7 minute read
A class act in acoustic design
By Heather Barker Vermeer
Industry Reporter Clear, balanced acoustics help facilitate clear communication and eff ective learning.
Acoustics go beyond noise. Acoustic design considers how sound travels around a room: whether in the classroom, library, gymnasium or music hall, sound quality makes all the diff erence as poor acoustics aff ects learners’ speech comprehension, concentration, behaviour, academic att ainment, and wellbeing. Several studies have shown that poor classroom acoustics negatively aff ect the teaching and learning process, especially in earlier grades. For instance, research by Astolfi et al published in a 2019 issue of Frontiers in Psychology found that “long reverberation times, which are associated with poor classroom acoustics as they generate higher noise levels and degraded speech intelligibility, bring pupils to a reduced perception of having fun and being happy with themselves”. Focused on the experiences of six- and seven-year-old learners, the study also linked “bad classroom acoustics” to “increased perception of noise intensity and disturbance, particularly in the case of traffi c noise and noise from adjacent school environments”.
Image courtesy of Autex Acoustics
The two major culprits behind bad classroom acoustics
Background noise can come from external sources, such as cars, lawnmowers, sirens, and thunder, as well as from within the building such as students shouting in a hallway, humming computer equipment, air conditioning units, and the ruckus of infl exible furniture being moved around. Background noise in New Zealand classrooms generally ranges between 28 – 60 dB, according to The Oticon Foundation. The Ministry of Education currently requires that ambient noise levels in a classroom, or fl exible learning space, should not exceed 35 – 45 dB.
Meanwhile, reverberation sounds can bounce off desks or walls and if several sounds are doing this at once, they can be hard to decipher. However, there are several steps schools can take to reduce background noise and reverberation in any space used for learning. Here are some simple solutions we gathered from the sector: • Add rugs or a carpet to the room.
• Install curtains or blinds in the windows.
• Hang soft materials, such as felt or corkboard on the walls.
• Place tables at angles around the room instead of in rows.
• Turn off any noise-creating equipment when not in use.
• Replace noisy light fi xtures and fi tt ings.
• Add dividing screens.
• Place soft tips on the bott om of chairs and tables to reduce the screech eff ect.
For a more permanent solution, adaptations to ceilings and fl oors can be made or incorporated into new classroom design.
Developments in research at AUT, for example, have discovered intelligent algorithms that can interpret sound waves, categorise sound activity, and calculate the required rotation of classroom louvres so reverberation is optimised in real time.
Industry Viewpoints: Aesthetic Refurbs to Reduce Reverb
Autex Technical Development Manager, Rob Jones told us his simple rule when it comes to acoustics in learning spaces: “For good intelligibility, a reverberant sound fi eld cannot exist.”
“Modern teaching spaces are oft en a series of interconnected spaces and, as such, there is greater volume and less available surface area. Because of this, many acoustic consultants believe we can no longer apply too much absorption in these spaces; instead, as many surfaces as possible should have acoustic treatments applied. “Ceilings must be acoustically absorbent and, ideally, also assist in reducing external environmental noise from interfering with learning. This means solid linings that do not allow noise to fl ow through them are essential. Aft er all, if water can leak through, so can sound. The solution is oft en that solid plasterboard is fi tt ed with acoustically absorbent material to reduce outside noise, and fi ns, baffl es, or clouds are suspended to soak up noise generated inside the space. “For walls, a good rule of thumb is to ensure that at least one
Image supplied by Asona, Installation of Triton 50 Clouds for the Ministry of Education Ngā Iti Kahurangi Programme
opposing surface is acoustically treated, particularly when adjacent to glazed panels or other reflective surfaces.”
In terms of retrofit acoustics, “attention should be paid when choosing to simply remove walls to create an open plan space as they are acoustically troublesome and are different from purpose-designed, connected spaces better able to incorporate higher functioning zoned spaces through non-uniform geometry”. “For new and retrofit projects, specialists can supply examples and case studies with design ideas and working evidence that the products perform as intended.” Neil Ridgway, from Asona, outlined what he believes are three best moves a school can make when it comes to classroom acoustics. He said:
“First, schools should consult the Ministry of Education’s Designing Quality Learning Spaces (DQLS) – Acoustics documentation and seek sound advice.
“Second, to manage the reverberation time across all frequencies they should use a 40-50mm thick acoustic ceiling panel, maximise coverage and don’t rely on thin carpet and wall coverings which are not sufficient by themselves. “Third, when investing in acoustic upgrades of classrooms they should consider buying NZ made panels with high local content, low carbon footprint and environmental accreditation.”
Space requirements are pivotal when it comes to retrofitting school acoustics: “Having a balanced reverberation time response from low to high frequencies is the goal of the 2020 DQLS – Acoustics. Under the DQLS - Acoustics, all schools under MoE are required to meet standards whether new build or retrofitting. The general recommendation is to engage an Acoustic Engineer.” Moreover, “as we move from remote learning back into learning spaces, we need to be very mindful of moving from a quiet home environment to a full class of 30+ voices. The transition back to the office or classroom after working from home has been significant for all of us and we must consider calming and balanced environments, so acoustic balance is fundamental.”
https://www.education.govt.nz/
DQLS Compliant Systems
www.asona.co.nz
Autex Acoustics is carbon
neutral in everything they do
Autex Acoustics is the fi rst company in the interior acoustics industry to have reduced and balanced all carbon emissions from business operations and products to zero.
In the latest step in their sustainability journey, Autex Acoustics have achieved global carbon neutrality to contribute to the international eff ort in addressing climate change. Through smart design, effi cient manufacturing, and verifi ed off sets, their global operations and acoustic products are all now carbon neutral.
As a business they are committ ed to the responsible management and manufacture of their products, from the sourcing of raw materials, all the way through to the packaging of fi nished products, to ensure the long-term sustainability of the planet for future generations. Their ethical, social, and environmental priority is to be carbon neutral in everything they do. Whilst the embodied carbon of their products is naturally low, they still do have a carbon impact. Through their Carbon Neutral Initiative, Autex Acoustics have mitigated their carbon impact by off sett ing the equivalent emissions using certifi ed carbon credits, making their products entirely carbon neutral. These carbon credits are generated from projects focused on renewable energy, fuel switching, and reforestation around the world.
To take action on their commitment to fi ghting climate change, they actively monitor their carbon emissions and are committ ed to being a netzero carbon organisation.
In 2017 they began carbon accounting for their core manufacturing facility in New Zealand, however, as their operational footprint is global they decided to extend the scope of their carbon accounting eff orts to all global operations in 2019. Now that they have baseline data on their global carbon footprint, they are working across the business to establish carbon reduction plans to help further reduce their carbon emissions in the future.
Alongside monitoring their emissions, all their products are now carbon neutral. To achieve this, they assess the carbon emissions generated by their products’ supply, manufacture, and delivery and off set them by purchasing certifi ed carbon credits.
This is considered as an investment in the present and future generations and simply a cost of doing business. It also encourages best practices and sets the bar high as a product supplier in the building industry. Using carbon data calculated by independent experts, they invest in third-party certifi ed carbon credits enerated by the Clean Development Mechanism. Operating at an international level means that they are responsible for protecting a range of communities. This is nothing new to the global organisation as sustainability has been a big part of the Autex Acoustics values for decades now. To date, the move to carbon neutrality is their biggest stride towards reducing the impact that their products and operations have.
Learn more about their sustainability journey: autexacoustics.co/sustainability
