In the midst of tough economic times, building professionals are today, more than ever, ensuring they get as much out of their building products as possible, and acoustic panels are no exception. Danielle Bowling reports.
Traditionally, acoustic panels have been used to control noise and quieten areas that typically generate a lot of noise, such as school halls and audito riums. They dampen noise with their porous surfaces, which sound waves can partially penetrate, getting trapped between the panel and the wall, rather than being fully reflected as they would by a smooth surface.
Nowadays, however, acoustic pan els are being increasingly used for their decorative potential as well as for their quietening effect.
Keystone Acoustics produces plas terboard, medium density fibreboard (MDF), fire-rated MDF and ply and fibre cement panels, custom-building them to architectural requirements. Keystone’s ply, fire-rated MDF and MDF panels can be painted or have a natural timber veneer applied to them, giving them a more aesthetical ly pleasing appearance.
“Architects and designers are actu ally using them not only for a func tional purpose, but for a decorative purpose at the same time,” says Michael Robbins, project manager at Keystone Acoustics. “We’re actually creating a pattern or writing a story. We've done one [project] where we engraved logos just by changing the size of the holes. Putting pictures in and things like that, means it actually becomes a feature panel as well as a decorative and functional panel.”
According to Robbins, the function of the panel also depends on whether it is made from a hard or soft fabric material. Hard panels are suitable for walkways, foyers, gyms, schools and other high traffic locations. Soft pan els have the acoustic material that does a lot of the absorption on the outside surface.
“If you have a small office space, they may put the hard acoustic panels in the ceiling because they will help support the lights,” Robbins says. “But they may put a soft acoustic panel on the walls and that fabric might have a pattern to it, so [again], it becomes a decorative piece at the same time.”
Keystone’s MDF acoustic panels were used in the ceiling of the Victor Chang Cardiac Research Institute at the St Vincent’s Centre for Applied Research in Sydney, designed by Daryl Jackson Robin Dyke (DJRD) Architects. The panels provided by Keystone were timber veneered, which prevented the area from looking too clinical, therefore pro moting congregation and interaction. Roughly 200 sqm of panels were used in the building’s ‘interaction areas’, including kitchenettes, meeting rooms, office spaces and communal meeting areas.
Associate at DJRD Architects, Jeevan Nangla, says that while func tionality was the prime concern when using acoustic panels at the Research Institute, aesthetics was also impor tant. He believes acoustic panels were the most appropriate material to use, primarily because of their ability to perform a number of key functions.
“We wanted to integrate lighting and we wanted to integrate acoustic absorbency and reflection of sound. We also wanted to create a point of difference in the colour scheme of the ceiling, so I think the choice of mate rial was correct,” he says.
Sustainability was also considered during the design of the project. The MDF panels used are one of the most eco-friendly fire-rated boards on the market — they are 80 per cent recyclable and have no added formaldehyde, making its environmental rating higher than E0, which is the current Australian standard.
Robbins has noticed a shift towards more envi ronmentally friendly building products, with sus tainability a growing concern for architects. It is appropriate, then, that a number of Keystone Acoustic panels are environmentally friendly.
“The fire-rated panel is FSC [Forest Stewardship Council] certified. The fibre-cement can be chewed up and recycled if they’re ever dismantled — same with the plasterboard. The ply is made from regrowth forests ... all of the materials, including the MDF, are coming from legal mills,” he says.
With a growing number of panels now on the market, selecting the right type can be difficult. Nereo Castelli from Total Noise Control believes that using a panel’s noise reduction coefficient (NRC) rating as the only criteria could be a mistake.
The NRC figure is an average of the absorption performance of a panel. The acoustic absorption of panels is tested at four frequency levels — 250 htz, 500 htz, 1,000 htz and 2,000 htz. The four results are then averaged and the final figure is the average absorption performance of the panel.
This means if a panel’s NRC is 0.8, it can be said that it will absorb 80 per cent of noise. This “couldn’t be further from the truth”, according to Castelli. “If I have a drum in a room and I’m beat ing the drum, there’s no way that a material that may be, for argument’s sake, 25 mm thick with an absorption coefficient of 0.8, will work — simply because its figure at the low frequencies won’t be 0.8. It’ll be lucky to be 0.2 or 0.3.”
Castelli believes that you have to consider the type of noise that you would expect to produce and then try to match that with the actual performance characteristics of the panels. This should then incorporate the desired reverberation times in deciding how many and what type of panels should be used in a particular project.
Acoustic panels are mostly made out of mineral wool, fibreglass and polyester fibres of varying densities. Fibreglass and mineral fibre panels are more traditional, but according to Castelli, are being overtaken in.
He says: “People don’t like itching ... To some degree there is also the outside issue that fibres are fibres and these are glass fibres and mineral wool fibres and people don’t like those because they feel that maybe they will have consequences some time down the track.”
So not only should building professionals be concerned about the level of acoustic absorption their panels have, but the materials they are made from are also an important consideration.
