THE ACOUSTIC ANALYSIS OF FUTA GEOTECHNICAL...

Acoustic Analysis of FUTA Geotechnical Laboratory

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


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


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


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.


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.


PLATE 2: FLOOR AND CEILING PLAN OF THE LABORATORY

PLATE 2: SECTION THROUGH THE BUILDING


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


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.


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.


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


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


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

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.

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

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.

http://www.sdngnet.com/

http://www.google.ca/acoustic

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