web view(dr) bubar abba ibrahim . lecture complex. compiled. by. babatola . o. o. arc/10/1116....
TRANSCRIPT
ACOUSTIC ANALYSIS
OF
SEN. (DR) BUBAR ABBA IBRAHIM
LECTURE COMPLEX
COMPILED
BY
BABATOLA O.O. ARC/10/1116
ILESANMI L. A. ARC/10/1130
SUBMITTED TO
THE DEPARTMENT OF ARCHITECTURE
FEDERAL UNIVERSITY OF TECHNOLOGY,
AKURE, ONDO-STATE
LECTURER-IN-CHARGE
PROF O.O. OGUNSOTE
ARC GANIYU
July, 2014
INTRODUCTION
The term acoustics can be defined as the science of sound control with consideration to the
interior and exterior components and features of a building.
The primary means of communication in most educational settings are speech and listening. The
acoustics of the lecture room can support the speaker by improving the level and the
intelligibility of speech – or the opposite. The room acoustics in lecture rooms is therefore an
important issue when considering the productivity and working environment in schools and other
teaching situations
The presence of electronics and computer has immensely increased our measuring ability with
great accuracy. Analyzing techniques that could have only been put to use about years back are
now common-place. However, the inadequacy of analyzing capability in the past has led to a
particular architectural quality of buildings and rooms that are poor acoustically in relation to
their intended purposes. The shape, construction type and dimension and the content of a room
will determine the rate of sound transmission, sound reflection and absorption in such enclosed
space.
DESCRIPTION
The lecture room is partitioned into three different lecture spaces using plywood and each lecture
rooms are essential spaces for communication considering the acoustic attribute of the spaces.
Architecturally, the importance is based on sufficient audibility of the space.
The acoustic nature of a lecture room, being an enclosed room where lectures, seminars and
even defense are held, can also result in disturbance and acoustical challenge.
A lecture room is more efficient when the sound from inner and outer part of the space is
minimal. To and fro movement of people around the building is a typical source of external noise
to the building which will result in distraction or disruption of full concentration on the ongoing
activity.
The lecture room to be analyzed is located beside and behind the 2 in 1 lecture theatre and the
School of Earth and Mineral Science respectively at Obanla campus of the Federal University of
Technology, Akure.
The selected lecture room has a rectangular shape with the one on the left facing the parking lot
directly while the other wing on the right is facing the walkway from the SEMS building to the
extension building.
COMPONENTS OF THE LECTURE ROOM:-
i. Aluminum window frame with sliding glass sash window
ii. 225mm thick Sandcrete hollow block walls rendered with cement and sand
mix, painted with whitish-yellow emulsion paint.
iii. Asbestos ceiling sheets etc.
iv. Steel panel double swing door
v. Polished ceramic tile floor finish
Pictures showing the steel panel door
picture showing the aluminum frame with sliding glass sash window
Pictures showing the polished ceramic tile floor finish
Picture showing the asbestos ceiling sheets etc.
EXTERIOR ELEVATION OF THE SELECTED SPACE
Picture showing the approach view of the selected space
Picture showing the left approach the building
INTERIOR ELEVATIONS OF THE SELECTED SPACE
Pictures showing the right and left view of the selected space in the building
Pic
Picture showing the front and back view of the selected space in the building
ACOUSTIC ANALYSIS OF SEN (DR) BUBAR ABBA IBRAHIM
LECTUREROOM
Firstly it is necessary to identify the acoustic problems of the above space. The problems can
be perceived in two ways external and internal.
.EXTERNAL ACOUSTIC PROBLEMS
The table below show the sources of noise in relation, the original noise level from the near
field in decibel barrier impact and the noise level of reverberant field which is the lecture
room, the building encounter some acoustic challenges which is as a result of the following:
I .Its location, surrounding
II. Features and
III. Human activities e.g. sound from the students and staff passing by and also noise from
the car park (vehicular movement which serves as source of external noise to the lecture
Vehicular noise: Vehicular movement from the car park is one of the major sources of
external noise to the building.
Human activities: activities from the adjacent buildings serves as a source of external noise
to either wings of the building and also another source of noise is from the to and fro
movement of students and staffs, their footsteps sound, background noise is also a primary
source of external noise to the building. The diagram below shows the impact of external
noise on the occupant of the building
Site plan showing the noise source
Floor plan of the selected space
Walkways which is the major source human external noise
SECTION X-X OF SEN (DR) BUBAR ABBA LECTURE ROOM
Picture showing the car park where the vehicular noises come from
INTERNAL ACOUSTIC PROBLEMS
The dimension, finishes and shape are the interior properties that determine the sound reflection
or absorption rate of the space. Background noise from students within each lecture spaces of the
building and also noise from movement of furniture within room is also a problem of internal
perception of noise. The following are the content of the lecture room and how they affect the
acoustic of the space.
i. Walls: The wall is 225 mm thick rendered and finished with a whitish-yellow paint, it
will b just a little bit effect in reduction of the noise
ii. Openings: The windows are 2100mmx 1200mm which make it easier for th
penetration of noise into the building and also the door is a 1800mmx2100mm steel
framed door. Which also contribute to the noise within when opened of closed,
therefore the entrance of a student of staff during a lecture will result in distraction or
a break in the lecture
iii. Floor finish: Floor finish as stated earlier is a polished ceramic tile floor finish which
will only contribute to the poor acoustics of the building through the sound it makes from
footsteps of a student or staff in motion within the selected space
iv. Furniture and fittings: The furniture in the space are combination of wood and steel
and therefore can a source of internal noise.
v. Ceiling: the Ceiling is asbestos and therefore has no contribution in the reduction of
the noise. There are ceiling fans hung to the ceiling which are also sources of internal
noise
A PERCEPTUAL ASSESSMENT OF THE ACOUSTIC CHARACTERISTICS
OF THE SELECTED SPACE
We shall describe the characteristics of the space acoustically under the headings
below which are:
I. The Background noise
II. Reverberation and Echoes
Background Noise
vi. The Background noise has been reduced to a reasonable extent, with the use of fins
at the windows at interval of3 meters it also serve as a shading device for the space
and also dampen the intensity of the sounds coming from external sources
vii. The quick elimination of unnecessary external activities like chatting, wondering
during working hours is still achievable.
viii. From car park, and noise from adjoining building, like the SEMS building and
extension, walkways that link them, and the 2in 1 to create an conducive learning
environment.
Reverberations and Echoes
ix. The interiors space is such that each listener has its auditory line of perception. Even
if the walls surfaces are smooth and there is possibility of reflection, and also the
reverberation time is such that speech is intelligent in the building.
x. The materials used in the interior space are not very inclined acoustically.
xi. However, due to the size of the space, It is worthy of note that echoes aren’t usually
experienced.
PROPOSAL FOR ACOUSTIC IMPROVEMENT OF SEN. (DR) BUBAR ABBA
LECTURE ROOM
The acoustics condition of a selected lecture space in the Sen. (DR) Bubar Abba Ibrahim lecture
theatre as been analyzed showing the materials and their acoustic value and attributes and we
also pointed out both the external and internal noise source to the selected space
Screening:
With the use of Absorbent materials and surfaces, external noise reduction will be achieved,
There are examples and types of absorbent materials;
i. Porous absorbents (best for high frequencies)
ii. Membrane absorbents (best for low frequencies)
iii. Resonant absorbers (resonators)
i. Installation of Carpet on the Floor
Noise from impacts such as shifting furniture and footsteps are less in rooms with carpet floor
finish compared to rooms with floor tiles finish. Carpets however raise questions on indoor air
quality and high maintenance costs which must be balanced with acoustical benefits.
ii. Use of a Sound System
The use of sound system like the wireless microphone used by the teacher to pick up his voice,
the voice is then amplified and played through a loudspeakers strategically positioned in the
room to enhance speech sounds for the students within the space, this prevents the lecturer from
stressing his or herself to achieve audibility.
iii. Installation of padded furniture
Installation of foam padded and leather finished chairs will help in absorption of some sound.
iv. Installation of double glazed windows
With the size of the window, the best way to achieve noise reduction in that aspect is the through
the installation of double glazed window
4.1 PROPOSAL FOR REDUCTION OF EXTERNAL NOISE
Screening of Building
The noise coming from the surrounding walkways and car park can be screened-off using a using
a transparent insulating material that will not disturb light ray and also trees and shrubs can be
planted to reduce the noise coming from the car park.
Insulation
This will be most effective in the fenestration area of the building with the use of double glass windows
Which reduce noise penetration and also the use of aluminum famed door will be effective in noise
reduction..
Generation of noise reduction laws
Nose reduction laws can be implemented for students and staff movement should be restricted to some
specific areas during working hours.
CONCLUSION
The most importance attribute of a lecture room is for the lecturer or speaker to pass information
to the listeners or audience with ease .considering the acoustic level of the selected portion of the
Sen. (Dr) Bubar Abba Ibrahim Lecture theatre to an extent is conducive considering the position,
but with the above proposal, an acoustic improvement can be achieved.
.
REFERENCE
Professor Olu OlaOgunsote. (2007) Acoustics and Noise Control Lecture notes, 2007
Acoustical Society of America, ASA (2000) ‘Classroom acoustics. A resource for creating learning environments with
desirable listening environment with desirable listening conditions’. 2
Huntington Quadrangle Melville,Ny11747
Jullien J. (August4-6,1986) Measurements of room acoustic quality, The