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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: 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: 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 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