Download acoustics and noise control

AN ASSIGNMENT
ON
ACOUSTIC ANALYSIS OF ENTREPRENEURSHIP BUILDING
COMPILED BY
AJAEGBU C. U. ARC/10/1092
ADEOSUN O. A. ARC/10/1082
COURSE
ARC 507
ENVIRONMENTAL CONTROL III
(ACOUSTICS AND NOISE CONTROL)
SUBMITTED TO
THE DEPARTMENT OF ARCHITECTURE,
SCHOOL OF ENVIRONMENTAL TECHNOLOGY,
FEDERAL UNIVERSITY OF TECHNOLOGY,
AKURE, ONDO STATE, NIGERIA.
IN PARTIAL FULFILMENT FOR THE AWARD OF
BACHELOR OF TECHNOLOGY (B.TECH)
IN ARCHITECTURE.
JULY, 2014
INRODUCTION
Acoustics is defined as the scientific study of sound. Noise on the other hand is defined as any
unwanted sound or damaging sound, that is, sound which interferes with what people are trying
to do, or sound which has an adverse effect on health or safety. The study of sound covers two
major areas which are room acoustics and control of noise. Noise is generated from various
sources and carried through different mediums which can be through air, water or metal.
An analysis was carried out on the Entrepreneurship Building in the Federal University of
Technology, Akure. This analysis is aimed at assessing the acoustic characteristics of the
building, determining the various sources of internal and external noise, and possibly profer
solutions to improving the acoustic properties of the building.
The entrepreneurship building is located in the Obanla campus of the university. Adjacent to it
on both sides is the University Bookshop, and the Digital Research and Resource Sharing Centre.
On the right side is the Technology Museum and on the far right is the library extension under
construction.
The building, though it is not very big, has within it, a circle – shaped courtyard. It is a single
volume building has the shape of an arc, which is meant for office use only.
CHARACTERISTICS OF THE ENTREPRENERURSHIP BUILDING

WALLS
The wall which is a major element of the building serves the dual purpose of providing a frame
for the building and it also provides an enclosed and defined/specific space within the building. It
is made up of sandcrete blocks. The exterior and interior surfaces were finished with cement
screed, and painted with emulsion paint. Sound absorbers were not applied to the walls to
prevent noise from entering into the building.

FLOOR
The floor of the corridor is covered with ceramic floor tiles which help to reduce vibration noise.
Rugs are used in some offices however. These rugs also serve as sound absorbers.

CEILING
The ceiling which is about 3 metres in height, and all around the building, the ceiling material
used is asbestos.

EXTERNAL SURROUNDING
The entrepreneurship building is surrounded by various buildings. There is an access road in
front of the building. However, there is no provision for car park in the vicinity, thereby making
vehicle owners and users park their cars on the sides of the road. On the left side and at the back
of the entrepreneurship building is an undeveloped site. There is a walkway access directly from
the road leading to the building. The building has shrubs and flowers surrounding it and also on
both sides of the walkway, as well as a grass lawn in front of the building.
Picture showing entrance of the building
Pictures showing courtyard inside the building and structures to the right of the building
Pictures showing access road in front of the building and adjacent structure
Pictures showing ceramic floor tiles used as floor finish and asbestos ceiling material
SOURCES OF INTERNAL AND EXTERNAL NOISE
There are various sources of noise. During this study, a number of sources were identified.
SOURCES OF INTERNAL NOISE
The sources of internal noise identified include:


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Conversations from passers-by in lobby and adjoining offices.
Electrical appliances like outdoor air conditioning units, ceiling fans, computer systems
and laptops.
Generators
Picture showing a source of internal noise: an outdoor A.C unit
SOURCES OF EXTERNAL NOISE
These include:



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Vehicular noise generated from the major road.
Pedestrians and passers-by
Generator sets
Activities ongoing in surrounding buildings.
Pictures showing some the access road and generator set as sources of external noise
picture of site showing noise sources
PERCEPTUAL ASSESSMENT OF THE ACOUSTIC CHARACTERISTICS OF THE
ENTREPRENEURSHIP BUILDING
A person’s perception of noise differs at various levels depending on he/she’s exposure to a kind
of activity. The entrepreneurship building which is not a very large structure is built within a
supposed serene and semi-quiet environment. There are various offices within the building
which does not allow for loitering around.
Generally evaluating, there is not much noise control measure put in place to make daily
activities more comfortable for the occupants.
A major source of internal noise identified is conversations from people in the lobby and also in
the various offices.
The building is mostly affected by external noise coming from cars parked on the sides of the
access road and also the road users. This road happens to be a major route linking other parts of
the school. Another source of external noise identified is a generator which is the alternative
source of power supply. At the time of use, it was placed behind an exit to the building, thereby
generating a lot of noise.
PROPOSAL FOR IMPROVING ACOUSTICS OF ACADEMIC BUILDING BY
AMELIORATING INTERNAL AND EXTERNAL NOISE
Noise cannot be eliminated; however, control measures can be put in place to improve the
acoustic properties of the building, thereby reducing the noise to the barest minimum.
INTERNAL NOISE
Control of internal noise can be achieved by the following


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Use of absorbent screens
Insulation
Reduction at source
Use of Absorbent Screens
It is always advisable to use wall finishes that serve as screens, because they help in either the
absorption or reflection of sound. Materials such as wood panels and padded rugs can also serve
as good absorbers of sound.
Insulation
In order to achieve proper noise control, equipment that generate a high level of noise can be
insulated by putting them far away from the buildings. An example of such equipment is a
generator.
Reduction at Source
This is mostly applicable to household appliances; however, in the case of airborne sound, an
insulating enclosure around the source is advisable.
EXTERNAL NOISE
External noise has its sources outside the building. As identified above, these sources include
roads, vehicles, and adjoining structures. Some measures used in controlling external noise could
be applied to the following:

Windows
In order to reduce external noise, the windows of the building could be treated specially, by
making them double – glazing.

Doors
There are various forms of sound proof doors that can be used to reduce noise. The materials of
such doors also help to determine their acoustic properties.

Roof
Roofing materials that are lightweight are easily penetrable by noise. This can be reduced by the
use of insulation layers on the top of the ceiling, with an air gap between the insulation layer and
the roof material. Another method of noise control via the roof is to introduce flat roofs. These
are mostly made of reinforced concrete.

Site Planning and Location
This plays an important role in noise control. Location of buildings should be far away from
noise sources. Buildings that are to be used for noise related activities should be sited farther
away. Noise generated from the road cannot be controlled, however, provision of a suitable car
park should be made to ease movement on the road and also avoid congestion. Also, planting of
more trees, shrubs, plants and green areas should be done, because they act as sound buffers and
help to shield the building from noise.
REFERENCE

ARC 507 lesson notes, Basic Concepts in Architectural Acoustics