ACOUSTIC ANALYSIS OF ADVANCEMENT CENTRE€¦ · acoustic analysis of advancement centre carried out...

Acoustics Analysis Of Advancement Centre Page i

ACOUSTIC ANALYSIS OF ADVANCEMENT

CENTRE

CARRIED OUT

BY

OGA OLUWASEGUN ADEBAYO ARC/10/1139

&

OLADUNNI KABIR AYODEJI ARC/10/1147

COURSE

ENVIROMENTAL CONTROL III (ACOUSTIC AND

NOISE CONTROL)

(ARC 507)

LECTURERS

PROF. O.O OGUNSOTE

ARC S.O GANIYU

SUBMITTED TO

THE DEPARTMENT OF ARCHITECTURE

FEDERAL UNIVERSITY OF TECHNOLOGY, AKURE

ONDO STATE, NIGERIA

IN PARTIAL FULLFILMENT OF THE REQUIREMENT FOR THE AWARD OF A BACHELOR OF TECHNOLOGY (B.TECH) IN ARCHITECTURE

JULY 2014.

Acoustic Analysis Of Advancement Centre Page ii

Pages

TABLE OF CONTENTS ii

LIST OF PLATES iii

LIST OF FIGURES iii

1.0 INTRODUCTION 1

2.0 LITERATURE REVIEW 2

2.1 S0UND 2

2.2 NOISE 3

2.3 ACOUSTICS 3

3.0 ANALYSIS OF THE ADVANCEMENT CENTRE 4

3.1 ARCHITECTURAL DETAIL/ BRIEF DESCRIPTION OF THE BUILDING

3.2 FINISHING MATERIAL ANALYSIS OF THE BUILDING 4

3.3 FLOOR PLAN OF THE BUILDING SHOWING FURNITURE

ARRANGEMENT AND FLOOR FINISHES. 6

3.4 THE CEILING PLAN OF THE BUILDING 7

3.5 SITE PLAN SHOWING THE SOURCE OF NOISE 7

3.6 PICTURE SHOWING DIFFERENT VIEWS OF THE BUILDING 8

3.7 SOURCES OF NOISE TO THE ADVANCEMENT CENTRE 8

3.8 SOURCES OF INDOOR NOISE 8

3.9 SOURCES OF OUTDOOR NOISE 9

3.10 FACTOR AFFECTING THE ACOUSTICS OF THE ADVANCEMENT

CENTRE 10

4.0 ACOUSTICS IMPROVEMENT OF THE BUILDING 11

4.1 PROPOSAL FOR REDUCTION OF INDOOR NOISE 11

Acoustic Analysis Of Advancement Centre Page iii

4.2 PROPOSAL FOR REDUCTION OF OUTDOOR NOISE 11

5.0 RECCOMMENDATION 12

5.1 CONCLUSION 12

REFERENCES 12

LIST OF PLATES

Plate 1: The internal Wall finished with cream emulsion paint. 4

Plate 2: The asbestos ceiling Finish 5

Plate 3: showing window and door type 5

Plate 4: The ceramic tiles floor Finish. 6

Plate 5: showing different facades of the building 8

Plate 6: the ceiling fan used in the building 9

Plate 7: the interior furniture of the building (receptionist/ waiting area) 9

Plate 8: Access road; a source of outdoor noise 10

LIST OF FIGURES

Fig. 1: Floor plan of the building showing furniture arrangement and floor finishes 6

Fig. 2: Ceiling plan of the building. 7

Fig 3: site plan showing the source of noise. 7

Acoustics Analysis Of Advancement Centre Page 1

1.0 INTRODUCTION

Architectural acoustics encompasses room and auditorium acoustics.

Reverberations due to reflections from walls, celieng, and furniture influence room

acoustics. For best acoustic qualities, rooms are designed to produce sufficient reflections

for naturalness, without introducing excessive reverberation at any frequency, without

echoing certain frequencies unnaturally, and without producing undesirable interference

effects or distortion. A failure to adhere to these principles of architectural acoustics leads

to the generation of unwanted or damaging sound that will adversely affect the activities

of intended users when the space is in use.

Sound is a disturbance or wave, which propagates through physical medium such

as air or parts of the building structure in a longitudinal manner from the generating

source to produce sensation of hearing at the receiving end. Sound waves exhibit

reflection, refraction, diffraction and interference. They are characterized by speed of

sound, sound pressure, sound intensity and they obey inverse square law when

propagating from point source (Effion 1997).

Architectural acoustics is primarily aimed at enhancing speech and music clarity

in enclosed spaces. Due to hearing complications arising from both the physiological and

psychological peculiarities of individuals, it is necessary to incorporate environmental

control factors like acoustics in building designs. This is most effective when done in the

early stage of design as opposed to the post-construction phase, which is most prevalent

today.

Aim:

This report is to give an acoustic analysis of the ADVANCEMENT CENTRE

BUILIDNG, located at the Oba-nla staff quarters of the Federal University of Technology

Akure, and to propose qualitative ways in achieving a better acoustics.

Objectives:

To examine the existing acoustics conditions of the building in order to know if

there are adequate provisions for good acoustics.

To analyze the common factors affecting the acoustics of the building both

internal and external sources and proffer solutions

To examine the use of materials in effectively enhancing acoustics behaviour

within the building

Acoustic Analysis Of Advancement Centre Page 2

2.0 LITERATURE REVIEW

2.1 SOUND

Sound is the energy produced by a vibrating object or surface and transmitted as a

wave through an elastic medium. Such a medium may be air (airborne sound) or solids.

Sound is a disturbance or wave, which propagates through physical medium such as air or

parts of the building structure in a longitudinal manner from the generating source to

produce sensation of hearing at the receiving end. Sound waves exhibit reflection,

refraction, diffraction and interference. They are characterized by speed of sound, sound

pressure, sound intensity and they obey inverse square law when propagating from point

source. Effions-Williams, (1997).

Sound is a physical phenomenon that stimulates the sense of hearing. In humans,

hearing takes place whenever vibrations of frequencies from 15 hertz to about 20,000

hertz reach the inner ear. The hertz (Hz) is a unit of frequency equaling one vibration or

cycle per second. Such vibrations reach the inner ear when they are transmitted through

air. The speed of sound varies, but at sea level it travels through cool, dry air at about

1,190 km/h (740 mph). The term sound is sometimes restricted to such airborne

vibrational waves. Sound has various properties amongst which are;

Amplitude: Amplitude is the characteristic of sound waves that we perceive as

volume.

Frequency: We perceive frequency as “higher” or “lower” sounds. The frequency of

a sound is the number of cycles, or oscillations, a sound wave completes in a given time.

Frequency is measured in hertz, or cycles per second.

Pitch: Pitch is the property of sound that we perceive as highness and lowness.

Intensity: Sound intensities are measured in decibels (dB). Sound intensities are

arranged on a logarithmic scale, which means that an increase of 10 dB corresponds to an

increase in intensity by a factor of 10. The distance at which a sound can be heard

depends on its intensity. Intensity is the average rate of flow of energy per unit area

perpendicular to the direction of propagation. Intensity varies inversely as the square of

the distance, provided there is no loss of energy due to viscosity, heat conduction, or

other absorption effects.

Sound Pressure:

McGuiness, et al. (1980) stated sound pressure to be a fluctuating pressure

superimposed on the static atmospheric pressure in the presence of sound.

Since audible sound consists of pressure waves. One of the ways to quantify sound is to

state the amount of pressure variation s relative to atmospheric pressure caused as a result


of sound generated. Pressure level can be evaluated by calculating the logarithmic value

of the ratio of given pressure, P to standard threshold of hearing pressure.

Reverberation Time

Reverberation time is the time for the sound to decay by 60dB (become

effectively inaudible) after the power source is shut off.

Reverberation time = time to drop 60dB below original level (Hunt 1978).

T = 0.3log10V, (3)

where T is the optimum reverberation time in seconds, for speech and V is the

room volume in cubic meters (McGuinness, et al. 1980).

2.2 NOISE

Noise is any form of unwanted sound which is relative 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 is called noise, while Salvato (1982) defines

noise as „unwanted sound‟.

2.3 ACOUSTICS

This is simply defined as the science of sound. This also includes the generation

of sound, the transmission and the effect of sound energy. Architectural acoustics deals

with the provision of good condition for sound in buildings. This involves the design of

building for good speech condition, privacy and freedom from distracting noise.

Acoustics must also provide a good condition for listening. For the provision of good

acoustics condition in a building, acoustical design involves controlling the amount of

sound through absorption or sound insulation, blocking of sound and control of

background noise.

The acoustical condition of a room is influenced by reverberation, background

noise, loudness of the original sound, and the size and shape of the auditorium.

Acoustics of Internal Space

As regards the interior acoustics of a space, the volume of the enclosed area is

developed according to reverberation requirements of the shape. The shape of wall and

ceiling surfaces is developed to give proper distribution of sound and eliminate focusing

or echoes. Other factors to be considered include acoustic quality of finishes on walls,

floors and ceilings, kind of fenestration, furniture surface available etc. (McGuiness, et al.

1980).


3.0 ANALAYSIS OF THE ADVANCEMENT CENTRE BUILDING

3.1 ARCHITECTURAL DETAILS/ BRIEF DESCRIPTION OF THE

BUILDING

The Advancement Center is a 3-bedroom bungalow residential building converted

to office use. The Advancement Centre is saddled with the responsibility of sourcing

funds for the university. The Advancement Centre is located at the Obanla campus of the

Federal University of Technology Akure. The building is bounded by other residential

buildings at its East, Garage and Store to the West, Bounded by trees and vast land mass

to the South, and North respectively, with access road to the North. Cars are being

parked at the side and rear of the building.

The building is a 3-bedroom design bungalow designed to cater for the

accommodation of staffs. It comprises of three bedrooms which has been converted to

offices rooms, a living/ dining room, which is been converted to the reception, a kitchen

and store, as well as conveniences. A square-shaped courtyard is also incorporated into

the design to serve as the entrance patio as well as aid lighting and ventilation.

The building is landscaped with trees and shrubs, and with a simple gabled roof at both

ends.

3.2 FINISHES MATERIALS ANALYSIS OF THE BUILDING

The following are the choice of finishes used in the construction of the various

components of the Advancement Building.

WALLS: 225mm X 225mm X 450mm hollow sandcrete block were used in constructing

the walls, and are finished with emulsion paint on both the Interior and exterior. wet areas

such as toilets, white ceramic glazed tiles were used as wall finish from the floor to the

door height. Gloss paint was then used to complete the remaining surface area.

Plate 1: The internal Wall finished with cream emulsion paint.


CEILINGS: The ceiling is finished with the widely known of 1200mm x 1200mm

asbestos ceiling boards painted with double coat of white emulsion paint and has a flat

shape, which runs through the building to define the building‟s headroom.

Plate 2: The asbestos ceiling Finish

FENESTRATIONS: All internal doors are timber paneled doors, while the main

entrance door as well as the exit door from the kitchen are iron grill doors. Window

openings are made of glass louver blade with wooden frame and nets.

Plate 3: showing window and door type

FLOOR: All floors were finished with ceramic glazed tiles of various sizes varying from

400mm x 400mm to 150mm x 150mm, at different spaces.


Plate 4: The ceramic tiles floor Finish.

3.3 THE PLAN OF THE FLOOR OF THE BUILDING SHOWING FURNITURE,

ARRANGEMENT AND FLOOR FINISHES.

Fig. 1: Floor plan of the building showing furniture arrangement and floor finishes


3.4 CEILING PLAN OF THE BUIILDING.

Fig. 2: Ceiling plan of the building.

3.5 SITE PLAN OF THE BUILDING

Fig 3: site plan showing the source of noise.


3.6 PICTURE SHOWING DIFFERENT VIEWS OF THE BUILDING.

Plate 5: showing different facades of the building

3.7 SOURCES OF NOISE TO THE ADCANCEMENT CENTRE

Noise is usually defined as unwanted or damaging sound. There are several ways with

which noise interferes with the on-going activities in the building. These would be

discussed under two major headings namely:

Indoor noise.

Outdoor noise.

3.8 SOURCES OF INDOOR NOISES

The major source of indoor noise in the building can be traced to the activities of the

users themselves; activities such as verbal interactions with one another, movement from

one place to another with different kind of foot-wears. In addition, electrical appliances

like ceiling fans, air-conditioning and computer systems constitutes a noise problem in

the building. The engines and rotating blades (especially in faulty fans) of ceiling fans

and air conditions and the fans and clanking of the keyboard are some of the ways


through which these electrical appliances generate noise. It is pertinent to note that the

level of noise generated by these appliances is sometimes disturbing or annoying

Plate 6: the ceiling fan used in the building

Plate 7: the interior furniture of the building (receptionist/ waiting area)

Other sources of indoor noise include dragging of furniture on the floor, banging of

doors, etc. These are categorized as impact sounds which at very high levels may cause

hearing damage.

3.9 SOURCES OF OUTDOOR NOISES

Though the Advancement Centre is located at the quiet zone, nonetheless, it ia still prone

to noise from external source. Notable amongst the external source of noise is noise

generated from vehicular and pedestrian movements on the access road, these activities

could be in the form of engine noise, hooting of horns, or loud conversation of passers-by

etc.


Plate 8: Access road; a source of outdoor noise

3.10 FACTORS AFFECTING THE ACOUSTICS OF THE ADVANCEMENT

CENTRE.

The factors that affect acoustics of any building include its size and shape, nature of

materials and finishes, zoning etc. In attempting to analyse the acoustic performance of a

building all these must be considered.

SIZE AND SHAPE

These greatly affect acoustic condition in a room and are the reasons for the definition of

any acoustic condition. The reverberation time increases with the size of a room and

depending on the size, the reverberation time could rise above acceptable standard. In the

Advancement Centre, the rectangular shape and not too large a size of the spaces in the

building enhances good acoustic characteristic

.

FINISHES

The finishes used in the building can greatly affect its acoustic properties; thus, it is

advisable to use sound absorbent materials as finishes. In the Advancement Centre, the

choice of tiles as the floor finish poses an acoustic problem due to its hard, reflective

surface as it increases the reverberation effect in the room, this does not favour the

acoustic characteristic in the space.

The wall finish used in the building is emulsion paint on rendered block wall. The block

wall has a poor acoustic property. Cement plaster has a low absorption coefficient, 0.03 at

1000Hz. A soft porous covering is sometimes used to aid absorption.

Asbestos ceiling sheets was used as the ceiling finish in all part of the building. This is

not a positively inclined acoustic material due to its hard and smooth surface. However,

due to the small-sized nature of the spaces in this building, the acoustic importance of the

ceiling is less important as compared with other finishes in the rooms.


It can be deduced from these points above that the major finishes used in the building

does not help to attain an excellent acoustic performance considering the fact that its use

as been changed from residential to office use, but the design, orientation and location of

the building, to some extents has helped reduce the problem of noise.

4.0 ACOUSTICS IMPROVEMENT OF THE BUILDING

The approaches to the improvement of the acoustic environment of the building can be

highlighted under the two categories of noise sources i.e. outdoor and indoor noise. These

suggested approaches are proffered in a bid to reduce noise levels to tolerable or barest

minimum levels.

4.1 PROPOSAL FOR REDUCTION OF INDOOR NOISE

The following are the proposed ways in which indoor noise can be further reduced in the

Advancement Centre building.

Use of Absorbent Screens and Surfaces

Absorbent materials and surfaces are efficient in reducing noise ensuing from air borne

sound such as human voices as well as any other internally generated noise that would

have been aggravated by multiple reflections from surfaces. The following available

types of sound absorbers could be used:

1. Porous absorbents

2. Membrane absorbents

3. Resonant absorbers

4 .Perforated panel absorbents.

4.2 PROPOSAL FOR REDUCTION OF OUTDOOR NOISE

Suggested ways for further reduction of outdoor noise in the Advancement Centre

building are:

Screening

Higher shrubs can be planted along the access road to aid acoustic serenity which would

further reduce noise from generated from the road users., as well as air borne noise.

Insulation

This can be useful in reducing the noise coming from the road. An insulating material can

be embedded between the existing wall facing the road directly and a new one to be

constructed directly behind it; the resulting insulated double skin wall offers a greater

insulation from traffic noise. To make this approach more workable, the front door will

have to be permanently closed or better still, changed to a double glazed aluminum

framed door provided with door closers to ensure that it is closed after each use to

disallow noise infiltration.


5.0 RECCOMMENDATION

In order to improve the acoustic of this building there should be an improvement on the

wall by using of the above mentioned sound proofing material

5.1 CONCLUSION

Noise control is a subject, which should be given prime consideration in any

environment, whether academic, residential or administrative; most environments require

a serenity to aid the concentration of the users. Beside the spatial requirements needed for

the functionality of the building, other factors such as construction materials, site zoning,

and design are equally significant and these should be sufficiently incorporated in the

design process to assist in the resolution of acoustic problems.

In addition, it should be noted that the acoustic management of a building is to be taken

into consideration before the implementation of project since it is so costly to amend the

construction after the building has been completed. If we discover that the acoustic effect

of a building is not up to an appreciable level, the wall surface may be acoustically

treated with sound-absorbing materials.

Finally, an acoustic consultant should be employed both in new design and existing

renovations of facilities. It is often observed that this aspect of the design is often

neglected and it proves to be detrimental in the end because acoustic problems are

generated at a later phase.

REFERENCES.

Professor Olu OlaOgunsote. Acoustics and Noise Control Lecture notes

Ivor H. Seeley,(1974); Building Technology, sound insulation pp 276.

Effions-Williams J. (1997):McGraw Hill Encyclopedia of Science and

Technology: Acoustical noise, pub McGraw Hill Book company 8th

edition, vol. 1

pp. 76 – 87.

www.sdngnet.com

www.google.ca/acoustic control_in public building.

http://www.sdngnet.com/

http://www.google.ca/acoustic

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