Best practice: classroom acoustics – a sound education

Sound quality has a very real impact on teaching and learning standards. Connect explains how health and safety professionals can help to improve things.

Headlines

• according to the Association of Teachers and Lecturers, those who work in education are eight times more likely to suffer voice problems than any other worker
• reflections of sound off walls can increase noise and reduce the quality of sound, making it both difficult to hear and potentially damaging to the ears
• Building Bulletin 93 has applied to the building of new school classrooms since 2003, providing guidance and a regulatory framework for the acoustic design of schools
• teachers should log their noise exposure times for a typical week and correlate that with noise dose, with the help of a safety advisor

As most of us know, too much noise can cause long-term hearing damage, while poor classroom acoustics can make it difficult for pupils to concentrate or to distinguish speech against background noise. And many teachers are risking long-term damage to their voices as they strain to make themselves heard. In fact, according to the Association of Teachers and Lecturers, workers in this profession are eight times more likely to suffer voice problems than any other worker.

Under the Control of Noise at Work Regulations 2005, the first action level for noise in the workplace is 80 decibels. At this level, employers must assess the risk to workers’ health and provide them with information and training. Hearing protection becomes compulsory at 85 decibels, based on an average figure for daily or weekly exposure. Noise levels in schools and colleges can exceed these levels – in music rooms, for example, or in carpentry and joinery workshops when machinery is being used.

In some cases, noise levels are high enough to make hearing protection compulsory, but in others, it might be worn on a voluntary basis. This, in turn, presents challenges – there are accounts of disposable ear plugs being difficult to fit and muffling sound so that lecturers have to shout to be heard, once more raising those voice problems. To resolve the issues, some colleges have provided ear defenders with intercoms, but these come at considerable cost.

“Acoustics can pose a significant problem if classrooms are not purpose-built,” says David James of the Industrial Noise and Vibration Centre, who runs IOSH professional development courses in noise and vibration at work. “Reflections of sound off walls can increase noise and reduce the quality of sound, making it both difficult to hear and potentially damaging to the ears. Echoing classrooms – where sound reverberates for a long time – can also reduce the clarity of speech, while poor wall insulation, such as folding room dividers or partitions that extend only to the false ceiling, allow in noise from adjacent classrooms. If that’s a loud noise – say from a music lesson – it can have quite a disruptive effect on the lesson, and on pupils’ concentration.”

Building blocks

Many noise and acoustic issues are part of the fabric of school buildings, and regulations are now in place to address these. James explains that Section 1 of Building Bulletin 93 gives the performance targets for compliance with Requirement E4 from Part E of the Building Regulations 2000: “Each room or other space in a school building shall have the acoustic conditions and the insulation against disturbance by noise appropriate to its normal use.”

Building Bulletin 93 has applied to the building of new school classrooms since 2003, providing guidance and a regulatory framework for the acoustic design of schools. But it doesn’t only apply to new buildings. Many of the UK’s schools are much older, and even modern school buildings that predate Building Bulletin 93 were often built using lightweight materials that don’t stop sound getting in from outside.

“All school buildings are now subject to detailed design checks and on-site inspections by building control officers,” explains James, adding that the Control of Noise at Work Regulations are there to protect teachers, while general duties under the Health and Safety at Work Act will safeguard pupils. “If measures are correctly applied according to the regulations, there should be no risk to students’ hearing.”

Assessing the risk

The sheer variety of classrooms in terms of age, dimensions, materials and use can make acoustic assessment seem a daunting task. Not so, says James: “Taking a music classroom as an example, issues such as room size, room acoustics and the spacing of pupils will make similar music sources have a different noise level according to the environment.”

The HSE stresses that the length of exposure to noise (dose) is as important as the decibel level.

“Risk assessments are performed with a combination of hand-held instruments and personal dosimetry,” explains James. “In a music room, you’d assess each instrument or group of instruments and relate level to dose based on typical practice/performance times for students and teachers. However, there’s already published information on indicative noise exposures, so a combination of limited measurements, published values and a log of typical exposure times for staff and students should provide the basis for a risk assessment.”

Noises off

While purpose-built classrooms will involve a significant amount of money, modifications to existing classrooms can be surprisingly straightforward and cost-effective.

“Carpets, drapes, acoustic screens, redesign of speaker layouts and amplifier volumes are some of the measures that schools can take,” says James. “Craft departments could make some of the improvements using standard, low-cost noise control materials.”

Students and teachers can also help themselves. “In the music room, noisy and quiet pieces could be mixed so there isn’t prolonged exposure to high noise levels,” says James. “Musicians’ plugs can be used to reduce noise exposure without cutting out sound, and practice mutes and drummers’ practice pads should be used. Teachers can safeguard themselves by standing offline from directional instruments such as brass, and acoustic screening can be used to separate teachers from students.”

Careful monitoring will also help to identify any issues and resolve them before they cause problems, says James:

“Teachers should log their exposure times for a typical week and correlate that with noise dose, with the help of a safety advisor.”

A sound education

Fittingly, the effective prevention of classroom acoustic problems begins in the classroom. From the MP3 players they listen to now, to the working environments they’ll find themselves in as they get older, noise is a key area for the development of hazard awareness in young people. In fact, teachers of some subjects, including music and design technology, have a responsibility to make noise awareness part of their students’ education.

“Teachers and students should have noise awareness training,” says James. “Teachers should be aware of the risks presented by long-term exposure to high levels of sound and present noise awareness sessions to each new group of students. This advice could include the message that noise-induced hearing loss is caused by excessive exposure to sound from any source, and the hearing mechanism doesn’t differentiate between pleasant sources such as music and less appealing sounds such as industrial machinery producing the same noise level.

“The students should also carry this awareness to out-of-school activities such as performing in bands and the added risks from using personal stereos at high volume.”

Noise is just one of the risks covered by IOSH’s Workplace Hazard Awareness Course (WHAC), an accessible and interactive course designed to help teachers prepare their students for the real world. WHAC supports the delivery of an entry-level qualification from the British Safety Council Awards. WHAC is free to download for teachers or anyone who delivers free or publicly-funded training.

Links

Sound Advice