Bad classroom acoustics and high levels of noise
The overhead projector is the noisiest of all the AV equipment. Leena Rantala measures the decibel levels and notes that the noise is above the threshold level of 40 decibels near the projector.
Teachers’ voices have a hard time. Half of teachers suffer from voice disorders that are caused by the noise and bad acoustics in classrooms.
The acoustics and voice ergonomics in the elementary school were researched in a large project that was conducted in 14 schools in the Turku, Tampere and Espoo regions in Finland. The study covered 40 classrooms, 40 teachers and 751 students.
The effects of noise and poor acoustics on the job of a teacher have never before been analysed in such a wide-ranging research.
Leena Rantala, lecturer in logopedics at the University of Tampere, says that a paradigmatic change lies behind the research as the research focus has shifted from the individual to the environment.
”We used to think that the problem was solved if the individual just fixed his or her own voice. Now we think that the environment also plays a role.”
Rantala emphasises that this problem does not only concern teachers. Most people use voice as a tool in their work so everyone shares the same risks.
Voice problems are increasing
Voice problems are on the increase but all the causes are not known. Most of them have to do with the work environment. The noise levels have increased for several reasons.
One reason is the change of teaching methods. The pupils are now encouraged to be active and there are more team work assignments. The OECD Programme for International Student Assessment (PISA) also found that the Finnish classrooms are rather noisy.
”When there is noise, people unconsciously speak more loudly,” says Rantala.
Noise increases the teacher’s stress and work load. This in turn affects the students’ wellbeing and learning outcomes.
Background noise caused by construction techniques
The basic reason for noise and poor acoustics is the construction techniques. Heating, plumbing and air conditioning (HPAC) devices and computers hum and annoy.
33 of the 40 investigated classrooms exceeded the noise standard for HPAC devices. Although computers do not have a standard for noise levels, it was alarming that only two in the data showed readings below 40 decibel which is the limit when a speaker starts to increase her or his voice loudness unconsciously. The noisiest equipment was an overhead projector.
The disadvantage of poor classroom acoustics can be heard as too long or too short reverberation times (echo). 14 classrooms out of 40 were above the recommended level.
Health and voice use are also impaired with indoor air problems which could be avoided with better construction techniques.
Noise attenuation did not work
An acoustic intervention was conducted in ten schools by adding acoustic panels into walls and by diminishing the noise emitted by air conditioning devices. The results were scant. It was possible to lower the noise coming from the AC but the acoustics improved only a little.
“It was a surprise that we were unable to improve the acoustics. The acoustics changed in only one classroom. The other classrooms did not even reach the standard levels,” Rantala says.
Rantala is disappointed that “the workmen did not do what they were supposed to do”. Some of them installed too few acoustic panels and one of them installed more than he should have.
“We should go to the acoustics company and ask if they are actually capable of doing their job,” Rantala says.
A speech therapist does not build a house
There is enough information about noise and acoustics problems but the problem is how the information can be put into practice. A speech therapist and a phoniatrist know what the problems are but they do not have the know-how about construction.
Rantala says that the aim of the research was not to write more scientific publications but to achieve change.
According to Rantala, fixing the problems does not depend on the teachers and the school. What is disheartening is that not even the head teachers of the schools are able to do anything about the construction problems.
The researchers in the field of voice science founded the Finnish association of voice ergonomics last autumn. They want to get acoustics experts to join the association in order to increase the dialogue in the field.
Architects design beautiful but noisy buildings
According to Rantala, the bigger municipalities, such as Helsinki, already know to take acoustics into consideration. In smaller municipalities acoustics does not even cross the builders’ minds.
“This depends on the level of knowledge and the availability of acoustics experts. The construction processes can be quite coincidental.”
Rantala talks about her cousin, a kindergarten teacher, whose daycare centre was able to move into a new building. The level of noise in the new building is so high that her cousin has to wear ear plugs and she comes home from work exhausted.
“Architects design visually beautiful buildings but they do not think about acoustics.”
Many kinds of spaces at the University
According to Leena Rantala, the University of Tampere has acoustically different premises. In the open spaces, such as the downstairs cafeteria in the main building, noise and the clinking of the dishes is quite bad.
Rantala thinks that the large auditoriums, such as the main auditorium, are acoustically easy. The speaker’s voice carries quite well in them. The lecture hall that is used in teaching logopedics, which is downstairs in the A wing of the main building, is problematic. The noise levels go up when the teaching ends in the lecture hall upstairs.
The walls of the offices are paper thin, at least in the main building. Even normal conversation carries from one office to the next which disturbs the people’s work.
Eeva Sala and Leena Rantala: Classroom acoustics and voice ergonomics – from research into action. The Finnish Work Environment Fund, project number 109292. www.tsr.fi.
Text Heikki Laurinolli
Photograph Teemu Launis
Translation Laura Tohka
