ACOUSTIC ANALYSIS
OF
THE POST GRADUATE RESEARCH LABORATORY PHASE2
FEDERAL UNIVERSITY OFTECHNOLOGY
AKURE, ONDO STATE.
COMPILED BY:
ORIMOLOYE IDOWU S. ARC/09/7423.
POPOOLA AYOBAMI ARC/O9/7426.
IN PARTIAL FULFILMENT OF ARC 507 (ENVIRONMENTAL CONTROL) ACOUSTICS AND NOISE CONTROL
LECTURER IN CHARGE:
PROF. OGUNSOTE
JULY, 2014.
TABLE OF CONTENT
1.0 INTRODUCTION
2.0 GENERAL DESCRIPTION OF THE BUILDING COMPONENTS FINISHES.
2.1THE FLOOR FINISHES
2.2 THE WALL FINISHES
2.3 THE CEILING FINISHES
3.0 CLOUD COMPUTING LABORATORY
4.0 ANALYSIS OF SOURCES OF NOISE
4.1 EXTERNAL SOURCE
4.2 THE INTERNAL SOURCE
5.0 ACOUSTICS CHARACTERISTICS OF THE LABORATORY
5.1 BACKGROUNG NOISE
5.2 REVERBERATION
5.3 ECHOES
5.4 LOUDNESS OF ORIGINAL SOUND
6. 0 PROPOSED WAY OF IMPROVING THE ACOUSTIC OF THE POST GRADUATE RESEARCH LABORATORY BUILDING.
1.0 INTRODUCTION
NAME: post graduate research laboratory phase 2
LOCATION: The building is located along the newly recently created traffic axis along the newly built School of Management Technology building and other research buildings following the School of Mineral sciences building and immediately at the back of the school of post graduate studies in the Federal University of Technology,Akure,Ondo State, Nigeria.
INTRODUCTION
The building was officially commissioned on the 24th day of November, 2010. This building was constructed purposely to serve as an extension of the original school of postgraduate studies, thus its location.It serves as a part of statement of intent from the school administration on its mission of improving the schools standings in the community of international universities. The building currently has spaces given out to departments Quantity surveying, Exon-Mobil Geosciences laboratory, cloud computing laboratory, physics P.G. research laboratory, Chevron Geosciences laboratory, ICT Laboratory (QSV). This consists of a storey building that has two wings with a center circulation with a stair well on each wing end and a central one.
2.0 GENERAL DESCRIPTION OF THE BUILDING COMPONENTS FINISHES.
For the purpose of this assessment, we will briefly describe the finishes of three major components of this building: the floor, wall and ceiling finishes.
Cad file showing the building and it’s surrounding
2.1 THE FLOOR FINISHES.
Generally, the main floor finishes used throughout the building was THE ceramic floortiles finishes. The tiles are made from ceramic, a building material reknowned for its easy availability and relative stability. In this building, the entire floor area was covered with this floor tiles, of 400mmx400mm size each. The floors of some offices were carpeted while others were rugged.
2.2 THE WALL FINISHES
The walling material used was hollow concrete block wall supported with reinforced concrete column of considerable size. The walls were plastered with a ‘cement plaster’. Cement plaster is a mixture of cement and sand, usually mixed in ratio of 1:3 or 1:4 which forms a very hard surface as it sets. The sand used for plastering should be clean, coarse and angular. Soft sand is always preferable. This was used to cover both external and internal surfaces of the walls.
Then the external walls surfaces were covered with texcote paint to give extra protection against the penetration of moisture and to provide a decorative effect for the viewers. The paints were of different colors.
Also, the internal surfaces of wall were painted with different color of emulsion paints.
2.3 THE CEILING FINISHES.
The whole first floor ceiling area are covered withpvcroof materials both the ground and first floor. Woods were used for noggins, struts and battens. The ground floor is covered with the suspended floor slab as the ceiling material.
FRONT VIEW
REAR VIEW
3.0 CLOUD COMPUTING LABORATORY.
Cads file representing the floor plan of the laboratory
The selected area for this study is the Cloud Computing Laboratory. The laboratory is located at one side of the building the farthest educational room on the left wing upper floor.
The walls finishes were as described above for both external and internal wall surfaces. Floor finishes used is ceramic tiles and it was done as described above with skirting made of the same materials. Also, the ceiling finishes used was asbestos sheets of 1200mm by 1200mm sizes painted with white emulsion paints as described in (2.3) above.
Cads file representing the ceiling plan
Cads file representing the section of the lab
Cads file representing the section of the lab
4.0 ANALYSIS OF SOURCES OF NOISE.
This analysis will be majorly focused on the cloud computing laboratory as a result of largeness of the building. The analysis is carried out on two sources: External and Internal sources of noise.
4.1 EXTERNAL SOURCE
The main external noise to the building is from vehicles and students hovering around the building as shown in the building surrounding plan represented above.
The car parks are large and close to the building without buffer zone. The vehicles coming in and out of the parks produce some noise which is generally transmitted into the building interiors through walls and windowsopenings. For the laboratory, transmission of this vehicular noise is mainly through the walls and fenestrations which include the sliding windows and the clerestories above them. Also the building is along a road axis though the setback which is around 45m has and will continue to serve as a source of noise reductionlevelsas a result.
Even at the circulation area where students normally wait, there is also an opening to the lab at that side, this includes the paneled door and the sliding windows with aluminum mullions.. The only noise from students is that which comes directly from the students sitting on the corridors and walking along the corridors.
The architect who designed this building has done a good job in zoning arrangement firstly in setting back the building as far as possible from the road to avoid vehicular traffic disturbance and also located the laboratory at the extreme end of the building away from other functions thereby reducing noise effect from student from other rooms.
Even at the circulation area where students normally wait, there is no any opening to the lab at that side. The only noise from students is that which comes directly from the students standing immediately beside the windows maybe leaning on the railings to enjoy the greenery view that the lab faces.
4.2 THE INTERNAL SOURCE
The source of internal noise in the cloud computing lab is mainly from the students inside and their electronics (laptops and mouse) or equipment. Also there is noise from ceiling fans and from people walking in the studio.
Cads file showing the Omni-directional sound from the main source
5.0 ACOUSTICS CHARACTERISTICS OF THE LABORATORY
This involves the assessments of the sound and its behavior in the studio. The acoustic characteristic of this studio is considered under the following: background noise, reverberation and echoes.
5.1 BACKGROUNG NOISE
This is the normal prevailing ambient noise from many sources including street traffic and outdoor noise in general which has been reduced with the distance to the road. Other sources include air-conditioning equipment, structural borne noise from mechanical equipment, noise from adjoining rooms and noise from the audience itself. Such background noise may reduce speech intelligibility and cause serious distraction in listening to music.
In the early hour of the days the general background noise of the lab is low. This is because the traffic on the road and at the car park will be light and no students waiting around the lab. Therefore the lecturer needs not to shout before the students can hear his/her voice clearly at this period.
5.2 REVERBERATION
Reverberation is the persistence of sound in an enclosed space as a result of a repeated reflection or scattering after the sound source has stopped. When the sound is produced in this laboratory, the sound waves spread from the source in spherical pattern .When these waves strike a surface e.g. wall surface, some will be reflected back .This reflected sound continues spreading until it strikes another surface which reflects again and so on This continues even after the actual source has ceased producing sound However, some of sound is absorbed at every reflection and the sound energy reduces progressively until the sound becomes inaudible. Therefore reverberation time is the time required for the sound level in the room to decay 60dB. In other word ,it is the time needed for a loud sound to be inaudible after turning off the sound source .The reverberation time is directly proportional to the volume of the room and is given by :
t = 0.05v/A.
Where:
t= reverberation of the sound
v=volume of the room
A=total room absorption
The total absorption in a room is found by adding the absorption of the surface, the seats and the audience. The ideal reverberation time for speech is about one second and the maximum acceptable time is about two seconds.
The size of the room will affect the reverberation time .When the room is so large that the reverberation time is above acceptable limits, the surface should be acoustically treated with sound absorbent materials. Large curved surfaces tend to focus sound and cease an even distribution of sound .Thus high curved ceilings or curved rear walls in along room should be avoided. In general, a room of rectangular shape is preferable.
The size of this lab is not too large and none of the ceiling and wall surfaces is curved. Therefore its optimum reverberation time is between one and two which makes it adequately suitable.
5.3 ECHOES
An echo is a distinct repetition of a direct sound. This effect may be observed by making a short sound, such as a sharp clap in a large room. It is a consequence of the reflection of sound.
Due to the adequate window openings and size of the laboratory, the echo effect in this studio is very minimal.
5.4 LOUDNESS OF ORIGINAL SOUND
Intelligibility of speech increases with loudness .In large rooms, it is often necessary to use public address system for amplification .In this distortion of speech by the equipment should be avoided. But in this laboratory there is no public address system and the area is relatively small so the need doesn’t arise at all.
6. 0 PROPOSED WAY OF IMPROVING THE ACOUSTIC OF THE POST GRADUATE RESEARCH LABORATORY BUILDING.
One of the ways that the acoustics of the room picked nad the building as a whole can be improved is by the planting of trees along the setbacks already set to the road
Another way is to use acoustically sound ceilings and doors with good paneling