Effects of shared noise control activities in two primary schools

Abstract

Worldwide research has demonstrated the influence of bad acoustic conditions inside primary schools on pupils' learning and achievements and on teachers' stress. It has been also demonstrated that noise levels during school activities can be over 75 dB(A). Although the lack of sound insulation and sound absorbing units is of main concern for the phenomena, social and environmental context of the school can have also a dominant effect. In this paper are presented the results of a pilot study named "Sshh…school" conducted in two schools located in different places (a strongly urbanized area and a small village). The pilot study had the aim to sensitize all school actors (management, teachers, parents, pupils) to the problem and to find together the possible remedies to control it. Among others the effects of an information and instruction campaign and the introduction of friendly shared and sustainable absorbing materials were investigated.

Full text

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EFFECTS OF SHARED NOISE CONTROL
ACTIVITIES IN TWO PRIMARY SCHOOLS
G. Iannace1 , G. Ciaburro1, L. Maffei1
1Built Environment Control Laboratory Ri.A.S., Second University of Naples, 81031 Aversa, Italy
gino.iannace@unina2.it
Abstract
Worldwide research has demonstrated the influence of bad acoustic conditions inside
primary schools on pupils’ learning and achievements and on teachers’ stress. It has been
also demonstrated that noise levels during school activities can be over 75 dB(A). Although
the lack of sound insulation and sound absorbing units is of main concern for the
phenomena, social and environmental context of the school can have also a dominant effect.
In this paper are presented the results of a pilot study named “Sshh…school” conducted in
two schools located in different places (a strongly urbanized area and a small village). The
pilot study had the aim to sensitize all school actors (management, teachers, parents, pupils)
to the problem and to find together the possible remedies to control it. Among others the
effects of an information and instruction campaign and the introduction of friendly shared
and sustainable absorbing materials were investigated.
Keywords: classroom acoustics, sustainable absorbing materials.
1 Introduction
Several worldwide studies have confirmed that in primary schools A-weighted sound
pressure levels (LAeq) may exceed 75-80 dB(A) [1,2]. This situation has negative effects on
teachers’ performance and pupils’ achievements and, in some cases, health problems
(stress [3], long term hearing damage, vocal disease) can be registered.
Although background noise levels can be influenced by external sources (road traffic, air
flights), it is of main concern the noise generated by the activities of the pupils. Several
factors can influence this situation: absence of sound absorbing materials, overcrowded
classrooms, pedagogic organization and, last but not least, the social and environmental
context in which the school is located. Several attempts to reduce the background noise
levels through passive interventions have been investigated but their impact on the
reduction of the sound pressure levels was found marginal [2].
Invited Paper

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Extended analysis should consider the social and environmental context in which the pupils
live outside the school and how these features can influence pupils’ behavior during school
time. In fact, nowadays, it is customary also at the very young age the use for many
hours/day of portable audio devices (MiniDisc player, CD portable, Walkman, pocket radio,
MP3 player), the hearing of TV at high sound volumes and, for some areas, the exposure to
loud transportation noise.
In this paper are presented the preliminary results of a pilot project, started in year 2009 at
the Second University of Napoli and named “Sshh…school”. The project, combining several
activities, intends to promote the full involvement of school managements, teachers, pupils
and families in solving the problem and to reach, at least in a long term period, good acoustic
conditions inside classrooms.
In the early stage the project has considered the following actions: a) a training course
dedicated to teachers on acoustics, noise risk, correct use of the voice; b) a friendly and
young people oriented information campaign on noise with posters and specific meetings; c)
the shared choice of a new classroom look with low cost furniture but with high sound
absorbing properties.
The actions have been tested in terms of effects on the overall noise levels during the school
time, on the reverberation time and the speech intelligibility in classrooms and on the pupils’
achievement under a dictation test.
2 Methodology
2.1 Study schools
For the first application of the project “Sshh…school” two primary schools in South Italy were
selected. The first school is located in a small rural village on hills (San Leucio del Sannio –
Benevento). The village has a population density rather small (328 ab./km²) compared to
regional values and the soundscape is very quite (environmental sound levels do not exceed
50-60 dB(A) in the main square of the village). Most of the pupils live in country houses
surrounded by natural sounds. The second school is, instead, located in a suburban area
(Frignano- Caserta) with high population density and an urban soundscape influenced by
traffic (surrounding highways and railways) and intensive commercial activities (Fig.1). The
average environmental sound level is over 70 dB(A).
San Leucio del Sannio (Benevento) Frignano (Caserta)
Figure 1 –Geographical view of the location of the two schools.

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The architectural features of the two primary schools are quite similar. The buildings are
dated early ‘70s and they respect the building systems of that time. The classrooms have a
rectangular plant (Figure 2) with floor in granite tiles, walls and ceiling with smooth plaster.
The furnishings is rather poor and include desks for children in aluminum and laminated
wood, chairs, a desk for the teacher, a blackboard.
In Table 1 are reported the main information of the classrooms used for the preliminary
application of the project.
San Leucio del Sannio (Benevento) Frignano (Caserta)
Figure 2 – Classrooms of the primary schools.
Table 1 – Classrooms information
Pupils
N. Pupils’
age Classroom
Length (m) Classroom
width (m) Classroom
height (m) Volume
(m3)
San Leucio 25 9 5.15 6.20 3.45 110
Frignano 18 9 5.80 6.40 3.15 117
The two primary schools were also chosen for the enthusiasm expressed by pupils and
teachers towards the project. Collaboration is considered of primary concern for the success
of the initiative.
2.2 Training and information
With the authorization of the school management a training course of two days was
organized for the school teachers. After a general introduction on acoustics, noise risks and
noise control techniques, the course was concentrated on classroom acoustics with the
presentation of results of worldwide studies and on techniques to optimize the voice signal.
The course was followed by a open discussion with teachers about pupils’ behavior during
school time and about the social context of the school (eg. what pupils do after school time?).
An information week for the pupils was then organized. During this time “acoustics” was
introduced to pupils through sound examples and simple experiments. To get the pupils’
attention, all information were introduced to them by the “decibel family”, a set of cartoon
characters each with its peculiarity. During the week the classroom was decorated with
posters in which each character illustrated topics related to “noise sources”, “how to control

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them”, “which are the correct behaviors”. To the teachers was asked to involve the students
with specific lecturers and researches on “acoustics”.
Figure 3 – The “Noisy Boy” of the Decibel Family
2.3 Absorbing systems
To control the reverberation time, a set of solutions were presented to the school
management and teachers. The final choice was the application on the classroom walls of a
set (12) of economic, simple and hand-made absorbing panels constituted by a sustainable
material “kenaf” mounted on a wooden frame and covered with colored juta. The dimensions
of the panels are 1,40 m x 0,60 m, thickness 50 mm. The coating with the juta was chosen
because of its characteristics of low resistivity (large woof) which do not affect the sound
absorbing properties of the “kenaf” [4]. The pupils selected cartoon images to decorate the
panels and they helped during the drawing and system build-up phases (Fig.4).
Figure 4 –Sound absorbent sustainable panels in kenaf and juta and their absorbing
characteristics.

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3 Measurements and results
3.1 Preliminary measurements
The equivalent sound pressure level inside four classrooms (two for each school) was
monitored for two months before the start up of the project. The monitoring system was
“Oper@” of 01dB Metravib positioned at 0.5 m below the ceiling. All acoustic data was
transferred in “real time” through web to the University laboratory to be stored and analyzed .
Only school management was informed of the monitoring system so teachers and pupils
were not influenced in their activities. The school management supported information on
number of pupils present during monitoring and the type of classroom activities conducted.
The average sound level inside the classrooms of the school in S.Leucio del Sannio was
over 79.0 dB(A) on the two months period, while in the classrooms of the school in Frignano
was 4 dB(A) higher. For the school in Frignano the variance od the sound levels was higher
and in the classrooms for many days the sound levels were over 85 dB(A).
After school time and in the condition of empty room, measurements of acoustic parameters
(reverberation time, EDT, C80, D50, Rasti), in according to EN ISO 3382 [5], were
performed using a spherical omnidirectional sound source, feed by MLS signals. The sound
source was placed near the position normally occupied by the teacher, and the microphone
points were placed in seven different positions, at different heights, to obtain mean values of
the acoustic parameters.
3.2 Post activities measurements
To investigate separately the effects of each action, after two months, in one classroom of
each school was conducted the “training and information” activity while in the other
classrooms were installed the shared absorbing systems. Monitoring of inside sound
pressure level continued for the next month.
Fig.5 reports the time history of the day-LAeq during school time for the periods before and
after the introduction of the absorbing systems. For the classroom in the school of S.Leucio
del Sannio was registered an average decrease of 1.2 dB(A) while for the classroom of the
school of Frignano the decrease was only 0.6 dB(A).
San Leucio del Sannio (Benevento) Frignano (Caserta)
Figure 5 – Time history of the day-LAeq level for each classroom (before and after the
application of 12 sound absorbing panels).

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For the classrooms in which the action was only the “training and information” there was no
significant difference in terms of LAeq between the pre and post action periods.
Acoustic measurements were repeated in the classrooms after the application of the sound
absorbing panels. Fig.6 reports the comparison between the pre-action and post-action
average reverberation time for each classroom in the two schools, while Table 2 reports the
comparison in terms of Rasti.
San Leucio del Sannio (Benevento) Frignano (Caserta)
Figure 6 – Reverberation time, for each classroom, without panels and after the application
of 12 sound absorbing panels.
Table 2 – Values of Rasti.
Rasti Classroom in
San Leucio del Sannio Classroom in
Frignano
without panels 0.66 0.57
12 absorbent panels 0.72 0.72
3.3 Test results
In the classrooms of both schools, before and after the application of the sound absorbing
panels a test to check the speech intelligibility was organized. A dictation of two texts
containing Italian key words (cena/scena; china/Cina; nido/lido; rupi/lupi; buffa/muffa) was
used by the same teacher. The average number of mistakes made by pupils in writing the
correct words was drastically reduced from 25 to 11 in the situation with the absorbing
panels.
4 Conclusions
The first application of the project “Sshh…school” did not show the expected results.
Although the interest of teachers and pupils to the initiative and their full collaboration, the
reduction of the average sound level inside classrooms during school activities was at
maximum 1.2 dB(A) after the classrooms renewal with sound absorbing panels. No
differences were found after the “training and information” action. It was anyway confirmed

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that pupils that live in areas with lower environmental noise tend to be more quite during
school activities (- 4 dB(A)).
Positive effects have been registered, instead, on the speech intelligibility and on the pupils’
achievements under a dictation test once the reverberation time of the classrooms has been
reduced with the introduction of absorbing materials.
A further application of the project requires more monitoring time and also more information
on the pupils’ habits after school time and at home.
This research was co-funded by the Italian Ministry of University and Research- PRIN 2008
References
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environment – before and after acoustic improvements. Proceedings of Internoise 2009,
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[5] EN ISO 3382. Acoustics - Measurement of room acoustic parameters.
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