During the winter months, staff and students will be spending more time indoors. Ventilating indoor work areas, whilst at the same time ensuring a comfortable working temperature, will become more and more challenging.
Teaching and learning are acoustically demanding activities, however a great number of classrooms in England and Wales have poor acoustics. Good classroom acoustics enhance teaching and learning, improve student behaviour and reduce the risk of vocal strain for the teacher. But many schools were not built with due regard for the quality of classroom acoustics.
Noise problems in the classroom
The most common acoustical challenges facing classrooms, such as noise transfer between rooms and/or excessive reverberation in rooms, arise for a number of reasons, for example:
- the acoustical properties of 19th and early 20th century schools, which are often unsuited to modern teaching methods
- modern building methods, often reliant on lightweight materials which do not provide adequate sound insulation
- open-plan classroom designs, in which background noise and sound intrusion are difficult to minimise
- multi-purpose areas, such as halls, which must be acoustically suitable for a range of different activities
- specific subject areas in which noise can be a particular problem, such as music and design technology classrooms.
Poor acoustic conditions in the classroom increase teachers’ vocal strain as most teachers find it difficult to make themselves heard above high noise levels.
Classroom building regulations
Prior to 2003, standards governing the acoustical properties of newly-built classrooms were little known and rarely enforced. Since 2003, however, Part E of the Building Regulations (as amended) has been applied to schools in the form of the first section of Building Bulletin 93. Despite this, even some new schools are failing to comply with minimum statutory requirements on acoustics. Glass, for example, is often favoured in modern school design, but it can cause problems as it is an excellent reflector of sound.
Clearly, the best way of achieving good standards of classroom acoustics is for school building designs to follow the statutory requirements of Building Bulletin 93.
This states that:
“In a school with a good acoustic environment, people will experience:
- good sound quality – enabling people to hear clearly, understand and concentrate on whatever activity they are involved in
- minimal disturbance from unwanted noise (such as from activities in adjacent areas, teaching equipment, ventilation fans or road traffic).”
The guidance to the School Premises Regulations 2012 states that classroom conditions should be such that teachers are able to communicate without straining their voices. It also makes it clear that certain types of spaces, such as music rooms, recording studios, open-plan areas and rooms where pupils with hearing impairment are taught might require higher acoustical standards than those applying in normal classroom areas.
SEND and classroom noise
Pupils with special needs may need to be taught in spaces with lower noise levels and shorter reverberation times than in mainstream classrooms.
“Special schools and SEN units in mainstream schools must therefore be designed to a higher acoustical standard. Where pupils with these special needs are taught in mainstream schools, the acoustics of the spaces where they are taught may need to be enhanced to the same standards as those in special units. Provision will usually be required to teach these pupils in smaller groups so that ambient noise from other pupils is lower and the distance between teacher and pupil is minimised.”
Finally, the School Premises Regulations 2012 guidance points out that good management of acoustic conditions in schools is essential. Arrangements to maintain good classroom acoustics must not be allowed to deteriorate through neglect.
How to improve classroom acoustics
Reverberation and sound absorption
There are two ways to reduce the reverberation time of a room: either the sound absorption must be increased or the volume must be decreased. Increasing the sound absorption in a classroom is generally easier to achieve than reductions in volume.
Sound absorption can be improved by the addition of more ‘soft’ materials, such as fabric-faced glass fibre wall panels, carpet, or acoustical ceiling tiles. For many older classrooms with high ceilings, the addition of a suspended ceiling of sound-absorbing tile can significantly improve the acoustics by simultaneously decreasing the volume and increasing absorption.
Having too high a level of sound absorption, however, can create an acoustically 'dead' space resulting in difficulties in communicating.
Long reverberation times favour the build-up of background noise and can impair intelligibility, but short reverberation times can limit the strong reflections needed for those at the back of the classroom to hear clearly.
Noise from adjacent rooms
Noise from adjacent rooms disrupts the learning process, especially during quiet reading times or test-taking. In recent decades, the need to lower construction costs has led to the use of thin, lightweight wall materials that provide little noise reduction. In the 1960s and 1970s, many open-plan classrooms were built with no partitions whatsoever between classrooms. In some schools, such spaces have since been partitioned, but noise reduction between rooms may still be insufficient.
Where the adequacy of a wall dividing two classrooms is in doubt, the following simple test can be applied: set up a television or video monitor in one room and set the sound level so it can be comfortably heard at the back of the classroom. Then go into the neighbouring classroom and listen for sounds from the equipment next door. If sounds are faint or inaudible, the barrier is sufficient. If sounds are fairly loud, and especially if words are intelligible, the partition between the rooms needs to be improved.
The noise reduction of exterior walls is also important since many noisy and potentially disruptive activities go on outside the school. Most schools are built with brick or concrete block exterior walls - which are good sound barriers - but with inadequate windows that permit considerable sound transmission. To provide noise reduction, windows must be well sealed. Double glazing provides better noise reduction than single-paned glass (as well as providing better thermal insulation and decreased energy costs).
Music teachers are at particular risk of sustaining hearing damage as a result of prolonged exposure to very high sound levels in their daily work. Recently, the Health and Safety Executive (HSE) has begun to look more closely at this risk and now suggests that music teachers may need to consider some form of hearing protection in the classroom. The HSE has collaborated with practitioners in the music and entertainment industries to produce detailed guidance on managing the risk of excessive noise to music teachers.
Among other things, the guidance makes the point that many musical instruments create sound that is louder than current noise regulations allow. A cornet, for example, can reach 140 decibels - equivalent to a jet plane taking off. Exposure to such levels of sound can cause immediate and lasting damage to hearing, while lower levels can cause problems to build up cumulatively.
Noise regulations in the workplace
The Control of Noise at Work Regulations 2005 specify a daily or weekly exposure action value (EAV) of 80 decibels. At this level, a risk assessment must be undertaken, and suitable control measures put in place. These might include the wearing of earplugs, standing behind a noise screen and/or advising those at risk not to stand directly in the line of a musical instrument, for example. The regulations also stipulate an upper EAV value of 85 dB, and an absolute limit, the exposure limit value (ELV) of 87 dB. Should this level be exceeded, the employer would be in breach of the regulations.
Controlling excessive noise
Employers must carry out a risk assessment if noise levels are likely to reach or exceed the lower EAV (80dB) and take appropriate action to control such levels. Where sound levels are likely to reach the upper EAV (85dB) the employer must take co-ordinated action through a ‘programme of organisational and technical measures’ in order to reduce noise levels in a systematic and thorough manner.
When looking at ways of controlling workplace noise levels, employers might consider:
- changing working methods
- changing work equipment
- alterations to design of work layout and work stations
- provision of suitable and sufficient information and training for employees
- limiting duration and intensity of exposure to noise.
Employers must not expose workers to levels of noise above the ELV (87dB). If the ELV is exceeded, employers must reduce exposure to below that level and prevent it happening again. Noise levels of 87dB have regularly been recorded in classrooms, and these high noise levels can present significant risks to teachers’ hearing. Prolonged exposures to noise over a number of years can cause hearing loss. Noise can also cause hearing problems such as tinnitus, which is experienced as ringing in the ears, and can be very distressing.
The external environment where teachers work can also have an impact on classroom acoustics and hearing. For instance, the HSE states that working in an environment with intrusive noise, such as a busy street, for most of the working day is likely to indicate a noise problem.
Many schools, particularly in urban areas, are situated near busy towns, roads, railway lines, airports etc. Therefore, the noise of these environments has the potential to reach or exceed the exposure levels. Employers are required to implement measures such as engineering controls, when noise reaches 85dB. Noise from road traffic can be alleviated by noise barriers, as well as landscaped mounds of earth.
Checklist for NEU safety representatives
- Include teacher experience of classroom acoustics as part of health and safety inspections.
- Evaluate which staff might be at particular risk of poor classroom acoustics.
- Ensure the school has completed a full risk assessment of classroom acoustics.
- Ensure that control measures are implemented in full.
- Ask to participate in any discussions about planned refurbishments at school.
For more information, please read 'Acoustics in schools'