A
TECHNICAL REPORT
ON
THE ACOUSTIC ANALYSIS OF
FUTA GEOTECHNICAL LABORATORY
CARRIED OUT BY
SOMOTUN BOLANLE A
ARC/10/1177
&
ADESEYE ABIODUN O
ARC/08/3967
LECTURERS-IN-CHARGE
PROF. O.O OGUNSOTE
ARC S.A GANIYU
SUBMITTED TO
THE DEPARTMENT OF ARCHITECTURE
IN PARTIAL FULFILLMENT OF THE COURSE,
ENVIROMENTAL CONTROL III
(ACOUSTIC AND NOISE CONTROL)
(ARC 507)
JULY, 2014
Acoustic Analysis of FUTA Geotechnical Laboratory Page 1
TABLE OF CONTENT
CHAPTER ONE
1.0 INTRODUCTION
1.1 AIM AND OBJECTIVE
1.2 LIMITATION OF ANALYSIS
CHAPTER TWO
2.0 GENERAL DESCRIPTION OF FUTA GEOTECHNICAL LABOURATORY
2.1 ARCHITECTURAL DESIGN
2.2 MATERIAL ANALYSIS
2.2.1 Floor
2.2.2 Wall
2.2.3 Ceiling
2.1.3 Opening
CHAPTER THREE
3.0 ANALYSIS OF NOISE
3.1 SOURCE OF INTERNAL NOISE
3.1.1 Measurement of internal noise level
3.2 SOURCE OF EXTERNAL NOISE
3.2.1 Measurement of external noise level
3.3 FACTORS AFFECTING ACOUSTIC OF GEOTECHNICAL LAB
3.4 ACOUSTIC CHARACTERISTICS OF GEOTECHNICAL LAB
3.4.1 Background Noise
3.4.2 Reverberation
3.4.3 Echo
3.5 PROPOSAL FOR REDUCTION OF NOISE
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CHAPTER FOUR
4.0 CONCLUSION AND REFERENCES
CHAPTER ONE
1.0 INTRODUCTION
The influence of acoustics on the design of buildings can be observed through the
ages from Roman amphitheatres to the modern houses or buildings in which we spend our
working hours and our leisure. The great difference, however, between life in ancient Rome
and life in our crowded modern cities is the presence of noise from an ever increasing
number of sources from neighbours traffic and industry.
Consequently, the science of building acoustics used to be a major consideration
especially when designing classrooms and auditoriums as studies indicated that poor
acoustics interfere with learning and pose a particular barrier for students with special needs.
However, acoustic analysis is no longer limited to the acoustic design of theatres,
classrooms and auditorium but has increased in scope to cover noise control and abatement
in all types of buildings
Acoustic is one of the factors that that most affects the deterioration of
environmental quality one that may generate discomfort to the occupants of a building.
Acoustics levels can be a key element of high performance indoor environment quality
where building occupants are comfortable and productive.
Acoustic analysis takes into account the study of sound in a given space its
transmission, the intelligibility of voices and the levels of ambient sound inside the space.
1.1 AIM AND OBJECTIVE
This report is a study of FUTA GEOTECHNICAL LABOURATORY, located in the
Federal University of Technology, Akure. It aims at examining the building’s acoustics
conditions with a lucid explanation of the effect of building’s size, its characteristic shape,
and use of materials in effectively enhancing speech clarity and combating noise problems
in order to ensure satisfaction for the users.
Every element of building design and construction affect its acoustical
characteristics. These elements include walls, furniture, windows, ceiling etc. A study of the
acoustic components of a building is essential to addressing the problems associated with
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sound. There are two main sources of noise – internal and external sources. These will be
looked into in the course of this write-up.
1.2 LIMITATION OF ANALYSIS
The problems encountered during analysis were:
1. The unavailability of Spectrum analyzer and true RTA software needed to use to
carry out the real time analysis of the audio signal. This could have being done by
sending signal to true RTA software and show analysis on the spectrum analyzer.
2. . The objective room-acoustic parameters such as reverberation time (RT), early
decay time (EDT), clarity factor (C80), strength (G) and lateral energy fraction
(LEF) could not be determined.
CHAPTER TWO
2.0 GENERAL DESCRIPTION OF FUTA GEOTECHNICAL LABOURATORY
The Geotechnical laboratory is one of the technical laboratories of the Federal
University of Technology Akure,sited at the Obanla campus of the university, it is some
metres away for the school of sciences and some metres away from the academic building.
The building is surrounded with the academic building, the mechanical engineering
workshop, electrical/electronic department workshop on the east, north and west
respectively.
The Geotechnical laboratory was built majorly to carry out experiments related to
construction materials tests majorly for the civil engineering students, and offices for the
laboratory attendants, technologist and lecturers.
Due to the activities that are carried out in the laboratory, it is also a major source of noise.
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PLATE 1: THE GEOTECHNICAL LABORATORY BUILDING
2.1 ARCHITECTURAL DESIGN
The geotechnical laboratory was commissioned in November 2008, by the former
Niger state governor,Alhaji Kure, the building was built in order to carter for the students of
the university need(s) to carry out necessary experiments/test majorly construction
engineering tests. The building is a purposely built workshop maintaining a regular
rectangular shape consisting of working area,offices,conviniencies,few parking spaces are
located in front of the building, just before the parking is a pedestrian walkway accessing
the building on the front side of the building, and shrubs separating the walkway from the
parking lots.
The building is designed with series of gable roof, one higher than the other, due to
the increase in height of the headroom of the working area in order to accommodate high
level windows which serves as a means of illumination and ventilation on the interior of the
working area.
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PLATE 2: FLOOR AND CEILING PLAN OF THE LABORATORY
PLATE 2: SECTION THROUGH THE BUILDING
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PLATE 2: SORROUNDING SITE PLAN
2.2 MATERIALS ANALYSIS
2.2.1 FLOOR
The floor of the laboratory is finished with 1200x1200mm in-situ terrazzo floor finish.
Terrazzo does not have good acoustic property in that it does help to reduce the level of
noise.
Plate 3: the terrazzo floor finish
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2.2.2 WALLS
225mm x 225mm x 450mm sandcrete hollow block wall rendered with cement mortar and
finished with dark beige colour emulsion paint.
Plate 4: walls of the building finished with emulsion paint
2.2.3 CEILING
Ceiling finishes used in the space is 1200mmX1200mm white painted asbestos
ceiling boards running through the whole space though recessed at some points
2.2.4 OPENINGS
Doors are made of hardwood timber panel door with steel burglary proof while
windows are 1800mm X1500mm louvre window with louver blades and tubular steel
burglary proof.
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PLATE 5: OPENINGS PLATE 6: CEILING FINISHES
CHAPTER THREE
3.0 ANALYSIS OF NOISES
Noise is said to be an unwanted sound which bring about discomfort to human.
Noise source in a space is generally categorised into 2 major sources,viz;
Internal source
External source
3.1 SOURCES OF INTERNAL NOISE INCLUDE:
The major sources of internal noise include
I. Fans: fan noise is due to the rotational movement of the fan blades and speed of
the fans and some of the fans make noise due to the fact that they are not in good
shape.
II. User’s activities: users of the building also generate noise through verbal
communication amongst them and also movement about the space since the floor
finish used is terrazzo and terrazzo is not a good sound insulator.
III. Machines: since it is a laboratory, different activities are expected to going on
there, in the process of carrying out these activities machines are used thereby
generating a large volume of noise in the space.
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Other sources of internal noise includes impact sounds such as movement of
users and furniture within the space, swinging and banging movement of doors e.t.c
PLATE 7:SOURCES OF INTERNAL NOISE;FANS,MACHINE,FURNITURE
3.1.1 MEASUREMENT OF INTERIOR NOISE LEVEL
Different noise levels were recorded within the interior space of the
laboratory due to varying level of activities going on, the noise level recorded is
more of noise generated from users of the building and other sources apart from
machine noise because machine activities were not going on as at the time this
analysis was done.
The instrument used is a mobile noise level meter. The noise level recorded
was between the range of 80-87dB
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PLATE 8: RECORDINGS FROM SOUND LEVEL METER
3.2 SOURCES OF EXTERNAL NOISE INCLUDE
The sources of external noise of every building includes its surrounding activities,
buildings e.tc.The sources of external noise noted for the geotechnical laboratory
include:
Noise from nearby mechanical engineering department workshop
Vehicular noise as a result of driveway and parking lots around the building
Noise from generator
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PLATE 9: SOURCES OF EXTERNAL NOISE
3.2.1 MEASUREMENT OF EXTERIOR NOISE LEVEL
The noise level recorded on the exterior of the building falls within 91-105dB
PLATE 10: RECORDINGS FOR EXTERNAL NOISE LEVEL
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3.3 FACTORS AFFECTING THE ACOUSTICS OF GEOTECHNICAL LAB
SIZE AND SHAPE
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 geotechnical laboratory,
the regular rectangular shape and size of the spaces in the building define an excellent
acoustic characteristic.The size of the space will still produce an acceptable reverberation
time .
FINISHES
The finishes used in a space greatly affect its acoustic properties; however, it is
advisable to use sound absorbent materials as finishes. The use of terrazzo isn’t really a
good choice of material to use when considering acoustic, rugs can be introduced to reduce
the noise generated from the floor.
Sandcrete hollow block wall isn’t a good absorber of sound wave, it posses a very
high reflective property. A soft porous absorbers pad can be introduced to walls to aid
absorption.
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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. Absorbers can also
be introduced to reduce the reflective properties of the ceiling.
3.4 THE ACOUSTIC CHARACTERISTICS OF THE GEOTECHNICAL
LABORATORY
3.4.1 Background Noise
Background noise from activities of students around and adjoining facility as well as
vehicular noise are properly shielded from the building. Through screening of the parking lots with
shrubs and hedges.
3.4.2 Reverberation
Highly reflective materials, terrazzo floor finish, asbestos ceiling, sandcrete block walls, and
windows increase the reverberation time. Absorptive materials, such as curtains, heavy carpet, and
people, reduce the reverberation. Bigger rooms tend to have longer reverberation times. However,
reverberation in the geotechnical lab is still on the bearable side.
3.4.3 Echo
Due to the large volume of the space and the nature of materials that encloses the space echo level
tends to be on the high side.
3.5 PROPOSAL FOR REDUCTION OF NOISE
The following are proposed ways in which noise can be reduced in the geotechnical lab
3.5.1 Introduction of Rugs on Floor
Impact noise such as furniture movement, banging of doors and footsteps are less in carpeted rooms
as compared to rooms with hard floor finish. Introduction of rugs on the floor helps to reduce the
Noise level in the laboratory.
3.5.2 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 as a result of
multiple reflections from surfaces.
3.5.3 Reduction of Mechanical Noise
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Noise as a result of moving machine parts can be reduced with the application of lubricants to the
moving parts. Shock absorbers can be introduced to vibrating machine part.
3.5.4 Screening
Shrubs and hedges can be used a buffers to shield away noise coming from the parking lot to aid
acoustic serenity
CHAPTER FOUR
4.0 CONCLUSION.
Noise control is a major factor, which should be given prime consideration in any academic and
administrative environment; most aspects of learning require a serene environment to aid the
concentration of the users. Aside the spatial requirements, 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.
Finally, an acoustic consultant should be included in both new and remodelled learning facilities to
aid a suitable learning environment. In a bid to reduce construction cost, this aspect of the design is
often neglected, and more often than not, it proves to be detrimental in the end because acoustic
problems are generated at a later phase. In treating these problems, much more than would have been
necessary (if it had been addressed at an early stage by a consultant) is spent.
REFERENCES.
Professor Olu OlaOgunsote. Acoustics and Noise Control Lecture notes
Ivor H. Seeley,(1974); Building Technology, sound insulation pp 276.
www.sdngnet.com
www.google.ca/acoustic control_in public building.
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