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A REPORT

ON

THE ACOUSTIC ANALYSIS OF THE SCHOOL OF POST GRADUATE

STUDIES

WRITTEN BY

ADEGBOYEGA ADAMS

ARC/10/1076

SOETAN OLUWALEKE

ARC/09/7430

SUBMITTED TO

THE DEPARTMENT OF ARCHITECTURE,

SCHOOL OF ENVIRONMENTAL TECHNOLOGY,

IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE

AWARD OF BACHELOR OF TECHNOLOGY

DEGREE (B.Tech) IN ARCHITECTURE

JULY, 2014

ABSTRACT

This report records the acoustic analyses of the school of post graduate studies. The

report analyses the basic finishing materials applied to the floor, wall and ceiling in relation

to their acoustic properties. This report identifies the major noise sources and also measures

the noise levels of the internal and external noise sources in relation to the building (school of

post graduate studies). The term paper analyses the basic finishing materials of the building

components (walls, floors and ceilings) in relation to their acoustic characteristics. The

materials used for the construction of these building components were analysed in respect to

their acoustic properties; such as how they absorb and reflect sound. Basic noise sources were

identified and detailed with the aid of photographs, figures and tables. Methods of

ameliorating noise levels in the building were carefully highlighted. All data used in the

preparation of this report were gotten through reconnaissance survey and field work except

where cited otherwise.

INTRODUCTION

The school of post graduate studies is located at the Obanla campus of the Federal University

of technology Akure. The building is the administrative unit of the school of post graduate

studies. The building consists basically of office spaces, a business centre and conveniences.

The building is well landscaped with grasses and well paved walkways.

ANALYSES OF THE FINISHING MATERIALS APPLIED TO THE BUILDING

COMPONENTS

The finishing materials analysed are those applied to the floors, walls and ceiling.

FLOORS

There are two different types of finishing materials applied on the floors of the

building. These two materials do have distinct acoustic characteristics. The office interiors

were finished with thick carpets. These carpets have very good acoustic properties. The

readily and easily absorb sound. They are quite useful in reducing reverberation of sound and

echoes. Since they (carpets) absorb sound effectively, they can help reduce noise levels in

buildings. This is because noise is a sound.

Fig 1.0: Showing floor finishing with thick carpet

Source: Author’s Archive (2014)

Fig 2.0: Showing floor finishing with terrazzo


The lobbies in the building were finished with terrazzo. Terrazzo is a poor sound absorber.

The use will enhance reverberation of sound because terrazzo is a hard and solid finishing

material. Materials of this nature always reflect sound.

Plate 1.0: Showing carpet Plate 2.0: Showing terrazzo floor finish

Source: Author’s Archive (2014) Source: Author’s Archive (2014)

WALLS

The wall of the building is masonry finished with emulsion paint. The wall of the

building has very poor acoustic characteristics. The walls of the building will readily and

easily reflect all sounds directed towards it. This will expose the building to reverberation and

echoes. It will also increase the background noise experienced in the building due to the

reflection of sound from the walls.

Plate 3.0: Showing a painted wall Fig 3.0: Showing reflection of sound


CEILING

The ceiling tile is made of asbestos. Asbestos ceiling tiles have fair acoustic

properties. They do not reflect much sound. The ceiling tiles (Asbestos ceiling tiles) can help

reduce noise levels to a moderate scale. The size of the ceiling tile is 1200mm x 1200mm

Plate 4.0: Showing ceiling tiles Plate 5.0: Showing ceiling tiles

Source: Author’s Archive (2014) Source Author’s Archive (2014)

SOURCES OF NOISE TO THE BUILDING

Noise generated within and around the building can be subdivided into Internal and External

sources.

EXTERNAL SOURCES

The major external sources of noise to the building were

1. Generator

2. Vehicle

3. Human conversation

4. Air-Condition

INTERNAL SOURCES

The major external sources of noise to the building were

1. Office equipment

2. Human conversation

3. Air-condition

4. Fan

Fig 4.0: Showing Site Plan

Source: Author’s Archive

In figure 4.0, the major external noise sources are noise from vehicles, noise from generator,

noise from people walking and talking, noise from Air-Condition system.

.

Fig 5.0: Showing Floor Plan


Fig 6.0: Showing Ceiling Plan


Plate 6.0: Showing Approach View


Plate 7.0: Showing Left Elevation Plate 8.0: Showing Rear Elevation


ANALYSES OF EXTERNAL NOISE SOURCES

External noise sources are noise sources located outside the building. In the building

surveyed, the common external noise sources were noise from vehicles; noise from generator,

noise from air-conditions and noise from people conversing around the building.

1. Noise from vehicles: the noise produced from engines and exhausts of vehicles

moving around the building can be termed vehicle noise. The noise is often

annoying and can make people uncomfortable. Noises of very high decibel are

also produced from the horns of these vehicles.

2. Noise from air- condition: The noise generated from the air-condition system is

termed air-condition noise. When the Air-Condition system is old and faulty it

produces a high level noise that can create discomfort.

3. Noise from Generator: Noises produced from generators are often termed

generator noise. In the building surveyed, the generator set was placed few metres

away from the building. The closeness of the generator to the building produces a

very high level of discomfort to the users of the building.

4. Noise from Human conversation: Conversation between people outside the

building can constitute external noise. It was quite evident from the survey that

people talking at the top of their voice produces a high level noise that can cause

disturbance and make users of the building uncomfortable.

Plate 8.0: Showing a Generator Plate 9.0: Showing Air-Condition


ANALYSES OF INTERNAL NOISE SOURCES

1. When a noise source is located inside a building, the noise generated from the

source is termed “INTERNAL NOISE”. Office equipment (computers, printers,

scanners and photocopiers) people talking or conversing inside the building the

Air-condition system and electronic devices (television, radio etc) were the major

sources of internal noise in the building surveyed. Air-Condition noise: The

noise generated from the air-condition system is termed air-condition noise. When

the Air-Condition system is old and faulty it produces a high level noise that can

create discomfort.

2. Human noise: Conversation between people inside the building can constitute

external noise. It was quite evident from the survey that people talking at the top

of their voice produces a high level noise that can cause disturbance and make

users of the building uncomfortable. People whispering quietly can also generate a

faint amount of noise

3. Noise from office equipment: These are noises generated from computers,

printers and scanners. Although they do not produce high level noise but when

they become old and faulty they can produce high level noise.

4. Fan noise: These are noises generated from the rotational movements of the fan

blade. At top speed the noise becomes quite evident and disturbing compared to

when the fan is at low speed.

Plate 10.0: Showing an Office Interior Plate 11.0: Showing Business Centre


Plate 12.0: Showing Court-yard Plate 13.0: Showing an Office Interior


Plate 14.0: Showing a Ceiling Fan Plate 15.0: Showing an Air-Condition


ASSESSMENTS OF THE BUILDING ACOUSTIC CHARACTERISTICS

The acoustic characteristics of the building was assessed under the following

1. Reverberation: Reverberation is the persistence of sound after its source has stopped.

The acoustic characteristics of the building were good in relation to reverberation.

The wall finishes have very poor acoustic properties and would ordinarily enhance

reverberation of sound but the floor finishing material and the ceiling tiles are good

absorbers of sound. The furniture used in the building can easily absorb sound thereby

further reducing the noise level and also reducing the effect of reverberation. The

building experiences very low reverberation effect.

Plate 14.0: showing furniture Plate 15.0: Showing furniture


2. Background noise: The noise produced from cars outside the building section, noise

from users of the space and noise from the air-condition unit makes up the

background noise. In the building explored, the background noise was quite high.

These is due to the noise from radio set, movement of people around the building and

the presence of air-condition unit. Frequent whispering from users of the space also

contributed to the background noise.

3. Echoes: Due to the low effect of reverberation, there was no echo noticed within the

building, immediately a sound source becomes inaudible, there were no other audible

sound perceived.

MEASUREMENT OF INTERNAL NOISE LEVELS

S/N Noise Source Sound in dB

1 Quiet office with no one inside 30dB

2 Normal Conversation 50-55dB

3 Air-Condition 45-55dB

4 Office/ Office equipment 50dB

5 Quiet Conversation 30-35dB

6 Ceiling Fan 60-65dB

7 Business Centre 70-80dB

8 Reception 60-65dB

9 Noise from Radios in some offices 65-70dB

Table 1.0: Showing Measurement of Internal Noise Level


MEASUREMENT OF EXTERNAL NOISE LEVELS

S/N Noise source Sound in dB

1 Vehicle noise 75-80dB

2 Human conversation 60dB

3 Air – condition noise 50dB

4 Generator noise 80dB

5 Rustle of leaves 15dB

Table 2.0: Showing Measurement of External Noise Level


METHODS OF AMELIORATING NOISE LEVELS IN THE BUILDING

1. All faulty equipments used in the office should be replaced with new ones. This is

because old and faulty equipment tends to generate more noise compared to new

equipment.

2. All new equipment to be purchased should meet the required noise level standard as

stipulated by appropriate authorities

3. Ceiling tiles should be replaced with soft perforated tiles

4. Fan noise can be reduced by reducing the fan speed to a moderate level. Although this

might reduce the effect of the fan.

5. Areas generating much noise in building should be grouped together.

6. The generator should be placed farther from the building. The generator should be

placed on a platform that would reduce vibrating effect.

7. The generator should be enclosed.

8. The internal painted walls should be covered with thick curtains. This will reduce the

reflection of sound from walls thereby reducing reverberation.

9. Air –condition units should be cleaned and serviced at regular intervals. This is

because dust can cause friction and this may cause noise when in use

10. Shrubs should be planted to serve as a barrier against direct vehicular noise

CONCLUSION

The space surveyed and the entire building has a fair acoustic characteristics.

Architects should acquaint their clients with sustainable building materials with good

acoustic characteristics. Where necessary, architects should specify quality materials or

equipments that have good acoustic characteristics. Architects should indicate from the site

plan the exact placing of equipments so that equipment with the same noise level should be

placed together at a reasonable distance from the building. Architects should also specify

quality finishing materials with good acoustics characteristics. Architects should also advise

the client to “BUY QUIET” when purchasing new office equipments

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