Teaching has changed and so have learning approaches of our children. The school is no longer the place for endless teacher monologues and our children are expected to participate in discussions, in group work and in cross discipline projects. Mainstream teaching today is not the same as it was only 15 years ago and the acoustical demands for schools are very often inadequate.
Since 2012, the Danish school system has aimed to include students with special needs in mainstream schools and classrooms. Kids with hearing impairment, ADHD, autism etc. are therefore to attend a typical government provided education structure whenever possible. Unfortunately, the classrooms are rarely ready for inclusion.
Danish Building Regulation
According to the Danish building regulation BR19(08) rooms for traditional teaching require reverberation time (T20) ≤ 0.6 sec. from 125 Hz to 4000 Hz (allowed variation of 20% for 125 Hz) whereas rooms for hearing impaired students or students with other special needs require 0.4 sec. The regulation only concerns new built which causes a challenge since most of the schools in Denmark are built before the regulation got implemented in 2008.
A lot of theoretical work has been done to find out what acoustical descriptors are most beneficial but practical research with smaller children is limited. However, when hearing impaired students are included in the traditional classroom, there is definitely a need to evaluate more than just reverberation time – otherwise potential can be lost due to bad room acoustics.
The study presented at Internoise 2020 investigated if it was possible to see any difference in performance (working memory, listening tests) in a 5th grade class before and after an acoustic refurbishment, and in particular if it was possible to see changes in performance for a hearing impaired girl in the class.
The class in the study was an ordinary fifth-grade class with 20 students. One of the students had a moderate hearing loss. The hearing impaired student had been using hearing aids and a traditional FM-system. However, the system was rarely used because it was perceived as difficult and the sound was noisy. The impairment is classed as medium-level, with higher-pitched sounds causing the biggest problems.
It was decided to keep the original perforated plasterboard ceiling and install the new acoustic ceiling below. This was possible because of the relatively high ceiling height. The ceiling chosen for the classroom was a wall-to-wall absorption class A solution with a 20 mm. glass wool ceiling in a grid system and an extra bass absorber (40 mm.) in a U-shape above the glass wool ceiling (40% coverage). Furthermore, three absorbing wall panels (in total 7,2 m^2) were installed on one wall (they would have a pin board function after installation).
The acoustics results showed that mounting a new ceiling together with wall panels made a great difference on several acoustic parameters.
It was noticed that now the classroom was actually good enough – on paper – to live up to the recommendations for rooms for inclusion. The performance testing of the students revealed that not only was the class average affected by the new acoustic treatment – the hearing impaired student could finally fulfill her potential.
One should keep in mind that there will always be some kind of background noise in a Danish classroom – there will almost never be complete silence since Danish traditional teaching today includes peer-to-peer work, project work, group work and collaborations across the class room.
Also the commutation pairs test and CLPT test showed similar results; the class in average benefitted a lot from the refurbishment and the hearing impaired girl showed to be one of the top-performers of the class! This was a huge contrast to what happened in the classroom before the project was done.
In this project it is clear that if you make a classroom suitable for inclusion everybody will benefit from it – on the other side, if acoustics are inappropriate for teaching – everyone suffers and the vulnerable suffer the most.
Very few of the students performed equally well in the two different acoustic conditions and despite the possible bias on many levels, the statements supported these findings.
One could conclude that all the potential lost in a ‘poor acoustics’ classroom is so much more expensive than paying for the high performing acoustics ceilings and wall panels available. Having said that, one could also conclude that it is impossible for hearing impaired students to get a proper education if room acoustics are not prioritized; it gets too hard, it gets impossible (if you cannot hear anything – education is lost) and the struggle on a personal level becomes unsustainable.
Finally, it can be concluded that evaluating several acoustic descriptors is highly relevant and it is suggested that local standards and regulations set demands for more than RT alone. In short, the study showed:
- Teaching and learning have changed.
- Classrooms should support activities of today.
- Several acoustic descriptors should be part of acoustic standards for schools.
- Optimum acoustic solutions for classrooms include more than just a suspended acoustic ceiling.