A

TECHNICAL REPORT ON

THE ACOUSTIC GUIDELINES FOR PRIMARY AND SECONDARY SCHOOLS

WRITTEN BY

JAYEOLA OLUMIDE A. ARC/09/7390

&

KOLAWOLE KAYODE D. ARC/09/7392

Lecturer in charge

Prof. Ogunsote

Arc. Ganiyu

SUBMITTED TO THE

DEPARTMENT OF ARCHITECTURE

FEDERAL UNIVERSITY OF TECHNOLOGY

AKURE

May, 2014

TABLE OF CONTENTS

1.0 INTRODUCTION

2.0 NOISE; A MENACE IN PRIMARY AND SECONDARY SCHOOL

2.1 SOURCES OF NOISE IN PRIMARY AND SECONDARY SCHOOL

2.1.1 External sources of noises

2.1.2 Internal sources of noise

3.0 NOISE CONTROL

3.1 EXTERNAL NOISE CONTROL

3.1.1 SCREENING

3.1.2 PLANNING

3.1.3 BUILDING DESIGN

3.1.4 INSULATION

3.2 INTERNAL NOISE CONTROL

3.2.1 REDUCTION AT SOURCE

3.2.2 USE OF ABSORBENT SCREEN AND SURFACES

3.2.3 INSULATION

3.2.4 BUILDING DESIGN AND CONSTRUCTION

4.0 CASE STUDY (OYEMEKUN PRIMARY AND SECONDARY SCHOOL, AKURE)

4.1 BRIEF DESCRIPTION

4.2 EXISTING SITUATION

4.2.1 Sources of noise in primary and secondary school4.3 Noise control measure at Oyemekun primary and sec. School4.4 Acoustic Characteristics Of the space

4.4.1 background noise4.4.2 reverberation and echoes

5.0 RECOMMENDATIONS AND CONCLUSION

References

1.0 INTRODUCTION

Acoustics is the interdisciplinary science that deals with the study of all mechanical waves in gases, liquids, and solids including vibration, sound, ultrasound and infrasound. A scientist who works in the field of acoustics is an acoustician while someone working in the field of acoustics technology may be called an acoustical engineer. The application of acoustics is present in almost all aspects of modern society with the most obvious being the audio and noise control industries. (wikipedia)

Architectural acoustics (also known as building acoustics) involves the scientific understanding of how to achieve a good sound within a building. It typically involves the study of speech intelligibility, speech privacy and music quality in the built environment. (wikipedia)

A school is an institution designed for the teaching of students (or "pupils") under the direction of teachers. Most countries have systems of formal education, which is commonly compulsory.

In these systems, students progress through a series of schools. The names for these schools vary by country (discussed in the Regional section below) but generally include primary school for young children and secondary school for teenagers who have completed primary education. (wikipedia). The major aim of this project is to locate and control the sources of noise to a bearing level in the educational system(primary & secondary school). For better understanding of this project, a brief discussion of noise is needed. What is noise?

Noise is any form of unwanted sound which is virtual and subjective in nature. (Harris, 1975) defines noise as a form of sound which is unwanted, annoying, interferes with speech and enough to damage hearing, while Salvato (1982) defines noise as ‘unwanted sound’.

Problems of noise in educational system(primary & secondary school): The findings show that noisy conditions have direct negative effects on learning, particularly language and reading development, as well as causing indirect problems to learners through distracting or annoying them. Laboratory based cognitive psychology experiments have shown that noise affects performance on memory tasks an effect which is at least partly explained by noise interfering with language processing. This suggests that it might be problematic to live in a generally noisy place, and real world research into the effects of chronic noise, experienced by people living near airports or busy roads, confirms this extrapolation. A review of this area concluded that, ‘The evidence for effects of environmental noise on health is strongest for annoyance, sleep and cognitive performance in adults and children.’. (International Journal of Environmental Research and Public Health).

2.0 NOISE; A MENACE IN PRIMARY AND SECONDARY SCHOOL

Noise is a disturbance, especially a random and persistent disturbance, that obscures or reduces

the clarity of a signal.(free dictionary).it is also random, undesirable electrical energy that

enters the communications system via the communicating medium and interferes with the

transmitted message. However, some noise is also produced in the receiver(DAE notes). It has

been shown that excessive noise can have a lasting adverse effect upon on health, lower

efficiency at work and is considered by many people as diminishing to their quality of life. It has

been noted that the perceptivity of different individual to noise differs. It is a fact that it is

possible for people to get used to certain degree noises or to find a minimum background noise

level as being quiet pleasant.

The objective of noise control is the reduction of unwanted sound (noise) to tolerable levels. The

source and what constitutes the unwanted noise should first be determined. The second step is to

refer to standards that give acceptable levels for different situation in building. Also the

psychological and physiological effect of sound on human beings should be known to guide

against the danger of such harmful effects when designing.

2.1 SOURCES OF NOISE IN PRIMARY AND SECONDARY SCHOOL

The major sources of noise in primary and secondary school are generally classified into two; the

external source and the internal source of noise.

2.1.1 External sources of noises

The noise in a classroom is made up of external noise which is transmitted through

the building envelope, plus internally generated noise, so that children in school may

be exposed to noise from a wide variety of sources. External noise is likely to consist

of a range of environmental noise including noise from transportation sources,

industrial noise, plant noise and the noise of people outside the school. An additional

source of noise which is reputed to cause significant disturbance to teaching is the

noise of rain falling on lightweight school roofs

This is also noise generated from sources outside the building. It cannot be insulated

totally but it can be refined to a tolerable levels. These are noise from various forms of

transport, industrial, commercial noise, institutional and noise from adjoining residential

areas. The main ways by which external air borne noise enters classroms is through

windows, doors, gaps in walls and through the roof. In general, even the most inadequate

solid brick or concrete walls have external, good resistance to air bone noises and can

therefore be ignored, except when they constitute partition walls between adjoining

classrooms.

2.1.2 Internal sources of noise

This can either be noise associated with occupants’ activities and operations of the building

services. The major source of internal noise in primary and secondary schools is:

Noise inside a classroom may include noise from teaching equipment (computers,

projectors and so on), noise from building services in the classroom, and noise

transmitted through the walls, floor and ceiling from other parts of the school. According

to the research made by us in primary and secondary school classrooms, found that the

dominant source of noise in a primary and secondary school classrooms is the noise

generated by the pupils themselves as they take part in a range of classroom activities.

3.0 NOISE CONTROL

3.1 EXTERNAL NOISE CONTROL

External noise can be controlled by employing the following method:

Screening Planning Building Design Insulation

3.1.1 SCREENINGScreening is most commonly used in controlling traffic noise, as in the case of a highway passing near the schools. The screen can be made from walls, hedges or other barriers. Landscaping plays an important role in the choice of screens. The most effective position for a screen is nearest the source. 3.1.2 PLANNING

Site planning plays an important role in noise control. The first role is the placement of the building far away from noise sources. This noise sensitive to buildings are placed farthest and they receive additional protection from less sensitive buildings, for example, garages, stores and churches are placed nearer the noise source. In a case where there are strongly directional sources of sounds, noise bands should be avoided in the location of the buildings (lecture note). Trees and landscaping are additional tools that may be employed.

3.1.3 BUILDING DESIGN

From the inception of a building design, an architect should put into consideration the noise that will be generated from the activities of the users of the building. Noise from within classrooms originates from people. Noise can be controlled by zoning spaces with respect to the amount noise generated in the space; Noisy, quiet, and semi quiet zone. This spatial segregation can effectively reduce noise transmission.

Noisy spaces such as football pitch, basketball court, and playing ground should be grouped together. Quiet spaces such as offices, library should be grouped together.

The position and orientation should prevent noise penetration and special elements such as long walls and screen may be used as additional protection.

3.1.4 INSULATION

Another important aspect of room acoustics is insulation from unwanted sound. This is obtained by carefully sealing even the smallest openings that can leak sound, by using massive walls, and by building several unconnected walls separated by dead spaces.The use of sound insulating materials in external walls openings can reduce external noise. Increasing the thickness of walls and reducing the size of openings in them improves their sound insulation. Improving the quality of road surface within the school can also help to reduce traffic noise.

3.2 INTERNAL NOISE CONTROL

Internal noise control can be achieved by the implementation of the following.

Reduction at source

Use of absorbent screen and surface

Insulation

Building design and construction

3.2.1 REDUCTION AT SOURCE

This is usually applicable when the sources of noise are from the pupils. The best way to

reduce the noise is for the pupils to be quiet.

3.2.2 USE OF ABSORBENT SCREEN AND SURFACES

The finishes or material use for the surface of some classrooms can act as noise screen in

the building. For instance soft wood paneling will absorb noise or sound more than

concrete walls. There are four types of absorbent materials

Porous absorbents (Best for high frequencies)

Membrane absorbents (Best for low frequencies)

Resonant absorbers (Resonator)

Perforated panel absorbent

3.2.3 INSULATION

The reduction of transmission of sound could be effectively achieved by sound

insulation. Noisy equipments such as generator may thus be placed in well insulated

enclosure. Air borne sound can be reduced by airtight and noise insulating constructions.

Structure-borne sound can be reduced by creating sound gap, separating structures

(walls).

3.2.4 BUILDING DESIGN AND CONSTRUCTION

The major sources of noise within a classroom originates from the pupils, from teaching

equipment (computers, projectors and so on), and noise transmitted through the walls, floor and

ceiling from other parts of the school. The normal practice is to group noisy zones together as

well as quiet zones. This spatial segregation can effectively reduce noise transmission especially

when combined with insulation.

4.0 CASE STUDY ONE (OYEMUKUN PRIMARY AND SECONDARY SCHOOL)

4.1 BRIEF DESCRIPTION

Oyemekun Grammar School was established in January 1953 located on Oyemekun Road Akure, the capital of Ondo- State of Nigeria. The school acccommodates hundreds of students and pupils but in an uncondusive environment. Divided into different levels or standard for senior students (SSS1-SSS3), junior students (JSS!-JSS3) and primary school pupils. The school still seems like the most popular within the Akure metropolis. With only one known major entrance, the school roughly accommodates about 23 buildings; both developed and those of delapidated structures. A major road connects the major entrance.Descriptions of some elements in the secondary school classroom visited is analysed in the table below;

Parameter DescriptionWalls and doors The walls are made of cement plaster of smooth cast finish with

surfaces rendered in emulsion paints, where wallsare of hollow block ; doors have been vandalised.

Floors Made of cement and sand screedCeiling Made of asbestos sheets of 1200x1200mm sizeShape RectangleInternal noise level Ranges between 63dB-74dBExternal noise level Ranges between 62dB-72dBLength of the space 7.8mWidth of the space 7.5mNumber of students in the space

28

Table I: showing the description of some elements in the selected space.

4.2 EXISTING SITUATION

4.2.1 site plan of Oyemekun primary and secondary school showing sources of noise.

Figure2; showing the floor and ceiling plan of a selected space in the building

PICTURE GALLAERY

picture showing the exterior elevation, the interior floor finishing and ceiling material.

Figure 1; showing site plan and sources of noise

SOURCES OF NOISE AT OYEMEKUN GRAMMAR SCHOOL

field source; showing the basketball court and football pitch very near to the classrooms

Field source; showing the parking areas and untarred road located opposite the classrooms

Description of some elements in the primary school classroom visited is analysed in the table below;

Parameter Description

Pictures showing the interior elevation, the materials and finishes

Walls and doors The walls are made of cement plaster of smooth cast finish with surfaces rendered in emulsion paints, where wallsare of hollow block ; doors are made of strong metal

Floors Made of thermoplastic tiles of 250x250x3mm sizeCeiling Made of asbestos sheets of 1200x1200mm size painted whiteShape RectangleInternal noise level Ranges between 58dB-80dBExternal noise level Ranges between 57dB-64dBLength of the space 7.8mWidth of the space 6mNumber of students in the space

30

TableII: showing the description of some elements in the selected space

Figure3; showing the floor and ceiling plans of the primary school classrom

PICTURE GALLERY

Field source; showing the floor, wall and ceiling finishes and the furniture materials

SOURCES OF NOISE AT OYEMEKUN PRIMARY SCHOOL, AKURE.

Field source; showing the playing ground and access road across the school

4.3 NOISE CONTROL MEASURES TO BE TAKEN IN OYEMEKUN PRIMARY & SECONDARY SCHOOL

(1). Trees are often used as buffer zones to muffle the effect of noise from the sources of noise (basketball court, football pitch and pupils’ playing ground) and the adjoining classrooms.

(2). Adequate setbacks ought to be observed while planning the classroms. A buffer zone could also exist.

(3). Site planning accounts for noise reduction measure taken against traffic noise filtering into the classrooms.

4.4 ACOUSTIC CHARACTERISTICS OF THE CLASSROOM AT OYEMEKUN GRAMMER SCHOOL

4.4.1 The acoustical condition of a room is influenced by reverberation, background noise, echoes, and the size and shape of the space. Reverberation.

Reverberation is the persistence of sound after it has stopped. Consequence of reflections

e.g. EchoesFigure 4; reverberation time Reverberation time is the time required for the sound level in the room to decay 60 dB, or in other words, it is the time needed for a loud sound to be inaudible after turning off the sound source. The reverberation time is directly proportional to the volume of the room and is given by: t = 0.05V / a Where: t = reverberation time of room (s) V = volume of the room A = total room absorptionThe total absorption in a room is found by adding the absorption of the surfaces, the seats and the students. The ideal reverberation time for speech is about 1 second and the maximum acceptable time is about 2 seconds.Background Noise.This is the normal prevailing ambient noise from many sources including street traffic and outdoor noises in general. Other sources include air conditioning equipment, structure-borne noise from mechanical equipment, noise from adjoining rooms and noise from the audience itself. Such background noise may reduce speech intelligibility. When

such noise is present, the loudness of the original sound must be increased to overcome the effects of interference. The background noise may also be reduced at source. These sources, both internal and external should be studied and proper remedial measures taken.

5.0 RECOMMENDATIONS AND CONCLUSION

The problems of noise in primary and secondary school have over the years been a threat to the quality of life of its occupants. However noise cannot be totally taken away from our environment, but it can be reduced to a bearable level for housing condition to satisfy its primary goal as a total environment where human being lives, which consequently should be devoid of unpleasant situation and most especially when noise is involved. The active participations of government, architects and other professionals in the building industry can help to reduce this issue. Sound is characterized by many uniqueness as a wave especially within an enclosed space. The study of these characteristics is of great importance in architecture. This is more pronounced in the design of large enclosed spaces designed for speech, music or quiet. Having carefully studied the acoustics guidelines within an enclosed space, it can be said that the importance of the adequate knowledge of this subject cannot be over-emphasized. It is imperative that the understanding of the acoustics guidelines and related issues within a confinement is a foundation in achieving acoustically sound spaces by architects and this must be taken into consideration right from the conception stage of a design to the very finishing of the construction. Nevertheless, acoustic should be considered as a positive factor in design, equal with other factors and not as a matter of ‘treatment’ when the design is finished.

REFERENCES

Ogunsote O. O. (2014): Lecture notes on acoustics.

Microsoft Encyclopedia Encarta Acoustics, Sound, Ear and Noise.

Acoustics.com (2005): Project Remedies-Controlling Noise between Spaces.

Wikipedia

J. Building Acoustics 10(2), 97-106, 2003 The effects of noise on children at school: a review

http//www.sdngnet.com/File/Lectures/FUTA-ARC-507