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 ARCHITECTURE

IN 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 todays architectural environment, good acoustical design isnt a luxury its 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. Theres 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 Secretarys office, Assistant Coordinators office, Financial office, Lecture office, Staff Offices, Board room and conveniences.

Plate 1: Approach view of the building

Plate 2: Front ViewPlate 3: Right-Side View

Plate 5: Left-Side ViewPlate 6: Rear View

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

Plate 9: Interior view showing wooden doorPlate 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 Chancellors 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. Secretarys 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