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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
Acoustic Analysis Of Advancement Centre Page 3
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).
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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.
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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.
Acoustic Analysis Of Advancement Centre Page 6
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
Acoustic Analysis Of Advancement Centre Page 7
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.
Acoustic Analysis Of Advancement Centre Page 8
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
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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.
Acoustic Analysis Of Advancement Centre Page 10
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.
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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.
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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.