INTRODUCTION

Architectural acoustics is a type of acoustic that study how to design a building and other spaces

that have pleasing sound quality and sound level. it include the design of concert hall, classroom

and even hearing system. 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. The acoustic of a building is determined by the reverberation level and time in

the spaces within the building. Reverberation is the persistence of sound in an enclosed space a

result of repeated reflection, scattering and resonations of air molecules.

This report is a study of TECHNOLOGY MUSEUM, located in the Federal University of

Technology Akure. It aims at examining the building’s acoustics conditions with a lucid

explanation of the effect of building’s size, its characteristic shape, and use of materials in

effectively enhancing speech clarity and combating noise problems in order to ensure satisfaction

for the users. In addition, noise problems, that were not sufficiently dealt with in the design stage

and others that have arisen over the years of occupation will be identified and solutions to

alleviate them will be proffered.

LOCATION

The Technology Museum is located at the Obanla campus of the Federal University of

Technology Akure The building is bounded by the Library Complex, Computer Resource Center

phase II, center for entrepreneurship and gender issues in science and technology CEGIST.

DESCRIPTION OF THE BUILDING

A museum is a "permanent institution in the service of society and of its development, open to

the public, which acquires, conserves, researches, communicates and exhibits the tangible and

intangible heritage of humanity and its environment, for the purposes of education, study, and

enjoyment

The TECHNOLOGY MUSEUM is one of the building or institution located in the Federal

University of Technology Campus, where objects of artistic, historical, and scientific importance

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and value are kept, studied and put on display, FUTA inventions are warehoused in the

Technology Museum.

FIG 01: SHOWING SITE PLAN

The Technology Museum under study located behind the school Library at Obanla campus of

the Federal University of Technology, Akure is a combination of regular rectangular shapes and

its elements of construction are:-

i. Sandcrete hollow block walls rendered with cement and sand mix, covered with paint.

ii. pivoted and fixed Aluminum window frame

iii. Wooden panel door for internal doors and iron doors for external doors

iv. Marble floor tiles

v. Poly vinyl chloride PVC ceiling sheets etc.

The building housed the exhibition hall and spaces, offices, conveniences and security stand. The

user of the building in one way or the other affect the acoustic properties of Technology Museum

with the noise they

generate.

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FIG 02: SHOWING FLOOR PLAN.

FIG 03: SHOWING CEILING PLAN

PLATE 01: SHOWING FRONT VIEW PLATE 02: SHOWING LEFT SIDE VIEW

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PLATE 03: SHOWING RIGHT SIDE VIEW PLATE 04: SHOWING REAR VIEW

ACOUSTIC ANALYSIS OF THE TECHNOLOGY MUSEUM

Noise is usually defined as unwanted or damaging sound. Numerous ways exist by which

noise interferes with the activities

External acoustic problem or Outdoor noise.

Internal acoustic problem or Indoor noise

The first stage of analysis is to identify the acoustic problems. The problems perceived are both

external and internal.

EXTERNAL ACOUSTIC PROBLEMS

Firstly, the location of the Technology Museum does not really affects its functions and

acoustical performance. Because it is situated in the quite zone of the university, The

Technology Museum is situated close to the school Library and other institution buildings where

noise generated from students and their Academic activities, teaching and non-teaching staffs

does not affect its functions due to the proper zoning of the building. The noticeable sources of

Noise produced are from

people footsteps which are mainly users of the building.

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vehicular activities from the flanking access road at the front of the building also serve as

a source of outdoor noise to the TECHOLOGY MUSEM building. These activities could

be in the form hooting of horns and engine noise.

The most pronounced source of noise to the building is the ongoing construction of the

school Library extension and the nearby iron benders or workers and carpentry workshop

located directly behind the building.

This affects the degree of speech audibility and cause a big concern to the Technology

Museum users. The diagram below emphasizes further.

FIG 04: SHOWING EXTERNAL NOISE SOURCE TO THE BUILDING

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PLATE 05: SHOWING LIBRARY EXTENSION UNDER CONSTRUCTION

PLATE 06: SHOWING IRON BENDERS AND CARPENTER WORKSHOPS

INTERNAL ACOUSTIC PROBLEMS

The shape, dimensions, construction and contents of any interior space would have effect on how

sound is transmitted, reflected, diffused and absorbed inside it. The Technology Museum

Building is the combination rectangular shapes that forms a polygon. It is about 23000mm

diameter.

Electrical appliances like ceiling fans, air-conditioning and computer systems, ringing

tones from mobile phones constitutes a noise problem in the building. The engines and

rotating blades 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.

Due to its use there is need for effective noise reduction and acoustical improvement.

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PLATE 07: SHOWING ELECTRICAL APPLIANCES PLATE 08: SHOWING ELECTRIC FAN

Other sources of indoor noise include footsteps, movement of furniture on the floor

Tiles, banging of doors, etc.

These are categorized as impact Sounds which at very high levels may cause hearing

damage.

FACTORS AFFECTING THE ACOUSTICS OF THE TECHNOLOGY MUSEUM

BUILDING

The factors that affect acoustics of a THE TECHNOLOGY MUSEUM BUILDING as an

institutional building include its size, shape nature of materials and finishes, etc. In attempting to

analyze the acoustic performance of a building all these must be considered.

SIZE AND SHAPE

These 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 Museum building,

the polygonal shape and recessed walls and size of the spaces in the building define an excellent

acoustic characteristic. Compared to the conventional rectangular shapes of rooms, the

characteristic shape of the spaces in Museum building enhances the acoustic condition. The size

of the spaces which are not as large as that of an halls makes the need for resolution of acoustic

problems minimal due to the fact that the problems are in fact, of a minimal nature. due to its

small size, problems of reverberation and echo are at a minimal or bearable level, though

noticeable.

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PLATE 09: SHOWING RECESSED WALLS AND SHAPE OF THE BUILDING

FINISHES

WALL

The building is made up of solid walls on its sides with a recess at regular intervals. This causes

sound reflection. Moreover, the thickness of the wall is 225mm which is hardly enough to stop

transmission. (Transmission could lead to leakage of confidential information). they were

rendered externally with texcote paint and internally with emulsion paint. In wet areas such as toilets,

decorative ceramic glazed tiles were used as wall finish from the floor to the door height. and also

ceramic tiles skirting are used in the interior spaces of the building. The block wall has a poor

acoustic property. Cement plaster has a low absorption coefficient. A soft porous covering is

sometimes used to aid absorption.

PLATE 10: SHOWING EXTERIOR WALL PAINT PLATE 11: SHOWING INTERIOR WALL PAINT

CEILING

Poly vinyl chloride PVC 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.

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PLATE 12: SHOWING PVC CEILING BOARD PLATE 13: SHOWING PVC CEILING BOARD

OF OFFICE OF EXHIBITION HALL

FENETRATION

All doors are timber-paneled doors, except the entrance and exit doors, which are iron grill

doors. Window openings are made of glass pivoted sash with aluminum frame. windows located

at the exterior walls of the building are wide enough for adequate lightning and ventilation, but

the doors and windows located at the side through which the room is accessed also allows in

noise from external sources such as passers-by and noise from the construction going on.

PLATE 14: SHOWING ALUMINUM WINDOW FRAME AND GLASS

FURNITURE AND FITTINGS: These are essentially the chairs, tables, ceiling fans,

fluorescent light tubes and fixtures, window blinds (fabrics) etc. These furniture and fittings have

effect on the acoustic behavior of the space. Singularly they not be a cause of disturbance but

their combine effect on speech coherence is obvious.

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PLATE 15: SHOWING FURNITURE IN OFFICE AND WINDOW BLIND

HEADROOM

The headroom of the exhibition hall is about 4.5m and that of the offices and other exhibition

spaces is about 3.0m. The headroom affects the reverberation time in that the higher the

headroom, the higher the reverberation time of sound. Reverberation is reduced in the offices as

compared with the exhibition hall due to the differences in the height of the headroom.

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PROPOSAL FOR IMPROVING THE ACOUSICS OF THE TECHOLOGY MUSEUM

BUILDING The 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.

PROPOSAL FOR REDUCTION OF INDOOR NOISE

The following are proposed ways in which indoor noise can be further reduced in the Museum

building.

Installation Of Carpet On The Floor

It is widely known that impact noise such as furniture movement, banging of doors, ringing tone

from mobile phone, from the keyboard and footsteps will be less in carpeted rooms as compared

to rooms with hard floor finish like floor tiles. Carpeting the floor reduces the Noise Reduction

Co-efficient (NRC). Carpets however have high maintenance costs, but this high cost could be

balanced with the acoustic benefits of sound absorbance.

Use Of Absorbent Screens And Surfaces

Absorptive materials used in architectural applications tend to fall into three categories: porous

absorbers, panel absorbers, and resonant absorbers. Of these, the porous absorbers are the most

frequently encountered and include fiberglass, mineral fiber products, fiberboard, pressed wood

shavings, cotton, felt, open-cell neoprene foam, carpet, sintered metal, and many other products.

Panel absorbers are nonporous lightweight sheets, solid or perforated, that have an air cavity

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behind them, which may be filled with an absorptive material such as fiberglass. Resonant

absorbers can be lightweight partitions vibrating at their mass-air-mass resonance or they can be

Helmholtz resonators or other similar enclosures, which absorb sound in the frequency range

around their resonant frequency. They also may be filled with 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: Porous absorbents

Membrane absorbents, Resonant absorbers Perforated panel absorbents.

Use of acoustic boards for the ceilings and moreover Flat ceilings distribute sounds

evenly

better than curved ceilings; flat ceilings should be made use of.

The use of texcote paint which makes the surfaces of the walls rough and help in

diffusing

sound better as against gloss and emulsion paint. The walls should be cover with acoustic boards

or timber panels

Circular columns can be used instead of octagonal columns, The columns can be cladded

with acoustic boards and timber panels .The edges of the beam and columns can be chamfered.

Reduce the centralized exhibition space to a particular area so that noise is mainly

generated

from that point.

Electrical Appliances ,The fans could be substituted with air-conditioners i.e. “Buy

Quiet” and Proper maintenance of equipment for their

PROPOSAL FOR REDUCTION OF OUTDOOR NOISE

Since majority of external noise is generated from traffic, pedestrians, and the motor park, which

cannot be eliminated, the following actions Suggested ways for further reduction of outdoor

noise THE TECHNOLOGY MUSEUM BUILDING are:

Screening

the noise coming from the building under construction and traffics can be screened off using a

fence or a buffer zone such as trees to aid acoustic serenity.

Insulation

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This can be used to reduce 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.

Buy Quiet Equipment And Machine in the nearby construction site to replace the

former one in use that generated greater noise to the building.

The Thickness Of The Glass can be doubled to reduce the amount of sound

transmitted into the building.

ASSESSMENT OF THE ACOUSTIC CHARACTERISTICS OF THE EXHIBITION HALL

IN THE TECHNOLOGY MUSEUM BUILDING WITH BACKGROUND NOISE,

REVERBERATION AND ECHO

BACKGROUND NOISE

The TECHNOLOGY MUSEUM BUILDING was not provided with most of the necessary acoustic

components from its design stage through construction to its occupation. This was supposed to

be achieved using design procedures rather than the use of construction materials and in any

case, sufficiently helped to reduce background noise to the barest minimum must be consider.

Background noise from activities of the Library extension under construction around and

adjoining facility as well as vehicular noise are properly shielded from the building.

REVERBERATION .

Reverberation – which is defined as the persistence of sound in an enclosed space as a result of

repeated reflection or scattering after the source had stopped. Highly reflective materials, such as

a concrete or tile floor, brick walls, and windows, will increase the reverberation. Absorptive

materials, such as curtains, cushioned furniture, heavy carpet, and people, reduce the

reverberation. Bigger rooms tend to have longer reverberation times. On the contrary,

reverberation in the TECHNOLOGY MUSEUM BUILDING is relatively small and

unnoticeable due to the small-sized nature of the rooms. Reverberation is quite evident in the

hall as a result of:

• Presence of series of sharp edges in the hall: The edges of beams, columns and furniture and

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recessed walls are sharp thereby increasing the effects of edge diffraction. Most of the edges

serve as

sources of noise which are later diffracted from there. This in turn pronounces the effects of

reverberation and causes more problems in the hall.

• Surfaces are smooth : The finishes on the wall, floors and ceilings are hard, smooth

and shiny. They tend to reflect sound easily and they have very low absorbing qualities. This

continuous reflection of sound from various sources cause increase in reverberation.

• Large curved ceiling in the central exhibition hall: The ceilings are the major sound surfaces in

the

exhibition hall because as the size of the room increases, so does the ceiling increases in

importance.

Since large curved surfaces tend to focus sound and create an uneven distribution of sound, the

high

curved ceiling in this hall also help in making reverberation in the hall quite evident.

ECHO: The spaces in the Museum building are not too large, hence echoes are not really

pronounced. These spaces however, do not experience this distinct repetition of sound. due to the

absorbent nature of the ceilings, etc. The floor tiles finish and the non-carpeted walls, many-

sided walls and the fenestrations however pose a problem as they increase the reflectivity of

sound in the space, thus aiding echo.

CONCLUSION

Controlling noise should be given prime consideration in academic and administrative

environment; most aspects of learning require a serene environment to aid the concentration of

the users. Aside the spatial requirements, 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.

Finally, an acoustic consultant should be included in new design of building and even in the

remodeling of old learning facilities to aid a suitable learning environment. In a bid to reduce

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construction cost, this aspect of the design is often neglected, and more often than not, it proves

to be detrimental in the end because acoustic problems are generated at a later phase.

REFERENCE

Professor Olu Ola Ogunsote.(c)2006/2007 Acoustics and Noise Control Lecture notes

Gary W Seiben, Martin A. Gold, Glenn W Seiben, Michael G. Ermann. (2000)Language

Speech and Hearing Services in the Schools. Vol.31. pp 376-384 Personal group field

research & case study.

Gary W Seiben, Martin A. Gold, Glenn W Seiben, Michael G. Ermann

(2000); Language Speech and Hearing Services in Schools. Vol.31. pp 376-384 Ivor H. See

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