A REPORT ON THE ACOUSTIC ANALYSIS

Of

WEST AFRICAN SCIENCE SERVICE CENTRE FOR

CLIMATE CHANGE AND ADOPTED LAND USE (WASCAL

GPS-WACS) ADMINISTRATION BLOCK

Written and compiled by:

ONWUKA OKEZIE U. ARC/10/1165

OGUNSADE AYOOLA A. ARC/10/1140

Submitted to:

THE DEPARTMENT OF ARCHITECTUREIN PARTIAL FULFILMENT OF THE REQUIREMENT FOR THE AWARD OF

BACHELOR OF TECHNOLOGY (B TECH) IN ARCHITECTURE.

COURSE LECTURER:PROFESSOR O. O. OGUNSOTE

JULY 2014.

Table of Content.

1.0. Introduction.

2.0. General Overview of the Building

Location

Architectural Design

Materials Used

3.0 General Analysis of the Acoustics of the Building

4.0 Identification of Sources of Noise

External Noise

Internal Noise

5.0 Proposed Solutions towards improving the Acoustic Performance of the Building.

6.0 Conclusions

References

1.0 INTRODUCTION

Architectural acoustics is the process of managing how both airborne and impact sound is

transmitted and controlled within a building design. While virtually every material within a room

from furniture to floor coverings to computer screens affects sound levels to one degree or

another, wall partitions, ceiling systems and floor/ceiling assemblies are the primary elements

that designers use to control sound. Sound moves through building spaces in a variety of ways.

Most commonly, it is transmitted through air. But wall partitions, ceilings and floor/ceiling

assemblies can also transmit both airborne sound, such as human voices and ringing telephones,

and impact sound, such as footsteps on a floor. Sound waves actually travel through many

physical objects faster and with less loss of energy than they travel through air.

In today’s architectural environment, good acoustical design isn’t a luxury – it’s a necessity.

Acoustics impacts everything from employee productivity in office settings to performance

quality in auditoriums to the market value of apartments, condominiums and single-family

homes. While the science behind sound is well understood, using that science to create desired

acoustical performance within a specific building or room is complex. There’s no single

acoustical “solution” that can be universally applied to building design. Each built environment

offers its own unique set of acoustical parameters. Understanding these differences and knowing

how to utilize building materials, system design and technologies are key factors behind

successful acoustical design.

Technically speaking, sound is defined as a vibration in an elastic medium. An elastic medium is

any material (air, water, physical object, etc.) that has the ability to return to its normal state after

being deflected by an outside force such as a sound vibration. The more elastic a substance, the

better it is able to conduct sound waves. Sound vibrations travel through elastic mediums in the

form of small pressure changes alternating above and below the static (at rest) nature of the

conducting material.

When creating acoustical specifications, it is to be noted that every space presents a unique

acoustical challenge. An employment office, for example, may require all-confidential private

offices, while a bank may warrant varying levels of speech privacy. In office settings, conference

rooms and executive offices usually require high levels of acoustical control, but other areas may

require only moderate measures. Successful acoustical design is a detail-oriented process, both in

terms of specification and construction. Careful material and systems specifications are

imperative, as are good construction practices. Acoustical performance often depends not so

much on what was done correctly, but what was done incorrectly. The key to success is careful

attention to detail during all phases of planning, design and construction.

2.0 GENERAL OVERVIEW OF THE BUILDING

The building-in-view serves as a shelter for all administrative related activities for the WEST

AFRICAN SCIENCE SERVICE CENTRE FOR CLIMATE CHANGE AND ADOPTED

LAND USE (WASCAL GPS-WACS) as it encompasses the Director and Secretary’s office,

Assistant Coordinator’s office, Financial office, Lecture office, Staff Offices, Board room and

conveniences.

Plate 1: Approach view of the building

Plate 2: Front View Plate 3: Right-Side View

Plate 5: Left-Side View Plate 6: Rear View

Plate 7: Interior view (Reception) Plate 8: Interior view (Lobby)

Plate 9: Interior view showing wooden door Plate 10: Interior view showing metal door

Plate 11: Exterior view showing car park Plate 12: Exterior view showing the generator

LOCATION

The building is located along the road to the Vice Chancellor’s lodge, adjacent to the FUTA

Chapel and surrounded by staff quarters.

ARCHITECTURAL DESIGN

The design has a simple square plan with plain elevations for front, sides and back and the roof is

a simple symmetrical gable. The wall were plastered and finished with paint while the interior

spaces are partitioned basically with sandcrete blockwalls.

MATERIALS USED

The materials used for the construction are listed as follows:

Roofing: long span aluminum roofing sheets.

Walls: sandcrete blocks plastered with cement finished with emulsion paint.

Ceiling: the ceilings are asbestos ceiling boards and PVC ceiling boards for the internal spaces.

Doors: there are two materials used for the doors: wood and iron

Windows: the windows are double flush cascade windows.

Floor: the floor is finished with 300 X 300 tiles.

3.0 GENERAL ANAYLSIS OF THE ACOUSTICS OF THE BUILDING

The spaces that were accessed during the course of this analysis are of square and rectangular

forms. This, to an extent, enhance the acoustics of the spaces analyzed compared to spaces of

circular forms which are not present in the building according to the knowledge gained during

the class lecture for this course.

The materials utilized for the building shows that attention was not paid to the acoustic

performance of the building. The floor is finished with ceramic floor tiles, the seats are made of

stainless steel covered with either leather or cushion soft upholstery, the walls are painted with

emulsion paint, the ceiling is finished with PVC(Polyvinyl Chloride) ceiling finish for the

internal spaces and asbestos ceiling finish for the external ceilings.

The analysis of the building was carried out and the sound range was determined with the sound

meter in decibel (dB) at various accessible spaces in the building. The sound meter was used to

read the sound level of some possible accessed spaces within the building and also at some

selected external spaces around the building under normal day-to-day working condition. The

following values in decibel (dB) were recorded:

1. Entrance porch : 78 – 79dB

2. Reception : 78 – 80dB

3. Secretary’s office : 78 – 80dB

4. Lobby : 77dB

5. Toilet : 66 – 68dB

6. Car park : 78 – 81dB

7. Generator area : 83 – 85dB

Also during this survey, we were fortunate to witness how the acoustics of the building is under a

condition influenced by a natural phenomenon, rainfall. Using the sound meter, it was discovered

that the sound level of the building generally was increased by approximately 9dB.

It can be seen from the above that when the WASCAL GRP-WACS administrative building was

being constructed with little or no attention been paid to the acoustic performance of both the

interior and exterior parts of the building. Its acoustics was left to chance and was not well

planned to defeat acoustic problems.

4.0 IDENTIFICATION OF SOURCES OF NOISE

Noise, which is described as unwanted sounds, that affects the building-in-view can be

categorized into two, the interior and exterior noise.

Interior noise: Internal noise is noise coming from sources inside the building itself and these

sources include:

Conversations: This implies the sound produced from people conversing within the

building produces noise that is evenly spread.

Circulation: The movement of people within the building on the ceramic tile-finished

floor produces a lot of noise and contributes majorly to the noise affecting the building

especially when there are a lot of people moving around.

Air Conditioner: As mild as the air conditioner sounds in an enclosure, it cannot be

spared from being a source of noise. It also contributes to the acoustic disturbance

witnessed within the building.

Doors: The doors make some creaking sounds when opened and closed. This also

increases the noise in the building.

Office Machines: Office machines including photocopying machine, scanner and

computer among others make some individual noises that also majorly contribute to the

noise experienced in the building.

Water Dispenser: One of these units is placed at the reception for the use of visitors but

on its own produces a lot of noise.

External Noise: External noise is noise coming into the building from sources outside and

around the building in study, these sources are:

The Road: The building is located approximately 12m away from the road which serves

as access to the building. The movement of vehicles on the tarred road produces a lot of

noise considering the fact that it is the main access to the site. This represents the highest

contributor of external noise.

Pedestrians: The people moving on the walkways around the building produce noise from

their shoes and also their conversation along the way.

Car Park: The major car park for the building is located right in front of the building less

than 10m away. The movement of cars as well as people at the car park produces noise

within the building.

A/C Compartments: The air conditioning compartments outside the building produces

noises that also contribute to the noise experienced in the building.

Generator: The main generator that serves as alternative to public electricity supply is

located approximately 6m to the building with no sound shield whatsoever. When in use,

it produces a lot of noise that affect the acoustics of the building.

5.0 PROPOSED SOLUTIONS TOWARDS IMPROVING THE ACOUSTIC

PERFORMANCE OF THE BUILDING.

Improving the acoustics of the building-in-view can be done through identifying the various

sources of noise and then decide on action to take with them either by eliminating them,

modifying their transmission path, or reducing the level of their effect on the building to improve

the acoustics.

Eliminating known noise sources: The source of noise which can be eliminated includes

the noise from the road. The cars moving at higher speeds produce noise more than those

moving at lower speeds therefore more speed bumps should be provided to run through

the front of the building so that cars passing would be forced to slow down.

The air conditioners that are not working as expected should be serviced to reduce the

amount of noise coming from them and the broken down ones could be replaced using

the ‘buy quiet’ approach where the latest and more improved one are bought with less

consideration on their cost.

The doors that creak so much should be checked so as to tighten loose bolts and nuts,

lubricate joints and missing parts replaced with new ones.

The tile-finished floors which make a lot of noise when walking on should be overlaid

with wooden floor boards to absorb the sounds from individual shoes.

On the external and internal walls, the present emulsion finish should be replaced with

text coat to improve its ability to diffuse sounds. It could also be enhanced with the use of

wall carpeting.

More trees should also be planted to increase the ability of the environment to shield

away noises.

6.0 CONCLUSION

There is a need for a proper background in the study of acoustics for architects cannot be

overemphasized so as to improve the design of buildings that are acoustic friendly. The basic

acoustic considerations should be made and included in the design of the building before it is

constructed to avoid the problem of adjustments to standing structures.

There is also the need for the encouragement of the use of building materials and finishes that

enhances acoustics in buildings and also more researches should be carried out to ensure the

reduction in the noise level of basic office equipment and appliances.

REFERENCES

James D. Janning, AIA, CSI, Architectural Systems Manager, USG Corporation

Understanding Acoustics in Architectural Design

Ogunsote O. O. (Prof); Room and Auditorium Acoustics

Microsoft Encarta