Acoustical Analysis

ACOUSTICAL ANALYSIS

OF

THE FOUNDRY WORKSHOPBUILDING,

SCHOOL OF ENGINEERING AND ENGINEERING

TECHNOLOGY (SEET),

FEDERAL UNIVERSITY OF TECHNOLOGY AKURE,

ONDO STATE.

CARRIED OUT

BY

OLAJIDE FUNMINIYI DEZICK

ARC/09/7411

OKUNJOLU OLUWABUNMI ELIZABETH

ARC/09/7409

TO BE SUBMITTED TO THE DEPARTMENT OF ARCHITECTURE

IN PARTIAL FULFILMENT OF THE COURSE ENVIROMNMENTAL CONTROL III (ACOUSTIC AND NOISE CONTROL)

(ARC 507)

DATE:JUNE, 2014 LECTURER: PROF O. OGUNSOTE

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 ANALYSIS OF SOURCES OF NOISE

3.1 EXTERNAL SOURCE

3.2 THE INTERNAL SOURCE

4.0 PROPOSED WAY(S) OF IMPROVING THE ACOUSTIC OF THE FOUNDRY WORKSHOP.

4.1 INTERNAL NOISE

4.2 EXTERNAL NOISE

5.0 CONCLUSION

6.0 REFERENCES

1.0INTRODUCTION

Acoustics is the science of sound. It is primarily aimed at enhancing speech intelligibility and music clarity in an enclosed space.

Noise is one of the most common health hazards found in the workplace. Exposure to too much noise can cause noise induced hearing loss, which has been the most prevalent occupational disease for the past decades. Many countries have introduced legal obligations and guidelines requiring employers to protect their employees and others from exposure to excessive noise. These legal aspects set up the desired steps of a comprehensive prevention management system to achieve reduction in risk due to exposure to noise. This stand by several employers shows how imperative it is to know the acoustical state of any industrial workplace, therefore this paper has been prepared to assess and analyze the acoustical state of the foundry workshop, school of engineering and engineering technology, federal university of technology akure,ondo state.

2.0GENERAL DESCRIPTION OF THE WORKSHOP.

The workshop is rectangular in form. It is a singleand free standing building with no adjoining building or facility connected to it. It is located at obanla part of FUTA ,near the school library , engineering workshop and the academic building. The premise of the building is partially surrounded by shrubs and trees.

It possesses a special foundation (probably because of the potential vibration resulting from machines which the foundation will be subjected to).At the corners of the walls, instead of the usual reinforcement concrete column, used was a stanchioned steel bar connected to the foundation .The walls are made of hollow sandcrete block. The windows are small (600mm*600mm wide), the windows are glass louver blade windows andraised to a considerable height. It has three doors, the biggest serving as the main entrance while the remaining two serves as the exit doors, these doors are all made of steel. The roof of the building is made of steel as the roof trusses while the roofing sheet is made of long span aluminum roofing sheets.

Location map of the foundry workshop

Floor plan of the foundry workshop.

Approach elevation. Left-side elevation.

Rear elevation right-side elevation

2.1THE FLOOR FINISHES

The floor of the building is left unfinished. Floor screed is the only floor material that was used. This floor screed, generates lesser noise compare to when finishes like terrazzo are used.

Picture showing floor left bare, with the floor screed as the finishing.

2.2 THE WALL FINISHES

Wall surfaces affect the level at which sound is absorbed, transmitted and reflected.The walls are made of sandcrete hollow block and finished with emulsion paint.

Picture showing interior walls finished with emulsion paint.

2.3 THE CEILING FINISHES

There is no ceiling used, rather the roofing sheet and trusses serves as the ceiling.

More so the roof is constructed in a manner that will help to trap the noise being generated by the workshop. With the roof serving as the ceiling, reflection of sounds in the workshop has actually indirectly been enhanced through the design, which is not good enough. The steel trusses are prone to generating noise when subjected to vibration they should not have been exposed, acoustic materials could have been used to cover the trusses to reduce the level of reflection of sound.

Picture showing the interior of the workshop with no ceiling.

3.0 ANALYSIS OF SOURCES OF NOISE

The acoustic condition of the workshop is affected by various factors which range from external to internal factors i.e. noise is generated from both external and internal sources.

3.1 EXTERNAL SOURCE

External sources of noise include:

1. Noise generated from the car park which is located close to the workshop.

Picture showing parking spaces located at the front of the workshop which is a source of external noise generation.

1. Traffic from theadjoining road coming from the other part of the school also contributes as source of external noise.

1. Noises are also generated from adjoining buildings e.g. the academic building located close to the workshop.

Analysis of external noise

3.2 THE INTERNAL SOURCE

Major internal noise in the workshop arises from the machines and the handy tools during use.

Noise generating machines includes;

1. Generating plant: this is the alternative source of energy when there is no power supply from the power supply authority. It generates the highest level of noise in the workshop of about 70dB.the plant is placed in the workshop which makes its adverse effect more manifested.

Picture showing the generating plant

1. Pressure furnace: these are two in number, the first being the compression pressure furnace-which uses diesel for its fire supply- and the second is the gas pressure furnaceswhich produces fire for heating of moldingsby gas pumping with pressure to ensure continuous supply of the fire. Theyboth generate noise during operation by the fire, whenever it is burning ,which is usually with pressure. The noise generated by this furnace is around 40dB.

Compression pressure furnace. Gas pressure furnace.

1. Rotary furnace: This is the biggest of all the furnaces in the workshop. As a result, it generates more noise than the other furnaces. Its purpose like the other aforementioned ones is to produce an uninterrupted supply of fire for heating. During the process of fire supply or heating, a handful amount of noise around 56dB is generated.

Rotary furnace.

Other noise generating machines includes;

Polymer extractor

Grinding machines

Other noises are generated by hand-held tools like; hammers (generates noiseduring hammering), hacksaws (noise generated during cutting) and files (generates noise during filing)

Hammering. Cutting and filing.

3.0PROPOSED WAY(S) OF IMPROVING THE ACOUSTIC OF THE FOUNDRY WORKSHOP.

4.1 INTERNAL NOISE

The foundry workshop is an existing work place. Therefore noise control method of an existing workplace is best to be applied. The best method is hierarchy of control.

The hierarchy of control can be divided into:

Elimination:

Substitution

Isolation

Engineering control at source and in the transmission path.

Noise is a by-product produced during a transfer of energy, when some of the energy is not directly converted into useful work or into waste heat. The ways to control noise are:

reduce the amount of sound energy released;

divert the flow of the energy away from the receiver; or

Protect the receiver from this energy.

Elimination

Elimination is the first step that is usually considered when addressing exposure to noise at a workplace. After a critical examination of all existing processes it may be possible to eliminate the exposure entirely by changing one or more operations. For example, high quality welding eliminates or significantly reduces the need for grinding.

Substitution

This involves substituting quieter processes for noisy ones. A properly designed purchasing policy that incorporates the "buy quiet" concept is often the best and most cost-effective way of controlling noise exposure. It also minimizes the need for noise control later, which often can be very costly. A decision on the maximum acceptable noise emission levels from new equipment should be made before purchasing. This decision should take into account the organization’s noise policy and the existing noise levels in the area where equipment is to be placed.

Isolation

Isolation means separating noise sources from people involved in the work or others standing nearby. It could mean relocating the noise source or relocating the operators or others to positions away from the noise source. For example, by doubling the distance from the source inside a workshop the noise level decreases by about 2-4 dB (A), or in the open the noise level decreases by 6 dB (A).in the foundry workshop for example, thegenerating plant is installed inside the workshop. In cases like this the noise in the workshop can be reduced significantly by housing the plant outside the workshop.

Other methods include;

Administrative control is another method of noise control that as proved to be effective with little or no cost implications. It is any arrangement that significantly reduces the worker's exposure time to noise hazards, for example, job rotation, production scheduling, job redesign and introducing appropriate training on noise.

Provision of personal protectiveequipment:this involves the use of protective equipments such as earplugs or earmuffs. Itis usually treated as the last line of defenceagainst noise when noise and administrativecontrol measures are unable to keep the noiselevels below the criteria set for the workplace.

4.2 EXTERNAL NOISE

External noise of the foundry workshop can be reduced by;

1. Screening: this can be done by planting or installing trees, hedges and other barriers between the workshop and adjoining roads. These barrier(s) will then reflect any ensuing noise as a result of traffic.
2. Insulation: this involves the use and application of insulating materials on external walls so as to reduce the transmission through the walls into the workshop

5.0CONCLUSION

Every employee, student or researcher desires to have a good long lasting life and with all parts of their body (especially Ears) functioning well. Therefore, it becomes imperative to create or ensure a healthy environment for students, researchers and lecturers who work at or carry out experiment out at the foundry workshop.

Exposure to too much noise by anybody can lead to temporary or permanent hearing loss. So, analyzing acoustic situation of any building (especially workshops) becomes crucial. As an architect, acoustic of any facility should be considered important and monitored during design stages. Also clients should be advised by architect on the need and benefits of acoustic analysis of new and existing workplace since this can help boost the productivity of the workers.

6.0 REFERENCES

ProfessorOluOlaOgunsote.AcousticsandNoiseControlLecturenotes

GaryWSeiben,MartinA.Gold,GlennWSeiben,MichaelG.Ermann.(2000);LanguageSpeechandHearingServicesinSchools.Vol.31.pp376-384

IvorH.Seeley,(1974);BuildingTechnology,soundinsulationpp276.

