· Web viewIntensity varies inversely as the square of the distance, provided there is no loss of energy due to viscosity, heat conduction, or other

ACOUSTIC ANALYSIS OF ADVANCEMENT CENTRE

CARRIED OUT

BY

OGA OLUWASEGUN ADEBAYO ARC/10/1139

&

OLADUNNI KABIR AYODEJI ARC/10/1147

COURSE

ENVIROMENTAL CONTROL III (ACOUSTIC AND NOISE CONTROL)

(ARC 507)

LECTURERS

PROF. O.O OGUNSOTE

ARC S.O GANIYU

SUBMITTED TO

THE DEPARTMENT OF ARCHITECTURE

FEDERAL UNIVERSITY OF TECHNOLOGY, AKURE

ONDO STATE, NIGERIA

IN PARTIAL FULLFILMENT OF THE REQUIREMENT FOR THE AWARD OF A BACHELOR OF TECHNOLOGY (B.TECH) IN ARCHITECTURE

JULY 2014.

Acoustics Analysis Of Advancement Centre Page i

Pages

TABLE OF CONTENTS ii

LIST OF PLATES iii

LIST OF FIGURES iii

1.0 INTRODUCTION 1

2.0 LITERATURE REVIEW 2

2.1 S0UND 2

2.2 NOISE 3

2.3 ACOUSTICS 3

3.0 ANALYSIS OF THE ADVANCEMENT CENTRE 4

3.1 ARCHITECTURAL DETAIL/ BRIEF DESCRIPTION OF THE BUILDING

3.2 FINISHING MATERIAL ANALYSIS OF THE BUILDING 4

3.3 FLOOR PLAN OF THE BUILDING SHOWING FURNITURE

ARRANGEMENT AND FLOOR FINISHES. 6

3.4 THE CEILING PLAN OF THE BUILDING 7

3.5 SITE PLAN SHOWING THE SOURCE OF NOISE 7

3.6 PICTURE SHOWING DIFFERENT VIEWS OF THE BUILDING 8

3.7 SOURCES OF NOISE TO THE ADVANCEMENT CENTRE 8

3.8 SOURCES OF INDOOR NOISE 8

3.9 SOURCES OF OUTDOOR NOISE 9

3.10 FACTOR AFFECTING THE ACOUSTICS OF THE ADVANCEMENT

CENTRE 10

4.0 ACOUSTICS IMPROVEMENT OF THE BUILDING 11

4.1 PROPOSAL FOR REDUCTION OF INDOOR NOISE 11

Acoustic Analysis Of Advancement CentrePage ii

4.2 PROPOSAL FOR REDUCTION OF OUTDOOR NOISE 11

5.0 RECCOMMENDATION 12

5.1 CONCLUSION 12

REFERENCES 12

LIST OF PLATES

Plate 1: The internal Wall finished with cream emulsion paint. 4

Plate 2: The asbestos ceiling Finish 5

Plate 3: showing window and door type 5

Plate 4: The ceramic tiles floor Finish. 6

Plate 5: showing different facades of the building 8

Plate 6: the ceiling fan used in the building 9

Plate 7: the interior furniture of the building (receptionist/ waiting area) 9

Plate 8: Access road; a source of outdoor noise 10

LIST OF FIGURES

Fig. 1: Floor plan of the building showing furniture arrangement and floor finishes 6

Fig. 2: Ceiling plan of the building. 7

Fig 3: site plan showing the source of noise. 7

Acoustic Analysis Of Advancement CentrePage iii

1.0 INTRODUCTION

Architectural acoustics encompasses room and auditorium acoustics. Reverberations due to reflections from walls, celieng, and furniture influence room acoustics. For best acoustic qualities, rooms are designed to produce sufficient reflections for naturalness, without introducing excessive reverberation at any frequency, without echoing certain frequencies unnaturally, and without producing undesirable interference effects or distortion. A failure to adhere to these principles of architectural acoustics leads to the generation of unwanted or damaging sound that will adversely affect the activities of intended users when the space is in use.

Sound is a disturbance or wave, which propagates through physical medium such as air or parts of the building structure in a longitudinal manner from the generating source to produce sensation of hearing at the receiving end. Sound waves exhibit reflection, refraction, diffraction and interference. They are characterized by speed of sound, sound pressure, sound intensity and they obey inverse square law when propagating from point source (Effion 1997).

Architectural acoustics is primarily aimed at enhancing speech and music clarity in enclosed spaces. Due to hearing complications arising from both the physiological and psychological peculiarities of individuals, it is necessary to incorporate environmental control factors like acoustics in building designs. This is most effective when done in the early stage of design as opposed to the post-construction phase, which is most prevalent today.

Aim:This report is to give an acoustic analysis of the ADVANCEMENT CENTRE

BUILIDNG, located at the Oba-nla staff quarters of the Federal University of Technology Akure, and to propose qualitative ways in achieving a better acoustics.

Objectives: To examine the existing acoustics conditions of the building in order to know if

there are adequate provisions for good acoustics. To analyze the common factors affecting the acoustics of the building both

internal and external sources and proffer solutions To examine the use of materials in effectively enhancing acoustics behaviour

within the building

Acoustics Analysis Of Advancement Centre Page 1

2.0 LITERATURE REVIEW

2.1 SOUNDSound is the energy produced by a vibrating object or surface and transmitted as a

wave through an elastic medium. Such a medium may be air (airborne sound) or solids. Sound is a disturbance or wave, which propagates through physical medium such as air or parts of the building structure in a longitudinal manner from the generating source to produce sensation of hearing at the receiving end. Sound waves exhibit reflection, refraction, diffraction and interference. They are characterized by speed of sound, sound pressure, sound intensity and they obey inverse square law when propagating from point source. Effions-Williams, (1997).

Sound is a physical phenomenon that stimulates the sense of hearing. In humans, hearing takes place whenever vibrations of frequencies from 15 hertz to about 20,000 hertz reach the inner ear. The hertz (Hz) is a unit of frequency equaling one vibration or cycle per second. Such vibrations reach the inner ear when they are transmitted through air. The speed of sound varies, but at sea level it travels through cool, dry air at about 1,190 km/h (740 mph). The term sound is sometimes restricted to such airborne vibrational waves. Sound has various properties amongst which are;

Amplitude: Amplitude is the characteristic of sound waves that we perceive as volume.

Frequency: We perceive frequency as “higher” or “lower” sounds. The frequency of a sound is the number of cycles, or oscillations, a sound wave completes in a given time. Frequency is measured in hertz, or cycles per second.

Pitch: Pitch is the property of sound that we perceive as highness and lowness.

Intensity: Sound intensities are measured in decibels (dB). Sound intensities are arranged on a logarithmic scale, which means that an increase of 10 dB corresponds to an increase in intensity by a factor of 10. The distance at which a sound can be heard depends on its intensity. Intensity is the average rate of flow of energy per unit area perpendicular to the direction of propagation. Intensity varies inversely as the square of the distance, provided there is no loss of energy due to viscosity, heat conduction, or other absorption effects.Sound Pressure:

McGuiness, et al. (1980) stated sound pressure to be a fluctuating pressure superimposed on the static atmospheric pressure in the presence of sound. Since audible sound consists of pressure waves. One of the ways to quantify sound is to state the amount of pressure variation s relative to atmospheric pressure caused as a result

Acoustic Analysis Of Advancement CentrePage 2

of sound generated. Pressure level can be evaluated by calculating the logarithmic value of the ratio of given pressure, P to standard threshold of hearing pressure.

Reverberation TimeReverberation time is the time for the sound to decay by 60dB (become

effectively inaudible) after the power source is shut off. Reverberation time = time to drop 60dB below original level (Hunt 1978). T = 0.3log10V, (3) where T is the optimum reverberation time in seconds, for speech and V is the

room volume in cubic meters (McGuinness, et al. 1980).

2.2 NOISENoise is any form of unwanted sound which is relative and subjective in nature.

(Harris, 1975) defines noise as a form of sound which is unwanted, annoying, interferes with speech and enough to damage hearing is called noise, while Salvato (1982) defines noise as ‘unwanted sound’.

2.3 ACOUSTICSThis is simply defined as the science of sound. This also includes the generation

of sound, the transmission and the effect of sound energy. Architectural acoustics deals with the provision of good condition for sound in buildings. This involves the design of building for good speech condition, privacy and freedom from distracting noise. Acoustics must also provide a good condition for listening. For the provision of good acoustics condition in a building, acoustical design involves controlling the amount of sound through absorption or sound insulation, blocking of sound and control of background noise.

The acoustical condition of a room is influenced by reverberation, background noise, loudness of the original sound, and the size and shape of the auditorium.

Acoustics of Internal SpaceAs regards the interior acoustics of a space, the volume of the enclosed area is

developed according to reverberation requirements of the shape. The shape of wall and ceiling surfaces is developed to give proper distribution of sound and eliminate focusing or echoes. Other factors to be considered include acoustic quality of finishes on walls, floors and ceilings, kind of fenestration, furniture surface available etc. (McGuiness, et al. 1980).


3.0 ANALAYSIS OF THE ADVANCEMENT CENTRE BUILDING

3.1 ARCHITECTURAL DETAILS/ BRIEF DESCRIPTION OF THE BUILDING

The Advancement Center is a 3-bedroom bungalow residential building converted to office use. The Advancement Centre is saddled with the responsibility of sourcing funds for the university. The Advancement Centre is located at the Obanla campus of the Federal University of Technology Akure. The building is bounded by other residential buildings at its East, Garage and Store to the West, Bounded by trees and vast land mass to the South, and North respectively, with access road to the North. Cars are being parked at the side and rear of the building.

The building is a 3-bedroom design bungalow designed to cater for the accommodation of staffs. It comprises of three bedrooms which has been converted to offices rooms, a living/ dining room, which is been converted to the reception, a kitchen and store, as well as conveniences. A square-shaped courtyard is also incorporated into the design to serve as the entrance patio as well as aid lighting and ventilation. The building is landscaped with trees and shrubs, and with a simple gabled roof at both ends.

3.2 FINISHES MATERIALS ANALYSIS OF THE BUILDINGThe following are the choice of finishes used in the construction of the various

components of the Advancement Building.

WALLS: 225mm X 225mm X 450mm hollow sandcrete block were used in constructing the walls, and are finished with emulsion paint on both the Interior and exterior. wet areas such as toilets, white ceramic glazed tiles were used as wall finish from the floor to the door height. Gloss paint was then used to complete the remaining surface area.

Plate 1: The internal Wall finished with cream emulsion paint.


CEILINGS: The ceiling is finished with the widely known of 1200mm x 1200mm asbestos ceiling boards painted with double coat of white emulsion paint and has a flat shape, which runs through the building to define the building’s headroom.

Plate 2: The asbestos ceiling Finish

FENESTRATIONS: All internal doors are timber paneled doors, while the main entrance door as well as the exit door from the kitchen are iron grill doors. Window openings are made of glass louver blade with wooden frame and nets.

Plate 3: showing window and door type

FLOOR: All floors were finished with ceramic glazed tiles of various sizes varying from 400mm x 400mm to 150mm x 150mm, at different spaces.


Plate 4: The ceramic tiles floor Finish. 3.3 THE PLAN OF THE FLOOR OF THE BUILDING SHOWING FURNITURE,

ARRANGEMENT AND FLOOR FINISHES.

Fig. 1: Floor plan of the building showing furniture arrangement and floor finishes


3.4 CEILING PLAN OF THE BUIILDING.

Fig. 2: Ceiling plan of the building. 3.5 SITE PLAN OF THE BUILDING

Fig 3: site plan showing the source of noise.


3.6 PICTURE SHOWING DIFFERENT VIEWS OF THE BUILDING.

Plate 5: showing different facades of the building

3.7 SOURCES OF NOISE TO THE ADCANCEMENT CENTRE Noise is usually defined as unwanted or damaging sound. There are several ways with which noise interferes with the on-going activities in the building. These would be discussed under two major headings namely:

Indoor noise. Outdoor noise.

3.8 SOURCES OF INDOOR NOISESThe major source of indoor noise in the building can be traced to the activities of the users themselves; activities such as verbal interactions with one another, movement from one place to another with different kind of foot-wears. In addition, electrical appliances like ceiling fans, air-conditioning and computer systems constitutes a noise problem in the building. The engines and rotating blades (especially in faulty fans) of ceiling fans and air conditions and the fans and clanking of the keyboard are some of the ways


through which these electrical appliances generate noise. It is pertinent to note that the level of noise generated by these appliances is sometimes disturbing or annoying

Plate 6: the ceiling fan used in the building

Plate 7: the interior furniture of the building (receptionist/ waiting area) Other sources of indoor noise include dragging of furniture on the floor, banging of doors, etc. These are categorized as impact sounds which at very high levels may cause hearing damage.

3.9 SOURCES OF OUTDOOR NOISESThough the Advancement Centre is located at the quiet zone, nonetheless, it ia still prone to noise from external source. Notable amongst the external source of noise is noise generated from vehicular and pedestrian movements on the access road, these activities could be in the form of engine noise, hooting of horns, or loud conversation of passers-by etc.


Plate 8: Access road; a source of outdoor noise

3.10 FACTORS AFFECTING THE ACOUSTICS OF THE ADVANCEMENT CENTRE.The factors that affect acoustics of any building include its size and shape, nature of materials and finishes, zoning etc. In attempting to analyse the acoustic performance of a building all these must be considered.

SIZE AND SHAPEThese greatly affect acoustic condition in a room and are the reasons for the definition of any acoustic condition. 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 Advancement Centre, the rectangular shape and not too large a size of the spaces in the building enhances good acoustic characteristic.FINISHESThe finishes used in the building can greatly affect its acoustic properties; thus, it is advisable to use sound absorbent materials as finishes. In the Advancement Centre, the choice of tiles as the floor finish poses an acoustic problem due to its hard, reflective surface as it increases the reverberation effect in the room, this does not favour the acoustic characteristic in the space. The wall finish used in the building is emulsion paint on rendered block wall. The block wall has a poor acoustic property. Cement plaster has a low absorption coefficient, 0.03 at 1000Hz. A soft porous covering is sometimes used 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. However, due to the small-sized nature of the spaces in this building, the acoustic importance of the ceiling is less important as compared with other finishes in the rooms.


It can be deduced from these points above that the major finishes used in the building does not help to attain an excellent acoustic performance considering the fact that its use as been changed from residential to office use, but the design, orientation and location of the building, to some extents has helped reduce the problem of noise.

4.0 ACOUSTICS IMPROVEMENT OF THE BUILDINGThe approaches to the improvement of the acoustic environment of the building can be highlighted under the two categories of noise sources i.e. outdoor and indoor noise. These suggested approaches are proffered in a bid to reduce noise levels to tolerable or barest minimum levels.

4.1 PROPOSAL FOR REDUCTION OF INDOOR NOISEThe following are the proposed ways in which indoor noise can be further reduced in the Advancement Centre building.

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 aggravated by multiple reflections from surfaces. The following available types of sound absorbers could be used:

1. Porous absorbents2. Membrane absorbents 3. Resonant absorbers4 .Perforated panel absorbents.

4.2 PROPOSAL FOR REDUCTION OF OUTDOOR NOISESuggested ways for further reduction of outdoor noise in the Advancement Centre building are:

ScreeningHigher shrubs can be planted along the access road to aid acoustic serenity which would further reduce noise from generated from the road users., as well as air borne noise.

InsulationThis can be useful in reducing the noise coming from the road. An insulating material can be embedded between the existing wall facing the road directly and a new one to be constructed directly behind it; the resulting insulated double skin wall offers a greater insulation from traffic noise. To make this approach more workable, the front door will have to be permanently closed or better still, changed to a double glazed aluminum framed door provided with door closers to ensure that it is closed after each use to disallow noise infiltration.


5.0 RECCOMMENDATIONIn order to improve the acoustic of this building there should be an improvement on the wall by using of the above mentioned sound proofing material

5.1 CONCLUSIONNoise control is a subject, which should be given prime consideration in any environment, whether academic, residential or administrative; most environments require a serenity to aid the concentration of the users. Beside the spatial requirements needed for the functionality of the building, 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.In addition, it should be noted that the acoustic management of a building is to be taken into consideration before the implementation of project since it is so costly to amend the construction after the building has been completed. If we discover that the acoustic effect of a building is not up to an appreciable level, the wall surface may be acoustically treated with sound-absorbing materials.Finally, an acoustic consultant should be employed both in new design and existing renovations of facilities. It is often observed that this aspect of the design is often neglected and it proves to be detrimental in the end because acoustic problems are generated at a later phase.

REFERENCES. Professor Olu OlaOgunsote. Acoustics and Noise Control Lecture notes Ivor H. Seeley,(1974); Building Technology, sound insulation pp 276.Effions-Williams J. (1997):McGraw Hill Encyclopedia of Science and Technology: Acoustical noise, pub McGraw Hill Book company 8th edition, vol. 1 pp. 76 – 87.www.sdngnet.comwww.google.ca/acoustic control_in public building.


http://www.google.ca/acoustic

http://www.sdngnet.com/

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· Web viewIntensity varies inversely as the square of the distance, provided there is no loss of energy due to viscosity, heat conduction, or other