Hicham Kabbage, Healthcare/Education Sector Developer at Saint-Gobain Gyproc Middle East, in conversation with Fatima de la Cerna of Climate Control Middle East on the importance of reducing noise levels in school environments
Achieving this can be a challenge, particularly in schools, where student conversations, noisy sporting and other activities, movement of chairs and equipment, and noisy corridors and dining areas are just part of the normal everyday activity.
Classroom acoustics have a direct impact on communication between teachers and students, affecting the learning process as well as the physical and psychological health of both. Furthermore, noise increases the heartbeat, raises blood pressure and reduces the amount of oxygen in the blood – affecting the student’s capacity to concentrate and learn.
What are the standards we should be aiming for?
International standards may vary, and some designers/authorities in the region may choose to write their own. However, most consultants, designers and acousticians follow the guidance contained in the UK Building Bulletin 93 (BB93), which determines the specific acoustic standards for different areas within a school building.
How can we reduce noise levels in schools?
I would like to answer this question by discussing the different types of sound.
Firstly, there is airborne sound. This sound is generated by pupils and teaching and non-teaching staff talking and moving around, and by noisy equipment and activities. It is good design practice to separate noisy areas from quiet ones when designing the interior layout. Where potential noise problems exist, for instance where a busy corridor abuts a classroom, sound transfer can be reduced by interposing a high-performance acoustic-separating partition or ceiling and by acoustically sealing all perimeters and openings.
Designers need to use a common rating to allow them to compare and select different systems, based on performance; the most popular terms for sound insulation are Rw and STC. These are both descriptors for ‘laboratory tested’ sound insulation performance.
The performance specification of the separating element should be selected based on the appropriate Rw rating for the space and any regulatory requirements. (I recommend that stakeholders read through the Middle East White Book and associated user guides for details of all systems available).
Secondly, there is impact sound. This is caused by footsteps, falling objects or vibrating equipment. It is transmitted through the hard structure – generally a floor – and affects the space below or elsewhere in the building. The level of impact noise can sometimes be reduced using a good-quality floor covering, although in some situations it is more effective to install a suspended plasterboard ceiling to the lower space.
Thirdly, let’s look at sound absorption. As well as controlling noise transmission from one space to another, it is important to control the level of noise generated within the area itself. In large spaces, such as the school lobby or restaurant, noise is generated by activity and by people talking within the area, and is exacerbated by the sound waves reflecting off hard surfaces and bouncing around the space. Spaces with a predominance of hard reflective surfaces, such as ceramic tiles, marble or masonry partitions are more likely to suffer high levels of reflected sound, which will impact the speech intelligibility in classrooms. Therefore, students will hear half of what the teachers say, as recent studies on this subject seem to suggest. The best example would be students, who sit at the back of the classrooms or auditoria – they complain of hearing echoes.
It is particularly important to control reflected sound in classrooms, as this can affect the ability of the students to concentrate or to hear what the teacher is saying, and vice versa. Poor attention to sound performance in classrooms has been proven to affect the educational attainments of students.
The simple answer can be to add special suspended sound absorbent acoustic ceilings or wall panels. A qualified acoustician will be able to advise on the type and area of sound absorption required.
A similar effect can be achieved using a flat or monolithic ceiling design, incorporating boards that are fully perforated, with a special acoustic tissue to the back. Separately hung independent panels, or even special retrofit wall panels, can also be uniquely styled to give high levels of acoustic absorption performance.
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