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Design for ears - acoustics and finishes

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Design for ears - acoustics and finishes

I can’t hear myself think is no longer a throwaway line. We have a growing population living closer together; hard surface flooring in cafes, restaurants and homes; open-plan offices; school classrooms where speech is unintelligible with too high a reverberation time.

At a recent TED talk, sound expert Julian Treasure, lamented the lack of designing for ears. He urged architects to consider acoustic treatments, placement of products away from noise, and to create a new profession of urban sound planners.

His talk was one of the Sound Education seminars about sound and acoustics and their influence on teaching and learning that Ecophon acoustic ceilings is bringing out. London architect Richard Mazuch calls it “invisible architecture”, a phrase with which Treasure and Brian Clarke, Senior Associate at acoustic consultants Wilkinson Murray, can identify.

“Designing for experience, not appearance, to have spaces that sound as good as they look, that improve our health, wellbeing, social behavior and productivity,” is Treasure’s maxim.

Products and materials and design techniques are available both for improving how a room sounds “where products are chosen to improve the aural experience in a space”, says Clarke, and “sound isolation between spaces where materials have mass and stop sound transfer or intrusion to occupied areas”.

Where there are informed clients and skilled, interested architects, customised solutions can prevail, such as with BVN Architecture, who used Good Environmental Choice Australia-certified rubber matting underlays and polyester batts in ceilings behind perforated panels to absorb sound at Ravenswood school.

Renders of the Alessi apartments, designed by architecture practice Elenberg Fraser, which are being developed in Melbourne.

 

At West Melbourne Alessi apartments, due for completion 2014, Elenberg Fraser is developing a “nurturing building” with South American tripartite layering including a deep façade with white concrete waffled brise soleils sheltering interiors from the double-glazed frontage; and laser-cut aluminium screens on the upper level for extra shade and privacy. “Design is all about finding the best product for its application,” says Elenberg Fraser Associate, Reade Dixon.

Acoustics for restaurants, on the other hand, “are often an afterthought, but are increasingly being integrated into the design”, says Kori Todd, of Woods Bagot Interior Design. But that has not stopped market demands leading to more stylised and integrated products benefitting from advanced technologies and materials. (Incidentally, Woods Bagot gave the existing dome ceiling at their new Pony restaurant in Brisbane an acoustic treatment.)

“It is not just the products that determine the end result vis a vis the acoustic performance,” says Acoustica Marketing Manager Isabel de Oliveira. “It is the entire structure of the building, and its components.” For instance, the company’s QuietWave drywall noise barriers (Rw  62 and Rw+Ctr 55 dB), 148 mm thick with 64 mm studs in a 90mm track, are promoted as reducing wall width compared to other soundproof panels, thereby reducing the footprint of applications from home entertainment theatres to function centres.

Pony restaurant in Brisbane, designed by Woods Bagot. Photography: Trevor Mein.

The panels meet Association of Australian Acoustical Consultants’ six stars rating, just one of the measures to watch out for since the 2004 tightening of Building Code of Australia (BCA) requirements in section F5 – sound transmission and insulation. The current performance requirement (classes 1, 2, 3 and 9c) of Rw+Ctr ≥50 contains the correction factor Ctr to reduce low frequency noise, says Mark Debevc, Manager – Acoustic Systems at Boral.

Local authorities also set acoustic performance requirements, says Nick Holden, Managing Director, Modular Wall Systems, recently stipulating acoustic performance in fencing applications. The company’s staple external wall panel, the AcoustiMax, reduces traffic noise by 25 dB from one side of a wall to the other as long as length and height requirements are met, Holden says.

Brick acoustic solutions apply to transmitted sound in walls, says Chris Mouatt, Boral Clay and Concrete’s National Technical Manager. The sound attenuation (the intensity at which sound is transmitted from one point to another) is related to its mass; its thermal stability rather than acoustic performance as such.”

Everyone agrees that acoustic performance is not affected by colour so in choosing products in one of the major acoustic areas, plasterboard (perforated and non-perforated) and plywood linings for internal walls and ceilings, that is not a differentiating factor. Most are pre-finished, fire, acoustic, impact and moisture resistant, made to install over other wall or ceiling surfaces, or for direct fixing onto ceilings or walls.

There are modular ranges suitable for ceiling refurbishments with ceiling grids in place, or panels to give full access to the ceiling cavity, or interlocking panels on folding track systems such as the Gyprock StrataWall, and slotted, sound absorbent strips such as the Elton Group’s AP Topakustik acoustic panelling for ceiling and walls.

Look out for the latest additions such as the impact, moisture and mould resistance of Gyprock EC08 Complete, or Bradford Insulation’s New Generation SoundScreen, which now comes in fully sealed packs with more batts per pack. Testing over three common wall systems also showed improvements of around 1Rw, and up to 1.8 Rw over the traditional SoundScreen product.

Exclusive Australian distributor for the Ecophon range of glasswool, moisture resistant, recyclable ceiling systems, Ceilector Ceiling Solutions covers ceiling tiles, grids and accessories of mineral fibre, metal and high acoustic. Marketing Manager, Emma Young, says, “Ecophon products have an NRC (Noise Reduction Co-efficient), or average sound absorption of a ceiling, of 0.95 and 1 (though most fall between 0.75 and 0.95).” Young compares this with 0.50 the value that starts to contribute some entry level noise benefits.

Ceilector plans to add timber ceiling options in 2013, she says.

Carpet is the only floor covering deemed to comply with the Australian Building Regulations with no requirement to produce acoustic testing evidence, says Graham Caldwell at Karndean Designflooring. Timber flooring, for instance, requires acoustic underlays such as Dunlop Flooring’s Timbercushion, which is particularly suitable for multi-storey applications. There are carpet underlays such as ones from Tontine (distributed by Airstep) including the Superfelt range, made from natural materials and recycled textiles, and biodegradable. Tontine acoustic insulation range is GreenTag certified polyester.

Caldwell says Karndean’s luxury vinyl tiles and planks will have its own built-in acoustic underlay called LooseLay. BCA criteria for impact sound reaching a space via the ceiling/floor overhead is set at 62dB or less, he says, and LooseLay achieves 59dB without added underlay.

Timber, aluminium and uPVC acoustic windows and doors are reliable performers, with glazing for high traffic areas, or energy saving, noise reducing insulation, or specific noise resistant glass (as from Viridian), and double-glazing varieties with air space at appropriate distances between the two windows acting as a noise barrier. Magnetite has retrofit double glazing. Existing windows do not need to be replaced, and the system’s magnetic seal both eliminates draughts and reduces noise.

Other products have acoustic potential such as the moulded fibre composites that Managing Director, Norm Watt, says the BAC (Advanced Composites) Group can shape almost infinitely with the fibre composite layers separated by a foam core that provides rigidity. The foam generally has very good acoustic properties, he says, though they would vary depending on the core’s thickness and density.

And Dulux Australia expects to release a new coating this year that Dulux Brand Manager Trade, Amanda Chalmers says “will help improve the acoustic performance of both new and refurbished rooms. Dulux Australia is working with acoustic experts.

“This is the first time a coating has been tested and verified to both ISO and Australian standards to deliver the performance demanded by the BCA to meet consumer expectations for an acoustic solution,” she says.

For more, listen to this space.

 

This article appeared first in BPN Magazine, February 2012.


 

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