A STUDY OF THE ACOUSTIC CONDITIONS OF THE

NEW FUTA LIBRARY

FEDERAL UNIVERSITY OF TECHNOLOGY AKURE.

BY

ARC 01 - 9225 IYAMORE GODWIN ROTIMI ARC 01 – 9239 OLALEYE HAKEEM OLATUNDE ARC 01 – 9224 ILESANMI OMOYAJOWO GEORGE

SUBMITTED IN PARTIAL FULFILLMENT OF THE REQUIRMENT FOR THE

AWARD OF BARCHELOR OF TECHNOLOGY IN ARCHITECTURE

TO

THE DEPARTMENT OF ARCHITECTURE SCHOOL OF ENVIRONMENTAL TECHNOLOGY

FEDERAL UNIVERSITY OF TECHNOLOGY, AKURE

APRIL 2007

TABLE OF CONTENTS

Cover page………………………………………………………………………1

Table of Contents…………… ……………………………………………….....2

Abstract………………………………………………………………………..…3

1.0 Introduction………………………………………………………..………....4

2.0 Building Description…………………………………………………………6

2.1 Location……………………………………………………………………....6

2.2 Architectural Design………………………………………………………….6

2.3 Walls……………………………………………………………………….…6

2.4 Ceilings……………………………………………………………………….6

2.5 Floor…………………………………………………………………………..6

2.6 Fenestrations..............................................................................................…....6

3.0 Analysis of Internal and External Sources of Noise…......................................10

3.1 Internal Noise…………………………………………………………….......10

3.2 External Noise…………………………………………………….……….....10

4.0 Assessment of the Acoustic Characteristics of the Circulation Area & whole

Hall………………………………………………………………………….…..…11

4.1 Background Noise……………………………………………………………..11

4.2 The path of sound transmission in the building …………………………......11

4.3 Reverberation and Echoes…………………………………………………..... 11

.5.0 Proposal for Improving the Acoustics of the New Library ………………...12

5.1 Proposal for Reduction of Internal Noise……………………………………..12

5.1.1. Use of Absorbent Screens and Surfaces……………………………….….. 12

5.1.2 Installation of Synthetic tile & Rug on the Floor ……………………..... 12

5.1.3 Overhauling or use of alternative ventilating system ……………….. …. 13

5.1.4 Use of wall cladding with absolvent materials for

the Circulation Area …..……… 13

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5.1.5 Furniture and cabinetry ……………………………………………… 13

5.2 Proposal for Reduction of External Noise………………………………….13

5.2.1 Insulation

5.2.2 The use of Landscaping Elements: such as Trees Shrubs, Hedges,

Soft Paving………………………………………………………………..13.

6.0 Conclusion…………………………………………………………………..14

7.0 References…………………………………………………..……………… 14

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ABSTRACT It Is The Aim Of This Write Up To Describe The New FUTA Library In Terms Of Its

Finishes And Construction Materials. An Analysis Of Noise Sources And The Perceived

Acoustic Properties Of The Reading Room Against Background Noises Generated From Both

The Interior And Exterior Of The Building. Also Include The Proposal For Ways Of Improving

The Acoustic Properties Of The New Library Was Addressed.

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1.0 INTRODUCTION

The analysis of sound in building, weather desired or undesired can be most

expeditiously viewed from the standpoints of source, path, and receiver. The divides the analysis

of acoustical problem into components that can be more easily addressed. Chief sources of noise

in building can be divided into 3 categories:{1} sources associated with the occupant activity and

office equipment, {2} sources associated with the operation of building services, and {3}

sources of environmental sound from outside a building.

Hence, Noise is defined as unwanted or damaging sound, that is, sound which interferes

with what people are trying to do, or sound which has an adverse effect on health or safety. In

order to be able to deal with the problems of noise in the New Library, an analysis of the nature,

Causes and effects of the noise will necessarily have to be carried out, these findings coupled

with the knowledge of basic acoustics (the nature of sound and its physical properties.) will be of

significant importance in solving the noise related problems in the hall hence providing a more

conducive learning environment for the users.

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2.0 BUILDING DESCRIPTION

2.1 Location

The New Library is located at the Obanla closer to the North Gate of the campus; it is

located opposite school of Engineering car park along the Obanla – Obakekere road immediately

after the School of Engineering and Engineering Technology, FUTA.

2.2 Architectural Design

The New Library is designed in a simple geometrical form. It is a two storey building

with central atrium which provided lighting to the circulation area. It functions presently as

Reading Room and Research information centre for undergraduate and other students who have

formal access to facilities.

The internal spaces are divided into various functional units, with well co-coordinated

circulation spaces; its headroom is approximately 5m. The roof is in form of a simple gable

shape. The construction materials used for the various components are as follows:

2.3 Walls

The external approach has vertical element such as wall fin finished with mosaic tiles and the

walls plastered and finished with texcote emulsion paint. As shown in fig. 1.

2.4 Ceilings

The ceiling is finished with 600x600mm suspended acoustic gypsum board which are

good for sound absorption within the interior space. The lighting fitting (fluorescents) and fans

are distributed at interval to achieve uniformly lighting and ventilation. Also the installation of

mechanical means of cooling e.g. Air Conditioning, to achieved adequate thermal comfort.

2.5 Floor

The floor of the main circulation area is finished with both terrazzo and vitrified tiles and

the stair with vitrified tiles which are very sensitive to footfall. While the reading room area were

finished with carpet tiles which provided considerable impact isolation against the sound of

footfalls, heel clicks and drop objects.

2.6 Fenestrations

The doors leading to individual functional units are paneled timber which produced

sound and vibration as results of door slams and the hinged, while the main entrance and

partition spaces are aluminum casement doors. Window openings are made of sliding aluminum

panel windows..

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ARCHITECTURAL DRAWINGS

`

Circulation Area

Aquisition Section

Computer Room

Reference Section

Porter Desk

Entrance PorchConveniences

Circulation Desk

Conveniences

Libarian Office

Catalogue and Periodicals Section

Parking Lot

Stair Hall

Offices

Ground Floor Plan of the FUTA New Library

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Circulation Area

Aquisition Section

Computer Room

Reference Section

Source of Noise From Vehicular Movement

Source of Noise From The Parking Lots

Porter Desk

Entrance PorchConveniences

Circulation Desk

Conveniences

Libarian Office

Catalogue and Periodicals Section

Parking Lot

Stair Hall

Offices

Access Road

Acc

ess R

o ad

SEET Building Parking Lot

FUTA Book Shop

CBN Computer Centre

CCE Building

CCE Admin Building

Analysis of the External Environment of the FUTA New Library.

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PICTURES

Fig.2. the steps finished with vitrified ceramic tiles Fig.1. the right side view showing the vertical elements used for its architectural composition

Fig.3. the floor finished with terrazzo and vitrified ceramic tiles

Fig.4. approach view showing parking space close to the reading area

Fig.5. source of noise from adjoining road to the library

Fig.5. source of noise from impact noise from circulation area

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3.0 ANALYSIS OF INTERNAL AND EXTERNAL SOURCES OF

NOISE.

The sources of noise have been identified and divide under two major titles these are:

3.1 Internal Noise

Most internal noise is generated through human activities which are:

i. Verbal discussions in the classroom.

ii. Occasional dragging of furniture on the floor finished.

iii. Noise from ceiling fans.

iv. Sound and vibration produced by door slams, footfalls, heel clicks and drop objects.

v. Sound signals from GSM phones.

3.2 External Noise

The major constituents of external noise are:

i. Background noise from people talking as they loiter on the walkways around the

building.

ii. Noise from vehicular activities in form of engine noise and hooting of horns.

iii. The parking spaces located in the proximity of the building.

iv. The noise from the adjoining metal workshop has shown building in the figure: 0.1

Sound and vibration produced by occupants includes door slams, footfall, cart roll-bys,

conversation, paging, radios and warning signals. Some of these are almost always undesirable,

while others are most often desirable, or at least needed to be heard. Door slams within the

interior of new library are an everyday occurrence with everyone is familiar especially in a semi-

public place such as library. When a door slams nearby, the loud impact noise is short in duration

and characterized by sound energy over a wide frequency range. A door slam at a more remote

location in a building is much less and sounds different because it is predominately low-

frequency noise. Hence besides being much less loud, the low-frequency sound of a door slam at

a remote location in the building is much less likely to interfere with speech intelligibility. This

can be acceptable in much type of buildings, but in others where extraneous sound is unwanted,

such as in studio, library or rooms dedicated to absolute silence, even distance impact of a door

slam can be unacceptable.

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4.0 ASSESMENT OF THE ACOUSTIC CHARACTERISTICS OF

THE NEW LIBRARY.

The acoustic characteristics of the new library in the light of background noise, path of

transmission, Reverberation and echoes are discussed below.

4.1 Background Noise

The New Library has not been provided with the necessary components that can help in

successfully reducing the external or background noise from proliferating into the interior of the

building hence these noises are still a major problem in the building as they have not been

shielded or completely eliminated. Sound and vibration produced by occupants includes

conversation, door slams, footfalls and warning signals.

4.2 Path of Sound Transmission in the building

The volume of the central void allowed arousing of sounds (airborne sound) from the circulation

area to upper floors. The air in the volume get excited the demising walls between the source

area and the receiving area, causing structureborne in the building. Also the sounds transmitted

from the source area, through small opening in a demising wall into the reading room. Vibration

propagates through the structure to other spaces and reradiates as sound most in these other

spaces. These other spaces are not directly adjacent to the space containing the source, thus

sometimes making the determining the source of structureborne sound difficult.

4.3 Reverberation and Echoes.

The New Library have the ceiling height 5m which determines the reverberation time

of sounds and this time in turns determines speech intelligibility. it is recommended that heights

should be kept between 9ft and 12ft (2.7m -3.6m) in the reading room. The less the reverberant

buildup of speech in the receiving room the ower the speech signal level, and consequently the

less the speech intelligibility based on the amount of sound absorbent materials use.

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5.0 PROPOSAL FOR IMPROVING THE ACOUSTICS OF THE NEW LIBRARY.

The approach to the improvement of the acoustical environment of the new library can

be discussed under the two categories of noise sources i.e. external and internal noise to tolerable

or barest minimum levels.

5.1 PROPOSAL FOR REDUCTION OF INTERNAL NOISE

5.1.1 Use of absorbent Screens and surfaces

Absorbent screens materials and surfaces are efficient in reducing noise generated

through conversation by the users and internally generated noise that would have been

aggravated by multiple reflections from walls. Choice of materials can be made from the

following available types;

Porous absorbents (best for high frequencies)

Membrane absorbents (best for low frequencies)

Resonant absorbers (resonators)

Perforated panel absorbents.

The use of thin plywood or other material in front of a sealed airspace containing

absorbent material could be used as wall cladding in the reading room to avoid structureborne

sound. These could be additional sound absorbing panels in a narrow band along the upper side

of the walls.

Installation of a gypsum board ceiling in one third to one half of the ceiling area is

recommended.

5.1.2 Installation of Rubber synthetic tiles &Rug for the Floor Finishing

It is an established fact that noise from impacts such as shifting furniture and footfalls are

less in carpeted rooms as compared to hard floor finish. A good Carpet over a good pad will

provide sufficient impact isolation against the sound of footfalls, heel clicks and drop objects.

However, where carpet is not feasible, owing to quality and high maintenance costs required and

considering acoustical benefits, special floor-ceiling assemblies can be used. Moreover Synthetic

tiles perform better room acoustic functions than others .but the durability is low and

maintenance cost is high. Most especially the stair case, rugged could place on the vitrified

ceramic tiles used as the floor finished (fig.2). These will reduce noise generated from footfalls.

Also, replacement of wooden Panel Doors with Sound proof door or door with sealing strips is

recommended, especially in the reading room.

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5.1.3 Overhauling or use of alternative ventilating system

The present means of ventilation in the interior of the library is through the use of ceiling

fans, Air conditioning system and natural air which makes it compulsory for windows and doors

to be opened at all times. When the Library hall is in use, a consistence use of air conditioning

units will help in eliminating external noise for reaching the interior spaces. Periodic

maintenance of the fans will also reduce the noise from the rotating parts. And enclosure of

windows for proper distribution of air cooling system will enhance the acoustics of the interior of

the library.

5.1.4 Use of wall cladding with absolvent materials for the Circulation Area.

This helps to limits and reduced the effects of noise transmission from the circulation

area to the reading area. Rugged could be placed at the path of movements in the circulation, as

the vitrified ceramic tiles and terrazzo floor finish in the circulation area generated impact noise

(fig. 3).

5.1.5 Furniture and cabinetry

Use of foam padded and leather finished chairs will go a long way in absorption of some

sound and other furnishings be outfitted with felt sliders to minimize sliding noise. The

installation of closer on all cabinetry. This is to minimize impact vibration that may transmit to

adjacent unit and radiate a sound.

5.2 PROPOSAL FOR REDUCTION OF EXTERNAL NOISE

5.2.1 Insulation

The use of glass of increased thickness can go along way at reducing external noise. The

cladding of the external walls or building façade element at the external wall to reduce

transmission of transportation sound.

5.2.2 The use of Landscaping Elements: such as Trees Shrubs, Hedges, Soft Paving.

These serves as buffer zone and set-back for sound and noise effects on the building. It

also enhances the external acoustic properties of the library. It reduces the impact of noise

generated from the access road to the library and parking lots.(fig.4)

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6.0 CONCLUSION.

Noise control is an issue which should be of prime consideration in any academic

environment; most aspects of learning require a serene environment to aid concentration of the

students.

Apart from the spatial requirements other factors such as construction materials, site

selection, and design and amplification systems for large halls are equally important. An

audiologist and acoustical consultant should be included in both new and remodeled learning

facilities to aid a satisfactory learning environment.

This technical report has revealed some of the ways this type of environment could be

achieved, though the proposals apply specifically to the scenario surrounding the New library,

they are generally accepted principles in achieving an acoustically healthy environment.

7.0 REFERENCES.

Professor Olu Ola Ogunsote.(c)2006/2007 Acoustics and Noise Control Lecture notes

Gary W Seiben, Martin A. Gold, Glenn W Seiben, Michael G. Ermann.

(2000)Language Speech and Hearing Services in the Schools. Vol.31. pp 376-384

Personal group field research & case study.

William J. Cavanaugh and Joseph A. Wilkes.

(c) 1998 Architectural Acoustics: Principles & Practice.

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