a prohibition or require ministerial discretion. New dwellings are generally refused consent inside the 25 ANEF contour.

Note: the ANEF thresholds in AS 2021 for residential are tighter than for some other uses. Hotels, for instance, are conditionally acceptable up to 30 ANEF. Industrial land uses can be acceptable well above 30 ANEF. Residential is among the most noise-sensitive categories in the table.

A subset of existing dwellings sits inside the 25 ANEF contour because those houses predate the overlay or were approved before planning controls caught up. The standard provides guidance for upgrading existing buildings in these zones, but pre-existing dwellings are typically not required to retrofit unless they are substantially renovated.

Acoustic insulation requirements by zone

For development in the 20 to 25 ANEF zone, AS 2021-2015 requires the building to achieve indoor design noise levels that protect occupants from aircraft flyovers. The standard specifies:

Living areas (habitable rooms excluding bedrooms): Maximum indoor Leq (equivalent continuous noise level) of 55 dB(A) and maximum indoor Lmax (single event peak) of 60 dB(A).
Sleeping areas (bedrooms): Maximum indoor Leq of 50 dB(A) and maximum Lmax of 60 dB(A).

To achieve those levels, the building envelope must be treated. The specific construction requirements depend on the modelled outdoor noise levels at the site, which an acoustic consultant calculates using the endorsed ANEF data for that airport.

Typical treatment for a site in the 20 to 25 ANEF zone:

Glazing: Standard 6.38mm laminated safety glass (the minimum safety-glass product) is usually insufficient. AS 2021 requires glazing that achieves a minimum weighted sound reduction index (Rw) matched to the outdoor aircraft noise level. In practice this typically means 6.38mm acoustic laminated glass with a PVB interlayer designed for acoustic performance, or double-glazed units (IGU) with asymmetric pane thickness. The acoustic PVB interlayer is the critical specification: ordinary laminated glass uses the same PVB product as safety glass but the PVB is not formulated to suppress mid-frequency noise, which is where aircraft noise is most intrusive. An acoustic consultant must specify glazing by Rw rating, not by laminate thickness alone.

Walls: External walls facing noise-sensitive directions typically require insulation within the stud cavity (R2.5 minimum glasswool or equivalent), plasterboard lining of at least 13mm on the internal face, and no gaps around penetrations. Masonry construction generally has adequate mass. Lightweight framed walls need detailing around windows and doors to avoid flanking.

Roof and ceiling: Aircraft noise arrives from above. Ceiling treatment is often the highest-cost element. Requirements typically include: bulk insulation of at least R3.5 in the ceiling cavity, a continuous plasterboard ceiling (no cornices with gaps to the roof cavity), and careful sealing of exhaust fan and downlight penetrations. Tiled roofs provide less attenuation than metal roofing with sarking; the ceiling below carries most of the load.

Ventilation: Sealed construction to achieve acoustic performance conflicts with natural ventilation. AS 2021 does not require fully sealed buildings, but any openable window that is used for ventilation will bypass the acoustic treatment when open. Mechanical ventilation (MVHR or split system) is often the pragmatic solution for sleeping areas.

Where airport noise overlays apply

Airport noise overlays appear in state planning schemes around all major capital city airports and many regional airports. The form of the overlay differs by state but the underlying ANEF contours are consistent.

State	Overlay instrument	Major airports with ANEF overlays
NSW	ANEF contours in individual LEPs; ANEC contours in the Western Sydney Aerotropolis SEPP for WSINT. Residential generally refused consent inside the 20 ANEF contour (some LEPs use 25)	Sydney (Kingsford Smith), Western Sydney International (Badgerys Creek), Newcastle, Canberra (ACT), regional airports including Albury, Orange
VIC	Airport Environs Overlay (AEO) and Melbourne Airport Environs Overlay (MAEO) in the Victoria Planning Provisions, applied via individual planning schemes	Melbourne (Tullamarine), Avalon, Essendon, regional airports including Ballarat, Latrobe Valley
QLD	Airport Environs Overlay in local planning schemes	Brisbane, Gold Coast, Cairns, Townsville, Sunshine Coast, Rockhampton
WA	State Planning Policy 5.1 (vicinity of Perth Airport) and individual local planning schemes	Perth, Jandakot
SA	Aircraft Noise Exposure Overlay in the Planning and Design Code	Adelaide
TAS	Noise overlays in Local Provisions Schedules	Hobart, Launceston
ACT	Territory Plan noise controls around Canberra Airport	Canberra
NT	NT Planning Scheme controls around Darwin Airport	Darwin

The 20 ANEF contour is typically the outer boundary of planning control. Inside that line, councils apply various levels of restriction from requiring acoustic treatment up to full prohibition on new residential.

Check your council’s planning portal or the relevant airport’s master plan for the current endorsed ANEF map. Airservices Australia publishes endorsed ANEFs at airservicesaustralia.com (verified 2026-05-23). Individual airports also publish their ANEFs in their master plans, which are lodged with the federal Department of Infrastructure.

Disclosure at title

In NSW, the Section 10.7 planning certificate (the certificate you get from council before exchange of contracts) must disclose if a lot is within an ANEF or ANEC contour of 20 or above. This disclosure appears in the relevant zoning and controls section of the certificate and is one of the primary conveyancing flags for buyers and their solicitors. See Section 10.7 certificates: what they reveal and how to read them.

Other states handle disclosure differently. In Victoria, the planning permit application triggers the MAEO/AEO notification. In Queensland, the airport environs overlay appears on the property’s zone certificate. In WA, State Planning Policy 5.1 requires the ANEF to be reproduced in the relevant local planning scheme, making it visible on council zoning certificates.

If you’re building for a client on a lot they purchased without advice, the absence of disclosure in a conveyancing certificate does not mean the lot is outside an overlay. The endorsed ANEF for an airport can be updated as the airport’s master plan is revised. It is always worth checking the current ANEF against the planning certificate, particularly for airports with recently updated master plans (Brisbane 2026, Gold Coast 2024, Western Sydney in draft).

What can go wrong

Specifying safety laminate as acoustic laminate. The two products look identical, have the same nominal thickness (commonly 6.38mm), and are both classified as safety glass under AS 1288. They are not interchangeable under AS 2021. Safety laminate PVB is optimised for post-breakage performance. Acoustic laminate PVB uses a different formulation that decouples pane vibration in the frequency range where aircraft noise is concentrated (typically 200 to 2000 Hz). Your glazing contractor’s quote for “6.38mm laminated glass” almost certainly means safety glass. Confirm the product by acoustic PVB specification, not by glass description.

Ignoring penetrations. A well-rated wall or ceiling with an unlined exhaust fan opening or a recessed downlight without an acoustic enclosure is acoustically worthless at that point. Aircraft noise intrudes through the weakest link. Every penetration in a noise-treated envelope needs a detail.

Budgeting for the floor area, not the treatment. The cost premium for AS 2021-compliant construction on a typical 200 sqm Class 1a in the 20 to 25 ANEF zone is commonly $15,000 to $25,000 above standard residential construction, driven primarily by upgraded glazing, ceiling treatment, and mechanical ventilation allowances. This is not a small margin item. If the client has a fixed budget and the lot is in an ANEF overlay, have the conversation about costs before design development.

Relying on a council pre-DA without a consultant report. Council planning officers can confirm whether the overlay applies. They cannot design your acoustic treatment. Some councils will not issue a DA consent without an AS 2021 assessment report. Get the acoustic report early; it scopes the construction spec and removes uncertainty from your window and ceiling schedule.

Assuming CDC path is available. Complying Development Certificates (CDCs) in NSW are not available on land identified within a 20 ANEF or higher contour under most SEPP provisions. Check the overlay before advising your client that CDC is an option.

Australian planning scheme structure explains which tier of instrument carries the airport noise overlay in each state (LEP in NSW, planning scheme overlay in VIC, planning scheme code in QLD and WA).
DCPs often contain supplementary acoustic design guidance that sits alongside the LEP ANEF controls in NSW councils adjacent to Sydney Airport.
Section 10.7 planning certificates in NSW is where you first read the ANEF disclosure for a NSW lot.
SEPPs in NSW explains the Aerotropolis SEPP and how ANEC contours around Western Sydney Airport are controlled at state level.

References

AS 2021-2015, Acoustics: Aircraft noise intrusion: Building siting and construction. Standards Australia, 2015. Available via SAI Global and ANSI webstore. Indoor design noise level criteria: Leq 50 dB(A) sleeping, 55 dB(A) living; Lmax 60 dB(A) all habitable rooms.
Airservices Australia, Australian Noise Exposure Forecasts and ANEIs, via airservicesaustralia.com (verified 2026-05-23). Ministerial Direction M37/99 requires Airservices to technically endorse all ANEF studies.
Department of Infrastructure, Transport, Regional Development, Communications and the Arts, ANEF System overview, Appendix A: The Australian Noise Exposure Forecast System, via infrastructure.gov.au (verified 2026-05-23).
Brisbane Airport Corporation, Australian Noise Exposure Forecast, Preliminary Draft 2026 Master Plan, via futurebne.bne.com.au (verified 2026-05-23). Five contour levels (20, 25, 30, 35, 40 ANEF); night operations weighted at four times daytime.
Planning Victoria, Aircraft noise controls including Airport Environs Overlay and Melbourne Airport Environs Overlay, via planning.vic.gov.au (verified 2026-05-23). New buildings within 20 to 25 ANEF and above must comply with AS 2021.
Western Sydney Airport fact sheet, Measuring aircraft noise: N-contours and ANEF explained, via westernsydneyairport.gov.au (verified 2026-05-23). N70 events correspond to 60 dB(A) indoor equivalent; N60 events correspond to 50 dB(A) indoor threshold relevant to sleep disturbance.
Airservices Australia, Considering aircraft noise when buying or building a home, via airservicesaustralia.com (verified 2026-05-23).
Gold Coast Airport, Noise Information including ANEF endorsed 5 July 2024, via goldcoastairport.com.au (verified 2026-05-23).
WA State Planning Policy 5.1: Land use planning in the vicinity of Perth Airport, via wa.gov.au (verified 2026-05-23).

TL;DR

What this article is for

ANEF vs ANEC vs N-contours

AS 2021 land-use compatibility

Acoustic insulation requirements by zone

Where airport noise overlays apply

Disclosure at title

What can go wrong

How to use this with related articles

References

Related

See also

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