SOUND INSULATION AND VIBRATION REDUCTION OF …eprints.uthm.edu.my/7548/1/MOHD_KHAIRI_BIN_MOHD_IMRAN.pdf · SOUND INSULATION AND VIBRATION REDUCTION OF MODIFIED ZINC ... 2.2 lists

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SOUND INSULATION AND VIBRATION REDUCTION OF MODIFIED ZINC

ROOF USING NATURAL FIBER ( ARENGA PINNATA )

MOHD KHAIRI BIN MOHD IMRAN

A thesis submitted in

fulfillment of the requirement for the award of the

Master’s of Mechanical Engineering with Honors

Faculty of Mechanical and Manufacturing Engineering

Universiti Tun Hussein Onn Malaysia

JANUARI 2015

6

CONTENTS

TITLE i

DECLARATION ii

DEDICATION iii

ABSTRACT iv

CONTENTS vi

LIST OF FIGURES x

LIST OF APPENDICES

xvi

CHAPTER I INTRODUCTION 1

1.1 Background 1

1.2 Significant of study 2

1.3 Research objective 2

1.4 Scope of study 3

1.5 Project planning 3

CHAPTER II LITERATURE REVIEW 4

2.1 Introduction 4

2.2 Sound absorption 4

2.3 Absorptive materials 7

7

2.4 Particulate reinforced polymer matrix composite 8

2.4.1 Corn cob 8

2.4.2 Pine sawdust 9

2.4.3 Rice-husk 10

2.5 Arenga Pinnata fiber 11

2.5.1 Fiber tensile properties 13

2.6 Roof system 15

2.6.1 Type of roof 15

2.6.2 Metal roof system 15

2.6.3 Metal roof system 18

CHAPTER III METHODOLOGY 19

3.1 Introduction 19

3.2 Material preparation 20

3.3 Roof sample construction 21

3.4 Testing apparatus 22

3.4.1 Impact hammer 22

3.4.2 Accelerometer 23

3.4.3 Sound receiver 24

3.5 Rain Simulator 26

3.6 Rain gauge measurement 27

3.7 Vibration testing 29

3.8 Noise measurement 31

CHAPTER IV DATA ANALYSIS AND DISCUSSION 32

4.1 Introduction 32

4.2 Result and comparison of vibration data for testing A 33

8

4.2.1 Impact at position 1.0 33






4.2.7 Impact at position 1 45







4.3 Result and comparison of vibration data for testing B 59












9



4.4 Result and comparison of sound data for all samples 85

4.4.1 Basic zinc and painted zinc (testing A) 85

4.4.2 Modified zinc A, B and C (testing B) 87

4.5 Result for precipitation rate by rain simulator 89

4.6 Discussion 90

4.6.1 Vibration test 90

4.6.2 Noise testing 91

4.6.3 Rain simulator 93

CHAPTER V CONCLUSION 94

5.1 Conclusion 94

5.2 Recommendation for future studies 95

REFERENCES 96

APPENDIX 97

10

LIST OF FIGURE

2.1 Room With and Without Sound Absorptive Treatment 5

2.2 Effect of sound absorbers addition 6

2.3 Absorption coefficients of composite materials M1 and M2 9

2.4 Comparison between 25 percents of rice husk 10

with the virgin polyurethane

2.5 Bundle of sugar palm fibers 11

2.6 Images of the surface of sugar palm 13

2.7 Construction of the vegetated roof (VEG) and experimental approach 14

2.8 Metal roof design 16

3.1 Bundle of Arenga Pinnata fibers 20

3.2 Basic zinc roof sample 21

3.3 Paint layered zinc roof sample 21

3.4 Sandwich roof type sample with arenga pinnata in between of zinc. 22

3.5 Impact hammer 23

3.6 Accelerometer 24

3.7 Sound reciever 25

3.8 Rain simulator 26

3.9 The sequel for rain gauge setup 28

11

3.10 Sketch and measurement on zinc roof sample 29

3.11 3 sample of zinc roof 30

3.12 Impulse hammer analysis system 31

4.1 Graph for basic zinc and painted zinc on position 1.0 33






4.7 Graph for basic zinc and painted zinc on position 1 45







4.14 Graph for modified zinc A (a) and modified zinc B (b) on position 1.0 59

4.14 Graph for modified zinc C (c) on position 1.0 60








12




4.20 Graph for modified zinc A (a) and modified zinc B (b) on position 1 71

4.20 Graph for modified zinc C (c) on position 1 72













4.27 Mean graph sound pressure level for basic zinc (a) 85

4.28 Mean graph sound pressure level for painted zinc (b) 86

4.29 Mean graph sound pressure level for modified zinc A (a) 87

and modified zinc B (b)

4.30 Mean graph sound pressure level for modified zinc C (c) 88

4.31 The result for precipitation rate produced by rain simulator 89

4.32 Graph vibration mean value (g*g) versus sound level (dB) 90

13

LIST OF TABLE

2.1 Material and structure for noise control 7

2.2 lists the utilization of sugar palm 12

2.3 Correlation between annoyance and noise disturbance (Side effects) 15

3.1 Microphone specification 25

3.2 Rain simulator equipment 26

4.1 Data for basic and painted zinc on position 1.0 34






4.7 Data for basic and painted zinc on position 1 46







14

4.14 Peak data for position 1.0 60






4.20 Peak data for position 1 72







4.27 Mean graph vibration for basic, painted and modified zinc 90

4.28 Mean graph vibration for modified zinc A, B and C 90

4.29 Mean graph sound pressure level for basic and painted zinc 91

4.30 Mean graph sound pressure level for modified zinc A, B and C 91

15

LIST OF APPENDICES

A1 Master Project 1 Gantt Chart 98

A2 Master Project 2 Gantt Chart 99

B Calculation

100

C Precipitation Graph

101

16

CHAPTER 1

INTRODUCTION

1.1 Background

Nowadays, due to technology development and environmental situation, noise and

vibration have become a serious environmental problem. Demand on the sound

absorptive materials increased consistently to the industrial development. There are

varieties of materials that used for sound absorption materials, affordability, low rate

of CO2 emissions to the atmosphere, and small energy and water consumptions are

some of the parameters that have to be taken into consideration when a product is

designed. Using green building materials which are renewable, local and abundant is

a solution that contributes to achieve these important goals. The types of green

materials that usually have been used such as bagasse, cereal, straw, corn stalk, corn

cob, cotton stalks, kenaf, rice husks, rice, straw, sunflower hulls and stalks, banana

stalks, coconut coir, bamboo, durian peel, oil palm leaves were amongst products

that can be processed as particleboard, hardboard and fiber board, and focusing on

their thermal insulation ability.

Rain is the most common nature that occurs in Malaysia. . The conventional

metal roof does not have any insulation properties layer to provide good noise and

vibration insulation from the impact of rain. Most of the houses used asbestos board

for ceiling and there is no solid medium between the ceiling and the roof to provide

the noise and vibration insulation. New idea was proposed to design a new solution

for this matter especially to low cost housing areas that used metal roof because it is

cheap compared to brick roof. Metal type roof has very high percentage to rain

noise and vibration exposure. Noise and vibration exposure make the residents feel

17

uncomfortable. Educational institutions, commercial buildings, theatres and stadium

which utilizes metal roofing faced the same problem of rain impact noise and

vibration especially during heavy downfall. When it rains, the raindrops excite the

metal roof panels through random impact force and as a result, the metal panels

resonate and generate high level of noise and vibration, especially during heavy

downpour.

1.2 Significance of Study

This project is to study on the ability of Arenga Pinnata (also known as Ijuk fiber)

as noise and vibration isolator and to find a suitable method as solution to implement

the properties onto the metal roof. This research focuses on suitable design of the

noise and vibration isolator to reduce the noise and vibration at the zinc roof and by

working with this natural fiber could give benefits to our environmental issue and at

the same time hopefully will reduce the cost.

1.3 Research objective

The aim of this research is to investigate the feasibility of Arenga Pinnata (Ijuk)

fiber to be employed as acoustical layer of component. To achieve this aim, several

objectives have been described as follows:

i. To propose the suitable design for the zinc roof that is capable to isolate

noise and vibration using layers of Arenga Pinnata fibers.

ii. To determine suitable vibration absorber using Arenga Pinnata fiber with

zinc roof that can reduce transmitted vibration and noise levels.

1.4 Scope of study

i. Study on the effects of noise and vibration when the Arenga Pinnata

fiber materials sandwich between the zinc roof without paint or

other mixture.

ii. Study about the roof zinc that can facilitate this research.

18

iii. Identify the reduction of noise and vibration using pure Arenga

Pinnata.

iv. Compare the values on noise emission and vibration distribution

between modified zinc roof and standard zinc roof.

1.5 Project Planning

The study on first semester will cover the introduction of reserach work, literature

review and methodology. The second semester will involve by comeout with suitable

roof desgin, testing, and collecting data reading. This include the analysis, discussion

and result and also suggestion for future work.

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CHAPTER 2

LITERATURE REVIEW

2.1 Introduction

Sound is a form of energy that is transmitted by pressure of air in variations which

the human ear can detect. Sound able to travel through other substances, such as

water or steel. Sound which is not desired is called noise. It is unwanted sound.

Noise may consist of a single pure tone but most cases contain many tones at

different frequencies and intensities. The sources of noise come from industrial

sectors, transportation, construction, building services, domestics’ noise and noise

from leisure activities. Noise may give serious problem on human but it depends on

the frequency exposed to determine its effect. Sound is “absorbed” by energy

conversion into heat in the material. Conventional materials such as glass fibers,

open cell foams, and acoustic tiles are often used as the sound absorbent materials.

These materials are called dissipative or porous materials due to the sound energy

that are dissipated in the interstices of the fibers. Their maximum efficiency occurs at

the typical thickness of these materials.

2.2 Sound Absorption

Sound absorption is defined as incident sound when the wavelength of sound waves

that strikes on a surface is smaller than dimensions of the materials surface. Sound

energy is dissipated into small number of heat as waves bounce around within the

material.

20

In large auditorium, the echo in audience areas near to the stage can be optimally

reduced by adding sound absorption material at rear and sides. When a sound source

is enclosed in a room, the level of sound inside the room is changed. The level of the

sound (reinforcement of sound) depends on how much the surfaces of the room

absorb (or reflect) sound shown in figure 2.1. The level of the sound (reinforcement

of sound) depends on how much the surfaces changed. When a sound wave strikes

one of the surfaces of a room, some of the sound energy is reflected back into the

room and some penetrates the surface. Parts of the sound wave energy are absorbed

by conversion to heat energy in the material, while the rest is transmitted through.

The level of energy converted to heat energy depends on the sound absorbing

properties of the material. A material's sound absorbing properties are expressed by

the sound absorption coefficient, α, (alpha), as a function of the frequency. α ranges

from 0 (total reflection) to 1.00 (total absorption).

As seen in the figure 2.2, the addition of sound absorption to the ceiling of a

small room (<46.45m2) can reduce the 10 dB reverberant sound levels of noise

source. If all wall and ceiling are treated with sound absorbing material, the sound

level in the reverberant field drops an additional 6 dB. Each doubling sound

absorbing material within the room reduces one half reverberation times. On the

other hand, there is no effect for sound level that close to sound source. Absorption

treatment closing to the sound source will only reduce 3 dB of noise source. Walls

covered with sound absorbing materials do not have the ability to reduce noise from

Figure 2.1 : Room With and Without Sound Absorptive Treatment.

(Egan, 1988)

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a source. The maximum effect possible in covering walls with absorbing materials is

to avoid reflected noise (Egan, 1988).

The description and comparison of different type of acoustical materials, like and

absorptive barrier materials, silencers, damping treatments and vibration isolators are

summarized in Table 2.1. The first three categories function is to absorb or attenuate

airborne sound waves. In other words, some vibrating object in contact with a

medium has created sound waves whose propagation through the medium is to be

minimized. The last category function, vibration isolation is to minimize the

transmission of shaking forces into a floor or other solid structure. This force, if not

attenuated, can cause vibration of the structure and consequent widespread

generation of sound waves. The fourth category function– damping treatments - is to

reduce the amplitudes of resonant vibrations that generate airborne sound and or to

minimize the transfer of vibratory energy at panel edges or attachment points to

adjoining structural elements.

Figure 2.2 : Effect of sound absorbers addition.

(Egan, 1988).

22

Category Description of Purpose of Representative

uses of

Absorptive

material

relatively

lightweight: porous,

with inter- connecting

passages;

poor barrier

Dissipation of

acoustic energy,

through

conversion to

minute amounts

of heats

Reduction of

reverberant sound

energy;

dissipation of

acoustic energy in

silencers.

Silencers

series of parallel

combination

of reactive elements

Dissipation of

acoustic energy

in

the presence of

steady flow

duct silencers

inlet exhaust

silencer for

engines, fans,

turbines.

Barrier

materials

Relatively dense,

nonporous

Attenuation of

acoustic energy

Containment of

sound

Damping

treatments

Viscoelastic materials

with

relatively internal

losses

Dissipation of

vibratory energy

Reduction of

acoustic energy

Vibration

isolator

Resilient pads,

metallic springs

Reduction of

transmitted

forces

Mounts for fans,

engines,

machinery

Table 2.1 : Material and structure for noise control

(Egan, 1988).

23

2.3 Absorptive materials

The function of absorptive materials is to transform acoustic energy into heat. The

two mechanisms by which energy is dissipated are viscous-flow losses and internal

friction. Viscous-flow losses are an effective absorber structure which consists of a

series of interconnected pores or voids where sound waves propagate into and

through the structure (Wassilieff C., 1995). Internal friction from some absorptive

materials have resilient fibrous or porous structures that are compressed or flexed by

sound wave propagation. In these structures, dissipation occurs not only from

viscous-flow losses but also from the internal friction of the material itself. The

absorptive characteristics of acoustical materials are determined by their pores or

voids size, interconnections between pores or voids, and material thickness (Ancuta,

B., 2011). The acoustical impedance at the materials surface and at various

frequencies and angles of incidence is probably the best descriptor of the relationship

between material properties and dissipation of acoustic energy.

2.4 Particulate reinforced polymer matrix composite

Polymer composites are an optional substance that basically has replaced

conventional engineering materials such as metals, plastics and ceramics in many

engineering applications lately. Nowadays, composite materials are chosen as

materials in engineering products for a variety of reasons and capabilities of new

product with desired properties including lightweight, high stiffness, high strength,

low thermal expansion, corrosion resistance and long fatigue life. Recently, natural

fiber composites are used in many non-structural and semi-structural applications

due to their low cost, renewable and abundance such as coconut fibers, oil palm

fibers, pineapple leaf fibers and wood fibers reinforced polymer composites.

Previous research (Faustino, J., 2012)on numerous work have been conducted in the

areas of natural fiber composites using different types of fibers from bamboo, oil

palm, rice-husk and wood (Mahzan, 2009).

24

2.4.1 Corn cob

Corn cob has an additional advantage in terms of possible application for alternative

processed products because it does not collide with the worldwide food stock and it

is generally considered as agricultural waste. Corn is mainly farm dominantly in

Portugal. Corn and corn stalk have different uses but the corn cob itself is treated as

agricultural waste which it is necessary to burn. It may fertilize the soil,

unfortunately, this option does not contribute to a better environmentally friendly

world. Corn cob particleboard has been under research in order to assess it as a

possible alternative sustainable solution for different building applications.

Previously, the microstructure and the elementary chemical composition of the corn

cob were identified by performing a scanning electron microscopy/energy dispersive

spectroscopy (SEM/EDS) analysis (Coutts, 2013). These results have inspired us to

think about a possible affordable and sustainable corn cob particleboard solution as

an alternative to the previously reported ones. Therefore, a simple manufacturing

process consisting in binding corn cob particles with wood glue according to the

ratio of 1:4 (glue: corn cob particles), in terms of weight, is proposed here.

2.4.2 Pine sawdust

Knowledge on acoustical materials is essential for the practicing noise control

engineer. Without this knowledge, cost effective control of noise become more a

matter of chance than of intelligent design. In this journal, (Ancuta, 2011) the author

described and compared different type of acoustical materials, such as absorptive

barrier materials, silencer, damping treatments and vibration isolators. The major

characteristics for each of these categories are summarized. The first categories

function is to absorb or attenuate airborne sound waves. Some of the vibrating object

that in contact with a medium has created sound waves whose propagation through

the medium is to be minimized. The next category function is vibration isolation that

is to minimize the transmission of shaking forces into a floor or other solid structure.

Based on this journal, they used pine sawdust with density, ρ = 0.035 g/cm3

to do the experiment on sound absorption coefficient on the material binded with a

commercial polyurethane binder PU 131. The two plate were made from pine

25

sawdust with different percentage of 20% (M1) and 30% (M2) binder (Ancuta,

2011).

Figure 2.3 : Absorption coefficients of composite materials M1 and M2

(Ancuta, 2011).

In Figure 2.3, the absorption coefficient for M1 and M2 in low frequency range is

low, but then at the frequency of 600 Hz the absorption coefficient begins to reach

values over 0.4. In high frequency range (630- 5000 Hz) the absorption coefficient

value increase with frequency which shows good sound absorbing properties. An

improvement of the absorption coefficient can be observed for material M2 over M1

on frequency ranges 125-1000 Hz and 1600-3150 Hz.

2.4.3 Rice-husk

Natural fiber for sound absorber material has caught lot of researchers lately due to

the whole world that encouraging people to run green technology. One of them is the

research on the use of rice-husk waste as the potential element for sound absorption

material of rice-husk reinforced composite. The rice husk is initially cleaned and

dried up at room temperature within 25 to 30 ºC[7]

. The dried rice husk was then

mixed together with Polyurethane (PU) foam as a binder to produce the rice husk

reinforced composite. Six different samples have been produced according to the

percentage of rice husk. The specimens were tested using an impedance tube. The

result showed that the best percentage of rice husk was obtained at 25 percents. The

sound absorption coefficient obtained demonstrated that the mixture produced the

best performance at low frequency region. The results also demonstrated that the rice

26

husk reinforced composite have a better sound coefficient compared to other natural

materials, hence promising a great potential for commercialization.

Figure 2.4 : Comparison between 25 percents of rice husk with the virgin

polyurethane.

Figure 2.4 demonstrates the comparison between the virgin PU and the 25 percent of

rice husk added with PU. The result shows that the patterns of both curves were

different. At low frequency, 0 – 500Hz, sound absorption of rice husk was higher

than virgin PU with the value of 0.899 at 250Hz. whereas, the virgin PU recorded

higher absorption at a higher frequency, 2000Hz with a value of 0.679.

2.5 Arenga Pinnata fiber

Arenga Pinnata fiber, known as Ijuk, is the fibers produced from sugar palm. Sugar

palm is one of the oldest cultivated plants in Asia. Geographically, it distributed in

all of tropical South and Southeast Asia countries, from India to Guam and from

Myanmar to Nusa Tenggara Timur in Indonesia. Typically, it grows close to human

settlements where anthropochoric breeding plays a major role. It is a fast growing

palm that reaches maturity within 10 years.

27

It has become an enduring match throughout the world and a most economically

important plant in Asia. Sugar palm is one of the most diverse multipurpose tree

species in culture. Almost of all parts of the tree is daily utilized shown in Table 2.2,

since the last decade (Mogea, 1991).

Sugar palm fibers has a great versatility in many application, that makes it one of the

oldest cultivated plants (Mogea, 1991). It is used for construction materials, sugar,

sago, wine, alcohol, fiber, thatch and many other products. This plant exhibits the tall

palm with long leaves and decorative trunk fiber. The plantations of sugar palm plant

have not been fully developed yet. However, recent development shows there is a

new way to cultivation the sugar palm plant effectively. The first sugar palm factory

has been built in Tomohan, Indonesia and there is availability of sugar palm fibers as

by-product.

Figure 2.5 : Bundle of sugar palm fibers

28

2.5.1 Fiber tensile properties

Based on the research by this author, the performance of sugar palm fiber with other

natural fibers shows that the tensile strength of sugar palm has moderate value and

almost the same with the strength of coir, kenaf, bamboo and hemp fibers (in the

range of 138.7 – 270 MPa) (Mogea, 1991). Based on the result, there is a possibility

of using sugar palm fiber as reinforcement for polymer composites.

Part of sugar palm Utilization

Root

Tea to bladder, insect repellent, post for

pepper, boards, tools handle, water pipes,

musical instruments

Steam core Sago, fibers

Pitch of leaf's rachis Drinking cup

Young leaves Cigarette pepper, salads

Leaflets midrid Brooms, baskets

Fruit Sap tapped for fresh drink, wine, vinegar,

palm sugar

Endspore, of unripe Cocktail

Flower Source of nectar honey production

Old woody leaf bases Biofuel

Timber The very hard outer part of the trunk is used

for barrel, flooring and furniture

Hair of base of the ;leaf

Sheaths Fire ignition

Table 2.2 : Lists of the utilization of sugar palm.

(Mogea, 1991)

29

Natural

fibre

Density

gr./cm

Tensile

strength,

Mpa

Tensile

modulus, Gpa

Strain, % Diameter,

µm

Sugar

palm

1.29 190 3.69 19.6 99-311

Curaua 1.33 655-1404 20.36 3-Feb 49-100

Nettle 1.53 1594 87 2.11 19.9

Hemp 1.48 270 19.1 0.8 31.2

Hemp 1.48 550-900 73 1.6

Jute 1.14 393-773 26.5 1.8

Coir 1.25 138.7 6 10.5 200

Kenaf 1.4 215.4 13-17 1.18-1.31 396.98

Bamboo 0.6-0.8 200.5 10.2

E-Glass 2.55 1800-3000 72-83 3 14

The modulus behaviour of sugar palm fiber gave the lowest value compared to other

fibers shown in Table 2.3 and it indicates the level of stiffness of the fibers. In

addition, the strain of sugar palm fiber gave the highest value compared to others.

From this, it is noticed that sugar palm fiber is more flexible than the other natural

fibers.

The thermal degradation of these components were found in ranges of 45–123, 210–

300, 300–400, 160–900 and 1723°C, respectively. Thermogravimetric analysis and

derivative thermogravimetric analysis curves showed that the fiber of 1m showed

higher thermal stability than the fibers of 3–15m (Ishak, 2012). The different thermal

stability for each fiber was due to different chemical compositions especially when

the fiber containing high ash content which result in higher thermal stability.

Table 2.3 : The mechanical and physical properties of sugar palm fibre.

http://www.researchgate.net/researcher/2006492805_U_M_K_Anwar/

30

2.6 Roof system

A roof is the essential part of a building which covers the uppermost part of

a building or acts as shelter. The purpose is to provide protection from rain which is

unexpected in Malaysia, but also from heat, wind and sunlight (Tukimat, 2011).

The basic shapes of roofs are flat, skillion, gabled, hipped, arched and domed. There

are many variations on these type (Harris, “Dictionary of Architecture &

Construction”.Roofs) constructed from flat sections that are sloped are referred to

aspitched roofs (generally if the angle exceeds 10 degrees). (Ferreira, 2012) Pitched

roofs, including gabled, hipped and skillion roofs, make up the greatest number of

domestic roofs. Some roofs follow organic shapes, either by architectural design or

because a flexible material such as thatch has been used in the construction.

2.6.1 Type of roof

Previous research from this author (Coutts, 2013) shows that they come out with

green effort, the green and cool roofs that are commonly to provide urban heat

mitigation potential; however, their performance is highly dependent upon their

design, particularly green roofs that vary in substrate depth, vegetation species, and

watering regime. This study compares the insulating properties, including a green

roof (extensive green roof planted with Sedum) and a cool roof (uninsulated rooftop

coated with white elastomeric paint)[1]

. They also used other alternative such as

corncob as a particleboard. Figure 2.7 shows a VEG consisted of a plywood base,

steel sheet, black poly membrane, plastic ‘egg cup’ sheet, geotextile layer and a

scoria-soil mixture. The vegetation type was Sedum rubrotinctum. The measured

Figure 2.6 : Images of the surface of sugar palm

http://en.wikipedia.org/wiki/Building_envelope

http://en.wikipedia.org/wiki/Building

http://en.wikipedia.org/wiki/Shelter_(building)

http://en.wikipedia.org/wiki/Rain

http://en.wikipedia.org/wiki/Heat

http://en.wikipedia.org/wiki/Wind

http://en.wikipedia.org/wiki/Sunlight

http://en.wikipedia.org/wiki/Flat_roof

http://en.wikipedia.org/wiki/Skillion_roof

http://en.wikipedia.org/wiki/Gable

http://en.wikipedia.org/wiki/Hip_roof

http://en.wikipedia.org/wiki/Arch

http://en.wikipedia.org/wiki/Dome

http://en.wikipedia.org/wiki/Pitched_roof

31

daytime energy balance is represented schematically (left) along with the measured

soiland cavity variables (right).

The purpose of the research is to be affordable and sustainable. So far, some

of its assessed material properties (e.g. density, fire resistance, durability, thermal

conductivity, compression and bending strengths, and impact resistance) suggest

adequacy of this product for several building applications, such as a thermal

insulation product, a light weight partition wall, a ceiling coating, or as indoor doors,

among other possibilities (Faustino, J., Pereira, L., Soares, 2012). The researchers

from China found other solution by using a mixture of 70% metakaolin and 30%

blast furnace slag powders is used as the raw material in the production of inorganic

polymeric foams (IPF) with various densities ranging from 0.4 to 1.0 g/cm3 and

different thicknesses of 6, 10 and 14 cm using a mechanical foaming method. The

water absorptions, sound absorption coefficients and sound transmission losses of the

IPF specimens were measured and then compared with each other to evaluate the

effects of their density and thickness (Wang, 2013)

There are previous research working on roof tiles for clay and concrete roof tiles

(Huang, 2009). These roof been tested using wall of wind to determined performance

of the roof under hurricane impact. Three different attachments were used for clay

and concrete roof tiles: adhesive-set foam, mortar-set, and mechanical fasteners.

Some are using two types of roofing materials, which is non-porous and porous

potential. The study to determine which ones might best be used to create a more

effective system by utilizing their moisture absorption and evaporation capabilities.

Figure 2.7 : Construction of the vegetated roof (VEG) and experimental approach.

32

The measurement results showed that porous materials can satisfactorily lower

surface temperature. The better performance of large size particles could possibly be

caused by the ventilation occurring within the material layers and high solar

penetration through the large gaps between particles, which would release more

latent heat when compared to materials of smaller particle size. Finally, analysis of

surface energy balance suggested that water contents, solar absorptivity, and wind

effects all have significant influences on cooling the surface temperature (Nagano,

2007).

2.6.2 Metal roof system

It is well-known that metal deck roof system is very popular by most medium

income residents in Malaysia (Ishak, 2012), other than that it provides a lot of

benefits compared to other roof systems such as their aesthetic value, less

maintenance, variability in design, durable, and lightweight. Indeed, many

developing countries like Malaysia, their buildings adopting metal roof system in

their current building design such as public buildings, university building and not to

mention mostly been adopted in most villages house. However, in terms of acoustic

performances on metal roof system is still lacking. In fact, it is forming from thin

sheet of steel cladding. Even, multiple layers of insulation laid within the roof

system, sound from impact noise especially rain noise amplified the metal and causes

unpleasant sound in a building (Choi, 2004). Sound from impact noise creates

vibration that causes structure-borne sound imparted directly to the building

structure. This transmission usually generates unwanted sound whereas ambient

noise in a building would increase.

Figure 2.8 : Metal roof design

33

Acoustic transmission in building design refers to a number of processes by which

sound can be transferred from one part of a building to another. The acoustic

performances on metal roof system are still lacking. The ambient noise is a combine

noises which emanates from various sources that can cause distraction or a nuisance

to the occupants shown in table 2.4.

Apart from that, these distractions may affect the level of occupants’ comfort in a

building such as annoyance, dissatisfaction and disturbance (Masamitsu, 2008) In

other words, occupants deserve to obtain a comfortable condition to generate well

being and valuable quality in their life. Thus, this paper aims to substantiate the

relationship between annoyance and noise disturbance in terms of activities and side

effects caused by rain noise.

Response on noise

disturbance (side

effect)

Correlation

Coefficient

values

Relationship

p<0.01 and p<0.05

Annoyance in

relation to unfocused 0.0701 0.01

Annoyance in relation

to stress 0.641 0.01


to communication

problem

0.715 0.01


to sleep disturbance 0.312 0.01


to health effect 0.166 0.05

Table 2.4 : Correlation between annoyance and noise disturbance (Side effects).

(Idris, Occupant’s responses 2012)

34

CHAPTER 3

METHODOLOGY

3.1 Introduction

This chapter discussed about how this study conducted to achieve its objectives. In

every study or experiment, the methodology used is crucial as sometime it will affect

the results of the experiment. So, the right choice of methodology is important for

every study including this one.

In this experiment, the fabrication of sample, the dimensions of the test roof, testing

apparatus, fabrication of testing apparatus and data interpretation was done

specifically to make sure the objective of our research achieved.

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3.2 Material preparation

Arenga Pinnata fibers refer to Figure 3.1 will be used as a raw material for acoustical

element. Initially, the fibers are cleaned and washed with distilled water .

In the making of acoustical panel, sugar palm fibers are cut into 44.5cm same length

as the zinc roof sample, used as the layer between the roof panel.

3.3 Roof sample construction

There are two separate testing which are categorized as Test A and Test B. Where

the Test A consist of two samples which are basic zinc and painted zinc. While for

Test B covers three samples consist of modified zinc A, B and C. For started, a

0.5mm thickness of conventional zinc roof is cut into a measurement of 44.5cm x

41.5cm for each four samples of roof.

Figure 3.1 : Bundle of Arenga Pinnata fibers.

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3.3.1 Samples Test A

(a) (b)

Figure 3.2 : Basic zinc roof sample.

(a) (b)

Figure 3.3 : Painted layer zinc roof sample.

Figure 3.2 shows a zinc roof without any insulation which is represent as basic zinc,

while figure 3.3 shows the second sample zinc roof painted with oil paint on the top

of it which is represent as painted zinc.

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3.3.2 Samples Test B

(a) (b)

(c) (d)

Figure 3.4: Arrangement fibers sandwich design roof (d) for sample modified zinc A

(a), modifies zinc B (b) and modified zinc C.

Each sample in Test B in sandwich roof type form as shown in Figure 3.4 (d) and the

variables is the arrangement of the fiber. Figure 3.4 (a) shows sample for modified

zinc A and the arrangement for it fiber in x-axis same direction the arrows is point at,

while Figure 3.4 (b) shows sample for modified zinc B and the arrangement for it

fiber is in y-axis same direction as the arrows is shown in the figure. In the other

hand for modified zinc C, the fiber arrangement in two axis which are y-axis and x-

axis. Since the experiment is to be held with natural fiber and green environmental

friendly, the sample do not mixed with other adhesive or binder.

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3.4 Testing Apparatus

The experiments will be conducted in Vibration Laboratory, Universiti Tun Hussien

Malaysia (UTHM). All equipments that used in this project are to measure vibration

testing, noise exposure and rain simulation’s precipitation. The functions of these

equipments is described at below;

3.4.1 Impact Hammer

Figure 3.5: Impact Hammer

The dynamic response of a mechanical structure while either in a development phase

or an actual use environment can readily be determined by impulse force testing.

Using an FFT analyzer, the transfer function of the structure can be determined from

a force pulse generated by the impact of a hammer and the response signal measured

with an accelerometer. The impulse force test method, yields extensive information

about the frequency and attenuation behavior of the system under test.

The stainless steel head of an impulse force hammer is equipped with quartz,

a low impedance force sensor which accepts impact tips varying in hardness. A

selection of steel, plastic, PVC and rubber tips along with an extender mass allow the

hammer to be tailored to impart to the test structure, a desired spectrum of

frequencies. A wide selection of single or multi-channel couplers is available to

provide power and signal processing for the hammer and accelerometers

(KRISTLER, 2011).

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3.4.2 Accelerometer

Figure 3.6: Accelerometer

An accelerometer is a sensing element that measures acceleration; acceleration is the

rate of change of velocity with respect to time. It is a vector that has magnitude and

direction. Accelerometers measure in units of g – a g is the acceleration measurement

of gravity which is equal to 9.81m/s². Accelerometers can measure: vibrations,

shocks, tilt, impacts and motion of an object (KRISTLER, 2011).

A piezoelectric accelerometer consists of the sensor case, the piezoelectric

measuring element and seismic mass. Accelerometers can be based on various

principles, but compression and shear are particularly popular. The quartz element

produces an electric charge that is proportional to the force and hence to the

acceleration. A piezoelectric accelerometer is generally AC-coupled and unsuitable

for measuring static accelerations. The measuring element of this piezoelectric

accelerometer also generates an electric charge that is proportional to the force and

hence to the acceleration.

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