Noise barrier suppliers
We do not have preferred barrier suppliers and do not recommend any particular barrier products. The following list is provided as a guide to the range of barrier types that are available. The acoustics ratings are explained here, and items with an asterisk are estimates only.
Material / Product | Image | Built locations | Acoustics rating | ||
A | B | D | |||
Timber | |||||
Modular engineered plywood wall system. It can be built over 6 m high. Manufacturer's test data: |  | SH20, Maioro Street Interchange, Auckland (2011) SH18, Greenhithe, Auckland (2007) | A0 | B2* | D3 1 |
Panels composed of woodwool impregnated with rapid hardening cement, under pressure. Manufacturer's test data shows the panels provide sound absorption in the order of 0.6 NRC. |  |
| A2* | B2* |
|
Timber wall system with reflective and absorptive panel options. Absorptive panel Reflective panel |  |
|
A3 A0 |
B3 B3 |
|
Concrete | |||||
Pre-cast concrete Modular system, usually with steel support posts. Pumice aggregate and induced air entrainment reduces the weight of panels. Panels are 150 mm thick up to a maximum size of 7 m x 3.5 m. |
| Mt Hobson Road, Newmarket, Auckland (2010) | A0 | B3* |
|
Pre-cast concrete Modular system, usually with steel support posts. Panels can span up to 8 m. Precast concrete panels with 25% recycled concrete. Acoustics test data available from the manufacturer. |  | SH1, Otahuhu, Auckland (2010) | A0 | B3* |
|
Pre-cast concrete Modular wall panel. Panels are a mix of cement, limestone, cellulose fibre and additives, with hollow cores to reduce weight. Panels are 300 mm wide and up to 2.2 m long. |  | No specific noise barrier examples to date, but has been used as a fencing product within NZ. VicRoads (the highway authority for the Australian State of Victoria) has advised that the use of these panels in noise barriers in some VicRoads projects has not been successful. | A0 | B3 |
|
Pre-cast concrete Modular system, usually with steel support posts. Panels made from Autoclaved Aerated Concrete (AAC). 600 mm high by 100 mm thick panels are stacked horizontally and attached by clip and bolt to support posts. Panels available up to 6 m long and to heights exceeding 4 m. |  | Noise barrier at Martha Mine, Waihi, NZ | A0 | B3* |
|
Pre-cast concrete An interlocking barrier system made with Hebel AAC panels that slide down into reinforced concrete or steel posts. Panels are 600mm wide & up to 2.2m long. |  | Greenlane railway, Auckland | A0 | B3* |
|
Pre-cast concrete A combination of recycled rubber and concrete precast panels 150mm thick. The recycled tyres provide sound absorption. It is a modular system with steel support posts at 3-5 metre centres. |  |
| A2 | B3 |
|
Pre-cast concrete A combination of recycled timber and concrete precast panels 150mm thick. The recycled timber provides sound absorption. It is a modular system with steel support posts at 3-5 metre centres. |  |
| A3 | B3 |
|
Transparent | |||||
Acrylic panel. Bird guard product includes 2 mm wide black stripes at 30 mm spacings within panel. |  | SH1, Victoria Park Tunnel project, Auckland (2011) | A0 | B3 | D4 1 |
Lightweight modular aluminium frame with acrylic insert (12-20 mm thick), available in various lengths and heights. Can be provided with cast-in polyamide strips and anti-graffiti coating. Reflective and absorptive panels also available. |  | Installed in several locations in Europe | A0 | B3 |
|
Acrylic panel. Can be provided with clear, coloured or matt finishes, along with an anti-graffiti coating.
|  |
| A0 |
|
|
Composite | |||||
Panels formed from zinc coated steel shell filled with aerated concrete. Modular interlocking panels which can be installed horizontally or vertically. |  | No specific noise barrier examples, but to date have been used for building sound insulation purposes within NZ e.g. cinemas, apartments | A0 | B3* |
|
Frabricated plastic noise walls with support columns. Interlocking panels and mounting posts. |  | No specific noise barrier examples to date, but have been used commercially as an alternative to steel within NZ. | A0 | B3* |
|
Sandwich panel consisting of a foam core and two reinforced resin laminated outer skins with steel or concrete support posts |  | No specific noise barrier examples to date, but has been used as a fencing product within NZ | A0 | B2* |
|
Panels formed from fibre cement skins with polystyrene core. A modular system with panels fitting in slotted steel posts (280 mm wide by 140 mm deep). Composite panels are 70 mm thick, in heights of 900 or 1200 mm and lengths of 2400, 2700 or 3000 mm. Manufacturer's test data: AS 1191-2002. |  | Residential and commercial sites in the main centres in NZ. Noise barriers for the New South Wales Roads & Traffic Authority. | A0 | B2 |
|
Lightweight modular aluminium panels available in various lengths and heights. Reflective, absorptive and transparent panel options. Internal rock wool (approximately 40 mm thick) for added sound insulation / absorption. Can be provided with anti-graffiti coating. Absorptive panel Reflective panel |  | Installed in several locations in Europe |
A4 A0 |
B3 B3 |
|
Lightweight aluminium panels provide either single or double side sound absorption. Perforation patterns and panel infill material can be varied to suit requirements. |  |
| A3 | B3 |
|
Other | |||||
Steel mesh cage filled with rocks, with an acoustic blanket lining. Factory filled and vibrated, double galvanised gabion with an integrated lifting system. 80 mm thick acoustic blanket embedded in the cage. |  | No specific noise barrier examples to date, but has been used within retaining walls NZ | A0 | B3* |
|
Sheets made from recycled paper impregnanted with bitumen, corrugated on one side. A separate timber frame is required. Manufacturer recommends cladding both sides of the frame for acoustics performance. |  | No specific noise barrier examples to date, but has been used as roofing, wall cladding, fencing within NZ | A0 | B2* |
|
1 Data derived from 'Measurements of the Acoustic Performance of Traffic Noise Barriers on Auckland Motorways Using prEN1793-6:2011Measurements of the Acoustic Performance of Traffic Noise Barriers on Auckland Motorways Using prEN1793-6:2011', University of Canterbury, 2012.
Performance ratings
Sound absorption
The 'A' rating is defined in EN 1793-1 and relates to the sound absorbed by a barrier that would be otherwise reflected. In effect, A0/A1 means most sound is reflected, through to A4 which means most sound is absorbed. This can be significant when there are tall parallel barriers facing each other, and sound reflected from the far barrier can pass over the near barrier. The EN 1793 absorption categories are defined in the following table.
Category | DL α |
A0 | N/A |
A1 | < 4 dB |
A2 | 4 to 7 dB |
A3 | 8 to 10 dB |
A4 | > 11 dB |
Sound transmission
Laboratory
The 'B' rating is defined in EN 1793-2 and related to the reduction of sound passing through a barrier. B0/B1 means that the barrier is not effectively reducing sound through the barrier, through to B3 which provides the most sound reduction. (The overall performance will also be highly dependent on the barrier height.) These ratings are currently tested in a laboratory under reverberant sound conditions. The EN 1793 sound transmission categories are defined in the following table.
Category | DL R |
B0 | Not determined |
B1 | < 15 dB |
B2 | 15 to 24 dB |
B3 | > 24 dB |
Where the DL R performance has not been stated by the manufacturer/supplier, the following process has been use to estimate its value.
- 1/3 octave band sound reduction index data has been used where available.
- If the only data available is a single figure Rw/STC, the spectrum has been estimated using Insul software program and scaled to the quoted Rw/STC.
- If no acoustics value is stated, Insul has been used to estimate the properties, and a 2 dB tolerance subtracted from the performance
- Where the test has not included a post, this has been modelled with 3 mm wide leakage path running the full height of the barrier, as modelled in Insul using Gomperts' method
Field
The 'D' rating is defined in EN 1793-6 and is a field rating which represents the reduction of sound passing through the barrier actually achieved. The field sound transmission categories are defined in the following table.
Category | DL SI,G |
D0 | Not determined |
D1 | < 16 dB |
D2 | 16 to 27 dB |
D3 | 28 to 36 dB |
D4 | > 36 dB |
For further information contact environment@nzta.govt.nz .