Categories: NewsEducation

Classroom acoustics: How to combat noisy learning environments.

<h2 style&equals;"font-weight&colon; 400&semi;"><strong><em>An environment where good communication can take place should be a goal for any classroom&period;<&sol;em><&sol;strong><&sol;h2>&NewLine;<p style&equals;"font-weight&colon; 400&semi;">Excessive noise in schools has been shown to have a detrimental impact on student learning and performance&period; So why is classroom acoustics not yet a <em>prime<&sol;em> consideration in the design of new classroom facilities in Australia&quest; The Building Code of Australia &lpar;BCA&rpar; details only minimum standards for buildings&comma; but no specific recommendations for educational facilities&period;<&sol;p>&NewLine;<p style&equals;"font-weight&colon; 400&semi;">The AS&sol;NZS2107&colon;2000 standard recommends levels for ambient noise and reverberation times in<em> unoccupied<&sol;em> classrooms&comma; however no recommendations are made for <em>occupied <&sol;em>classroom conditions&period;<&sol;p>&NewLine;<p style&equals;"font-weight&colon; 400&semi;">There are no other regulations or standards&comma; Australia wide&comma; that covers all aspects of acoustical qualities in educational facilities&period;<&sol;p>&NewLine;<p style&equals;"font-weight&colon; 400&semi;"><strong>How do you go about controlling sound without guidelines&quest;<&sol;strong><&sol;p>&NewLine;<p style&equals;"font-weight&colon; 400&semi;">You start with two very basic control measures&colon;<&sol;p>&NewLine;<p style&equals;"font-weight&colon; 400&semi;">1&rpar;        <strong>Reduce reverberation <&sol;strong>-use materials with high noise reduction coefficient &lpar;NRC&rpar;&period; <&sol;p>&NewLine;<p style&equals;"font-weight&colon; 400&semi;">Reverberations occur when sound waves strike surfaces in a room&comma; like floors&comma; walls&comma; and ceilings&comma; and are reflected back into the space&period; Reverberation will continue until all the sound waves have been absorbed or have dissipated&period;  Excessive reverberation can cause echoes that interfere with speech intelligibility&period;<&sol;p>&NewLine;<p style&equals;"font-weight&colon; 400&semi;">The most common measure of acoustic reverberation performance is NRC&period; NRC refers to a surface’s ability to reduce noise by absorbing sound&period;  NRC ranges from 0 &lpar;total reflection&rpar; to 1&period;00 &lpar;total absorption&rpar;&period;<&sol;p>&NewLine;<p style&equals;"font-weight&colon; 400&semi;">2&rpar;        <strong>Reduce sound transmission<&sol;strong> – use materials with high Ceiling attenuation class &lpar;CAC&rpar;&period; Open-plan classrooms and classrooms with thin partition walls between instruction areas are problematic as sound transmission between the rooms are not blocked&period;<&sol;p>&NewLine;<p style&equals;"font-weight&colon; 400&semi;">&lpar;CAC indicates the ability of a ceiling to block airborne sound transmission between adjacent rooms&comma; especially when the dividing wall does not connect with the structural ceiling&period; A ceiling panel with a CAC of 40 will reduce transmitted sound by 40 decibels&period; A ceiling panel with a CAC of 35 or higher offers significant sound attenuation properties&period;<&sol;p>&NewLine;<p style&equals;"font-weight&colon; 400&semi;">An acoustical unit with a high CAC &lpar;sound blockage&rpar; may have a low NRC &lpar;sound absorption&rpar;&period;<&sol;p>&NewLine;<p style&equals;"font-weight&colon; 400&semi;"><strong>Other points to consider when selecting an acoustic product<&sol;strong><&sol;p>&NewLine;<p style&equals;"font-weight&colon; 400&semi;">Who carries out the testing for NRC or CAC&quest;<&sol;p>&NewLine;<p style&equals;"font-weight&colon; 400&semi;">Ensure that testing has been carried out by a NATA-accredited aboratory&period;  NATA &lpar;National Association of Testing Authorities&rpar; accreditation reflects a high level of competence&comma; credibility&comma; independence and integrity to the accredited facility&period;<&sol;p>&NewLine;<p style&equals;"font-weight&colon; 400&semi;"><strong>Where is the product from&quest; Can you guarantee the quality of your product&quest;<&sol;strong><&sol;p>&NewLine;<p style&equals;"font-weight&colon; 400&semi;">There have been many reports in the past of building materials being imported to Australia&comma; without meeting Australian standards&period; Beware that you are not buying an inferior product&period;<&sol;p>&NewLine;<p style&equals;"font-weight&colon; 400&semi;">Consider products that are lighter in weight&comma; with improved acoustic performance&period;<&sol;p>&NewLine;<p style&equals;"font-weight&colon; 400&semi;">In the past&comma; heavier products offered greater acoustic properties&period; Advances in technology now provide a myriad of products that are much lighter and have improved acoustic performance&period; It is much more cost effective to install a lighter weight product because more lightweight structural   supports can now be used&period;<&sol;p>&NewLine;<p style&equals;"font-weight&colon; 400&semi;"><strong>Is the product resistant to the local climate&sol;environment&quest; <&sol;strong><&sol;p>&NewLine;<p style&equals;"font-weight&colon; 400&semi;">Past experience has shown that certain products installed in humid conditions may sag as a result of moisture absorption&period; Some might even be prone to mould causing all sorts of hygiene issues&period; Be selective in the materials you choose&period; Ensure that they not only have high acoustic properties&comma; but also applicable to local conditions&period;<&sol;p>&NewLine;<p style&equals;"font-weight&colon; 400&semi;"> <&sol;p>&NewLine;

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