BUILDING SCIENCE 2 (BLD61303) PROJECT 1: LIGHTING AND ACOUSTICS PERFORMANCE EVALUATION AND DESIGN
TUTOR: MR SIVA GROUP MEMBERS: DANIEL ZAIN BIN MAZALAN ESTHER LIM QIU QIU FELICIA TIONG YING MIN SEAN WEE YEN XHIONG TAN CUI ZHI
TABLE OF CONTENTS Introduction…………………………………………………………………………………………………………………………………………1 Aims and Objectives Site Information - Site introduction and site selection reasons - Technical drawings ---------------------------------------------------------------------------------------------------------------------------------PART I: LIGHTING 1.0 Literature Review……………………………………………………………………………………………………………………………4 1.1 Introduction 1.2 Lumen and luminous flux 1.3 Illuminance 1.4 Luminance and brightness 1.5 Lighting in architecture 2.0 Precedent Study…………………………….……………………………………………………………………………………………….5 2.1 Offices of a Finnish Research Unit 3.0 Research Methodology…………………………………………………………………………………………………………………12 3.1 Light Measuring Equipment 3.2 Data Collection Method 4.0 Analysis……………………………………………………………….……………………………………………………………………….14 4.1 Tabulation of data 4.2 Lux Contour diagram for artificial lighting 4.3 Site study 4.3.1 Types of existing artificial lighting 4.3.2 Reflectance values of existing materials 4.4 Lumen method calculations and analysis 5.0 Conclusion…………………………………………………………………………………………………………………………..……….34 6.0 References……………………………………………………………………………………………………………………………………35
Part II: ACOUSTICS 1.0 Literature Review………………………………………………………………………………………………………………….………36 1.1 Introduction 1.2 Sound 1.3 Frequency and wavelength 1.4 Magnitude 1.5 Reverberation time 1.6 Sound absorption and sound absorption coefficient 2.0 Precedent Study…………………………….……………………………………………………………………………………………..37 2.1 Acoustical Quality in Office Workstations, as Assessed by Occupant Surveys 3.0 Research Methodology…………………………………………………………………………………………………………………40 3.1 Acoustic Measuring Equipment 3.2 Data Collection Method 4.0 Analysis…………………………………………………………………………………………………….………………………………….42 4.1 Outdoor noise 4.2 Tabulation of data 4.3 Site study 4.3.1 Absorption coefficient of existing materials 4.4 Calculations 4.4.1 Reverberation Time (RT) 4.4.2 Sound Pressure Level (SPL) 4.4.3 Sound Reduction Index (SRI) 5.0 Conclusion…………………………………………………………………………………………………………………………….……..74 6.0 References…………………………………………………………………………………………………………………………………...77 ---------------------------------------------------------------------------------------------------------------------------------A3 Summaries……………………………………………………………………………………………………………………….……………79
INTRODUCTION The health and safety of users is heavily dependent on lighting in the workplace. A hazard can be more easily avoided if it can be seen quickly and easily - therefore, the types of hazards present will determine the requirements for safe operations. Poor quality of light can affect the health of working people - causing eyestrain, migraines, headaches, and so on. Priorities must be identified, and targets for improvements set by employers, as a variety of human needs must be satisfied by workplace lighting. Lighting also affects many other aspects of a user’s wellbeing: Comfort, social communications, mood, health, safety, and aesthetic judgement. Control of sound within a space or spaces - especially enclosed ones - are what is covered by the element of acoustic design. Eliminating noise and undesired sound is essential to preserve and enhance the desired sound. Prestigious buildings are those in which the acoustics of the building and its spaces will ultimately define the quality of the building itself. Acoustics comprise of both physics and psychology - establishing a satisfactory environment and providing good hearing conditions are among the objectives of noise control. Noise elimination is not to be confused with noise control, as complete quietness is not always necessarily an ideal noise condition. In a team of five, we carried out a lighting and acoustics performance evaluation at Merdekarya. We measured the all functional spaces and divided them into five zones - the stage, seating area, DJ station, bar, and smoking area - shown in the floor and ceiling plans. Lux and sound pressure level meters were employed to determine the lighting and acoustic performance. Measurements of illuminance and sound level were taken during peak hours (9.00pm-11.00pm) and off-peak hours (7.00pm-9.00pm) to address lighting and acoustic related issues. In this report we will critically analyse our findings and present features which affect lighting and acoustic conditions in visual forms - photos, sketches, diagrams, and scale drawings.
Aims and Objectives
To understand lighting and acoustic characteristics and acoustic requirements within a space To determine the characteristics and functions of day-lighting and artificial lighting and sound and acoustics within a space To critically report and analyse a space and suggest solutions to improve the quality of lighting and acoustics within the space
Site Information Merdekarya is a bar and performing arts venue, and functions as an independent bookstore, music store, and live event venue. It is located at Petaling Garden, Section 5, in Petaling Jaya, Selangor, on the first floor of a corner shop lot. We chose Merdekarya as our case study as we felt that it had very significant issues in terms of lighting and acoustics, and as such, had a lot of potential to become a more enjoyable space if these issues were to be discussed and fixed.
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Fig 1.1 - Location plan.
Fig 1.2 & 1.3 - The stage and seating area.
Fig 1.4 & 1.5 - The bar and the smoking lounge area.
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Fig 1.6 - Floor plan with location of all the zones at Merdekarya.
The main spaces at Merdekarya are the stage, the seating area where customers sit and listen to the performers, the DJ station for making announcements, the bar, and the smoking area.
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PART I: LIGHTING 1.0 Literature Review 1.1 Introduction Light is defined as the electromagnetic radiation which is visible to the human eye. Lighting is essential to humans to enable them to visually perceive objects and their environment and without it, we could not exist. At the same time, the intensity of light can directly impact a person’s physiological and psychological well-being, which ultimately affects their ability to perform daily tasks. 1.2 Lumen and Luminous Flux Lumen (lm) is the SI unit of luminous flux, and is equal to the intensity of light emitted per second from a uniform source of one candela, pointing in a specific direction on a solid angle called the steradian. Luminous flux is the total amount of light emitted by a light source and is measured in lumens. 1.3 Illuminance Illuminance is the unit of measurement used to determine the total amount of light falling on a surface. It is measured in Lux (lx), whereby 1 lux is produced by 1 lumen of light shining on an area of one square meter. 1.4 Brightness and Luminance Luminance is a measure of the objective brightness of a light source and indicates the amount of light perceived by an individual in a space after reflection or transmission from a surface; brightness is not a measurable property and is the term used to refer to the subjective perception of an individual to light in a space. Brightness of a space is affected by luminance. 1.5 Lighting in Architecture Lighting can be divided into three main categories: general (or ambient), task, and accent. General lighting provides overall illumination in a space, task lighting is specified for a specific task, such as reading or writing; and accent lighting is used to highlight or accentuate special features in a space, such as decoration and artwork. From an architectural perspective, it is important to integrate and balance both daylight and artificial light in a space. This is important to ensure a quality environment and health of its users.
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2.0 PRECEDENT STUDY 2.1 Offices of a Finnish Research Unit Place: Finland (Helsinki) Building type: Office building
Fig. 2.1.1 - Photos of the office rooms.
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Fig. 2.1.2 - Office plan with the luminaries’ position.
The average installed lighting power density is 13.86 W/m². The ceiling height varies between 2.26 m and 2.94 m. The installation height of the luminaries is 2.26 m and the height of the work plane is 0.72 m. Each office room has daylight availability and are used between 7 am and 5:30 pm, except on weekends.
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Fig. 2.1.3 - Characteristics of luminaries (photometry, geometry, pictures), part one.
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Fig. 2.1.4 - Characteristics of luminaries (photometry, geometry, pictures), part two.
8
Fig. 2.1.5 - Characteristics of luminaries (photometry, geometry, pictures), part three.
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The average illuminances on work planes at full power inside the office rooms:
Table 2.1.1 - Illuminances on work planes in the office rooms.
In the Hall: Eaverage = 293 lx, Uniformity = 0.40 In the kitchen: Eaverage = 177 lx, Uniformity = 0.92 In the toilet room: Eaverage = 337 lx, Uniformity = 0.82 Illuminances on the work planes of the three rooms lowered (use of dimming control) by their occupants Room G436: Eaverage = 545 lx (80%), Uniformity = 0.7 Room G437: Eaverage = 448 lx (73%), Uniformity = 0.57 Room G440: Eaverage = 586 lx (80%), Uniformity = 0.77
Luminances in the fied of vision for the different positions in the office rooms reached 20000 cd/m². The UGR, depending on the positions, varied between 5.7 and 19.2. In the hall, the maximum luminance in the field of vision was 50 000 cd/m². Ratios of the average luminances of work planes, walls, ceilings, and floor to desktop screen luminances are given in the table below:
Table 2.1.2 - Ratio of the average luminances to desktop screen luminances.
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The occupants of the office rooms were interviewed to examine their preferences for the installed lighting system. These occupants were all right-handed people and 56% of them wear glasses. About 75% of the occupant’s work time was spent working on computer screens. The result of the interview is listed below:
19% of the occupants say they suffer from headache at the end of the workday 6% of the occupants are not satisfied with their workspace All appreciate the colour of the artificial light (3000K) 56% of the occupants never change the settings of the lighting control system, whereas 25% of them change it weekly
Room 435 – LON system with dimmer: 25% of the users asked for improvements in lighting for reading-writing tasks No negative opinions about computer work or other tasks Some occupants were not satisfied with the lighting control system
Room 436-437 – MIMO-LON system (presence sensors and daylight): Great comfort for reading-writing tasks No negative opinions about computer work or other tasks 40% of the occupants were not fully satisfied with the lighting control system
Rooms 438-441 – DIGIDIM system (presence sensors): No negative opinion for the reading-writing tasks No negative opinions about computer work or other tasks 14% of the occupants were not fully satisfied with the lighting control system
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3.0 RESEARCH METHODOLOGY 3.1 Light Measuring Equipment (a) Digital Lux Meter:
Fig 3.1.1 - Digital Lux Meter.
Sensor utilises exclusive photo diode and Built-in low battery indicator multicolour correction filters (spectrum meets C.I.E. standards) Sensor COS correction factor meets standards LSI-circuit use provides high reliability and durability Separate light sensor allows user to take LCD display consumes little power measurements at optimum positions Precise and easy readout with wide range Compact, lightweight, easy to operate High-accuracy measuring LCD display can clearly display readouts even with high ambient light (b) Camera: The camera is used to capture the conditions of lighting in the space, as well as the lighting appliances. (c) Measuring Tape: The measuring tape is used to measure the height of positions of the lux meter from standing position (1.5m) and also sitting position (1m). We also used it to measure the 1.5m x 1.5m grid on the floor while recording readings.
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3.2 Data Collection Method The Digital Lux Meter has been used during the collection of data for lighting in Merdekarya. The meter was placed at 1m (sitting level) and 1.5m (standing level) above the ground and took down readings. Every 1.5m apart, at every intersection of the gridline, a reading is taken. The procedure was carried out more than once to ensure the accuracy of our readings. Firstly, we identified the gridlines - 1.5m x 1.5m distance within the site’s floor plan - to record data. We then placed the device at the designated positions - 1m and 1.5m - to obtain the data with the lux meter (in cd/m²). After that, we specified the type of lighting used in that space. The same procedure was repeated for each area, based on the gridlines, at a different time. Lastly, we tabulated and calculated the collected data and referred to MS 1525 to determine the light quality in the space. 1. Identify 1.5m x 1.5m gridline distance 2. Place the device at 1m and 1.5 respectively 3. Specify type of lighting used in the space 4. Repeat same procedure at a different time 5. Tabulate and calculate data
Fig 3.2 - Testing the digital lux meter before taking readings.
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4.0 ANALYSIS 4.1 Tabulation of Data
Fig 4.1.1 - Zones at Merdekarya Artificial lighting (1.0m)
Artificial lighting (1.5m) 1
2
3
4
5
1
2
3
4
5
A
2.0
2.0
4.0
2.0
1.0
A
11.0 9.0
11.0 2.0
1.0
B
1.0
2.0
3.0
1.0
1.0
B
1.0
1.0
2.0
2.0
1.0
C
1.0
1.0
2.0
1.0
1.0
C
1.0
1.0
5.0
2.0
2.0
D
1.0
3.0
3.0
2.0
1.0
D
1.0
4.0
3.0
2.0
1.0
E
2.0
3.0
5.0
4.0
2.0
E
2.0
4.0
4.0
3.0
1.0
F
2.0
3.0
4.0
5.0
3.0
F
2.0
4.0
4.0
3.0
1.0
G
2.0
4.0
2.0
2.0
1.0
G
2.0
10.0 2.0
3.0
2.0
H
3.0
2.0
2.0
2.0
10.0
H
2.0
1.0
1.0
3.0
1.0
I
2.0
5.0
4.0
3.0
2.0
I
3.0
9.0
17.0 6.0
2.0
J
2.0
2.0
3.0
2.0
2.0
J
2.0
2.0
2.0
4.0
2.0
K
1.0
2.0
2.0
3.0
2.0
K
1.0
4.0
3.0
15.0 2.0
L
1.0
2.0
2.0
3.0
2.0
L
2.0
2.0
9.0
3.0
2.0
M
1.0
1.0
4.0
2.0
2.0
M 1.0
1.0
2.0
2.0
2.0
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4.2 Lux Contour Diagram for Artificial Lighting
Fig 4.2.1 Artificial lighting lux contour diagram. Based on the lux diagram, it can be observed that the general lighting of the space is very poor. The quality of light stays the same throughout non-peak and peak hours.
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4.3 Site study 4.3.1 Types of Existing Artificial Lighting (a) Incandescent bulb
Fig 4.3.1 - Incandescent bulb
Fig 4.3.2 - Floor plan with location of ceiling-mounted and wall-mounted incandescent bulbs.
Fig 4.3.3 - Section with location of ceiling-mounted and wall-mounted incandescent bulbs. Product Brand
Lamp Luminous Flux
Rated Colour Temperature
Power
Osram
505 lm
2600 K
240 V
Fig 4.3.4- General specifications of the incandescent bulb used.
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(b) Spotlight
Fig 4.3.5 - Spotlight
Fig 4.3.6 - Floor plan with location of spotlights.
Fig 4.3.7- Section with location of spotlights.
Product Brand
Lamp Luminous Flux
Rated Colour Temperature
Colour Rendering Index
Beam Angle
Power
Phillips
1110 lm
3500 K
100
30°
240 V
Fig 4.3.8- General specifications of the type of spotlight used.
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(c) Fluorescent tube
Fig 4.3.9 - Fluorescent tube
Fig 4.3.10 - Floor plan with location of fluorescent tube.
Fig 4.3.11- Section with location of fluorescent tube.
Product Brand
Lamp Luminous Rated Flux Colour Temperature
Colour Rendering Power Index
Phillips
1350 lm
82
4100 K
Fig 4.3.12- General specifications of the type of fluorescent tube used.
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59 V
4.3.2 Reflectance Values of Existing Materials Zone 1: Stage
1 2 3 4 5 M
L
K
J
I
H
G
F
E
D
C
B
A
Fig 4.3.13- Location of stage.
Component
Materials
Colour
Surface finish
Wall
Wood pallet Curtain Curtain Mineral wool
Brown Black White Black
Glossy Matte Matte Rough
Reflectance value (%) 20 5 80 5
Floor
Carpet
Grey
Rough
0
Ceiling
Acoustical ceiling tiles
Black
Matte
5
Furniture
Wooden table
Brown
Glossy
20
19
Zone 2: Seating Area
1 2 3 4 5 M
L
K
J
I
H
G
F
E
D
C
B
A
Fig 4.3.14- Location of seating area.
Component
Materials
Colour
Surface finish
Wall
Brick wall Orange Brick wall with White plaster
Rough Matte
Reflectance value (%) 15 80
Floor
Stone tiles
Grey
Glossy
10
Ceiling
Acoustical ceiling Black tiles
Matte
5
Furniture
Wooden table Cushion stools Rattan sofa Steel barrel
Glossy Matte Rough Glossy
20 30 20 15
Brown Red Brown Blue
20
Zone 3: DJ Station
1 2 3 4 5 M
L
K
J
I
H
G
F
E
D
C
B
A
Fig 4.3.15- Location of DJ station.
Component
Materials
Colour
Surface finish
Wall
Carpet
Grey
Rough
Reflectance value (%) 0
Floor
Stone
Grey
Glossy
10
Ceiling
Acoustical ceiling tiles
Black
Matte
5
Furniture
Wooden table
Brown
Glossy
20
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Zone 4: Bar
1 2 3 4 5 M
L
K
J
I
H
G
F
E
D
C
B
A
Fig 4.3.16- Location of bar.
Component
Materials
Wall
Brick wall plaster
Floor
Ceramic tiles
Ceiling
Acoustical tiles
Furniture
Wooden table Cushioned stools
with
Colour
Surface finish
White
Matte
Reflectance value (%) 80
Orange
Glossy
30
Matte
5
Glossy Matte
20 30
ceiling Black
Brown Red
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Zone 5: Smoking area
1 2 3 4 5 M
L
K
J
I
H
G
F
E
D
C
B
A
Fig 4.3.17- Location of smoking area.
Component
Materials
Colour
Surface finish
White
Matte
Reflectance value (%) 80
Wall
Brick wall plaster
Floor
Concrete
Grey
Matte
40
Ceiling
Acoustical tiles
ceiling Black
Matte
5
Furniture
Steel barrel Cushioned stools
Glossy Matte
15 30
with
Red Red
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4.4 Lumen Method Calculations and Analysis Zone 1: Stage
1 2 3 4 5 M
L
K
J
I
H
G
F
E
D
C
B
Fig 4.4.1- Location of stage.
Dimension of room (m)
L= 7 W=3.25
Area / A (m2)
22.75
Type of lighting fixture
Wall mounted incandescent
Number of lighting fixtures
5
Luminous flux of lamp / F (lm)
505
Height of luminaire (m) Work level (m) Mounting height (Hm)
3.4 0.9 2.5
Reflectance value
Ceiling: Acoustical tile, black (0.3) Floor: Carpet, grey (0.1) Wall: Curtain, black and white (0.3)
Room index / RI = LxW (L + W)Hm
7 x 3.25 (7 + 3.25)2.5 = 0.89
Utilisation factor
0.26
Standard illuminance level
150 lux
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A
Number of lamps required / N = ExA F x UF x MF
150 x 22.75 505 x 0.26 x 0.8 = 32.5 = 33 lamps According to MS1525, this zone requires 33 lamps to fulfil the standard of 150 lux. 33 lamps - 5 lamps = 28 lamps Therefore, this zone requires an additional 28 lamps in order to fulfil the standard illuminance level.
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Zone 2: Seating Area
1 2 3 4 5 M
L
K
J
I
H
G
F
E
D
C
B
A
Fig 4.4.2- Location of seating area.
Dimension of room (m)
L= 8.1 W=7
Area / A (m2)
56.7
Type of lighting fixture
Spotlight
Wall-mounted incandescent
Ceiling-mounted incandescent
Number of lighting fixtures
3
2
5
Luminous flux of lamp / F (lm)
1110
505
505
Height of luminaire (m) Work level (m) Mounting height (Hm)
3.4 0.9 2.5
Reflectance value
Ceiling: Acoustical tile, black (0.3) Floor: Stone tile, grey (0.1) Wall: Plaster, white (0.5)
Room index / RI = LxW (L + W)Hm
= 8.1 x 7 (8.1 + 7)2.5 =1.44
Utilisation factor
0.37
Standard illuminance level
150 lux
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Number of lamps required / N = ExA F x UF x MF
150 x 56.7 1110 x 0.37 x 0.8 = 25.8 = 26
150 x 56.7 505 x 0.37 x 0.8 = 56.9 = 57
150 x 56.7 505 x 0.37 x 0.8 = 56.9 = 57
According to MS1525, this zone requires 26 lamps to fulfil the standard of 150 lux.
According to MS1525, this zone requires 57 lamps to fulfil the standard of 150 lux.
According to MS1525, this zone requires 57 lamps to fulfil the standard of 150 lux.
26 lamps - 3 lamps = 23 lamps 57 lamps - 2 lamps = 55 lamps Therefore, this zone requires an Therefore, this additional 23 lamps zone requires an in order to fulfil the additional 55 standard lamps in order to illuminance level. fulfil the standard illuminance level.
57 lamps - 5 lamps = 52 lamps
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Therefore, this zone requires an additional 52 lamps in order to fulfil the standard illuminance level.
Zone 3: DJ Station
1 2 3 4 5 M
L
K
J
I
H
G
F
E
D
C
Fig 4.4.3- Location of DJ station.
Dimension of room (m)
L= 2.5 W=1
Area / A (m2)
2.5
Type of lighting fixture
Fluorescent tube
Number of lighting fixtures
1
Luminous flux of lamp / F (lm)
1350
Height of luminaire (m) Work level (m) Mounting height (Hm)
1.2 0.9 0.3
Reflectance value
Ceiling: Acoustical tile, black (0.3) Floor: Stone tile, grey (0.1) Wall: Carpet, grey (0.1)
Room index / RI = LxW (L + W)Hm
2.5 x 1 (2.5 + 1)0.3 = 2.38
Utilisation factor
0.4
Standard illuminance level
150 lux
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B
A
Number of lamps required / N = ExA F x UF x MF
150 x 2.5 1350 x 0.4 x 0.8 = 0.9 = 1 lamp According to MS1525, this zone requires 1 lamp to fulfil the standard of 150 lux. 1 lamp – 1 lamp = 0 lamps Therefore, this zone has met and fulfiled the standard illuminance level.
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Zone 4: Bar
1 2 3 4 5 M
L
K
J
I
H
G
F
E
D
C
Fig 4.4.4- Location of bar.
Dimension of room (m)
L= 6.8 W=3.4
Area / A (m2)
23.12
Type of lighting fixture
Ceiling-mounted incandescent
Number of lighting fixtures
2
Luminous flux of lamp / F (lm)
505
Height of luminaire (m) Work level (m) Mounting height (Hm)
2.5 1.0 1.5
Reflectance value
Ceiling: Acoustical tile, black (0.3) Floor: Tile, orange (0.3) Wall: Plaster, white (0.5)
Room index / RI = LxW (L + W)Hm
6.8 x 3.4 (6.8 + 3.4)1.5 = 1.5
Utilisation factor
0.42
Standard illuminance level
150 lux
30
B
A
Number of lamps required / N = ExA F x UF x MF
150 x 23.12 505 x 0.42 x 0.8 = 20.4 = 21 lamps According to MS1525, this zone requires 21 lamps to fulfil the standard of 150 lux. 21 lamps - 2 lamps = 19 lamps Therefore, this zone requires an additional 19 lamps in order to fulfil the standard illuminance level.
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Zone 5: Smoking area
1 2 3 4 5 M
L
K
J
I
H
G
F
E
D
C
Fig 4.4.5- Location of smoking area.
Dimension of room (m)
L= 6.7 W=3.4
Area / A (m2)
22.78
Type of lighting fixture
Ceiling-mounted incandescent
Number of lighting fixtures
2
Luminous flux of lamp / F (lm)
505
Height of luminaire (m) Work level (m) Mounting height (Hm)
2.5 0.9 1.6
Reflectance value
Ceiling: Acoustical tile, black (0.3) Floor: Concrete, grey (0.3) Wall: Plaster, white (0.5)
Room index / RI = LxW (L + W)Hm
6.7 x 3.4 (6.7 + 3.4)1.6 = 1.4
Utilisation factor
0.42
Standard illuminance level
150 lux
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B
A
Number of lamps required / N = ExA F x UF x MF
150 x 22.78 505 x 0.39 x 0.8 = 21.7 = 22 lamps According to MS1525, this zone requires 22 lamps to fulfil the standard of 150 lux. 22 lamps - 2 lamps = 20 lamps Therefore, this zone requires an additional 20 lamps in order to fulfil the standard illuminance level.
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5.0 Conclusion Since Merdekarya only opens at night (starting 7 p.m.), there is no source of natural lighting. Moreover, the lounge is totally closed off and all the windows have been covered or sealed. Apart from the lounge not having any natural light, the choice of ambient lighting used is very poor as well. The general artificial lighting used in Merdekarya are incandescent lamps. Because of this, it was very hard for us to read and record data on site. Based on the digital lux meter readings and lux contour diagram, it is very evident that Merdekarya is very poorly lit. According to the calculations, all the zones except the DJ station do not meet the MS1525 standard required illuminance of 150 lux for the space of a lounge. This is due to the poor choice of artificial lighting used, as well as the lack of the number of lamps installed.
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6.0 REFERENCES
1. Chapter 10: Case studies. (2016). 1st ed. [ebook] pp.250-259. Available at: http://www.lightinglab.fi/IEAAnnex45/guidebook/10_case%20studies.pdf [Accessed 31 May 2016]. 2. Higo, J. (2016). Measure Foot Lamberts. [online] Illumicaregroup.com. Available at: http://www.illumicaregroup.com/2012/11/03/foot-lamberts-explained/ [Accessed 31 May 2016]. 3. Schiler, M. (1992). Simplified design of building lighting. New York: Wiley. 4. Stein, B., Reynolds, J. and McGuinness, W. (1992). Mechanical and electrical equipment for buildings. New York: J. Wiley & Sons. 5. Winchip, S. (2008). Fundamentals of lighting. New York: Fairchild Publications.
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PART II: ACOUSTICS
1.0 LITERATURE REVIEW 1.1 Introduction From an architectural perspective, the acoustical environment in and around buildings is influenced by various interrelated factors, from building development to selection of site, and even the arrangement of spaces within a building. It is important to understand the basic properties of sound and how it functions through different building spaces and materials in order to effectively control the acoustical environment of a building. 1.2 Sound A sound wave is the pattern of disturbance caused by the movement of energy travelling through a medium (solid, liquid, or air) as it moves away from the source of sound. The vibration disturbs the particle in the surrounding medium, the particles disturb those next to them, and so on. 1.3 Frequency and Wavelength The frequency of a sound wave is the number of complete vibrations and is referred to as pitch. This basic rate of repetition of the vibrations defines its character. The unit of measure is the hertz (Hz). Wavelength, also related to frequency, is the distance within which the complete cycle of disturbance occurs. The velocity of sound is equal to the frequency times the wavelength. 1.4 Magnitude The magnitude, or intensity, of sound is defined as the acoustical energy contained in a sound wave. It is proportional to the amplitude of the disturbance of pressure. Because of the wide range of frequencies, as well as the way the human ear responds to sound, a measurement unit called the decibel (dB) has been adopted for sound level measurements. 1.5 Reverberation Time Reverberation can be described as the persistence of sound an individual hears in a room which is continuously reflected by the room’s boundaries, then gradually decays as it is absorbed by the surfaces of objects in the room. Hence, reverberation time is the amount of time, in seconds, it takes for a sound to decay after the source of sound stops. 1.6 Sound Absorption and Sound Absorption Coefficient Sound absorption is the reduction in the sound energy after striking a surface through the change of sound energy into another form of energy, usually heat. In relation to this, sound absorption coefficient is the ability of a particular material to absorb sound.
36
2.0 PRECEDENT STUDY 2.1 Acoustical Quality in Office Workstations, as Assessed by Occupant Surveys Abstract The case study is an analysis on acoustic satisfaction in office environments in buildings surveyed by the Center for the Built Environment (CBE). A total of 23,450 respondents from 142 buildings were included in the analysis. Acoustic satisfaction in the CBE survey is a function of satisfaction with both noise, and speech privacy. Based on the survey, people are significantly more dissatisfied with speech privacy than noise level, and occupants in private offices are significantly more satisfied with the acoustics than occupants in cubicles. Also, occupants in open office environments are significantly more satisfied with noise level and speech privacy than occupants working in cubicles. Over 50% of cubicle occupants think acoustics interfere with their ability to get their job done.
Research Methods The obtained data is divided into subjective and objective variables. A subjective variable could be an occupant’s satisfaction with the noise level or satisfaction with the sound privacy level where the occupants vote on a 7-point satisfaction scale ranging from -3 to 3. Objective variables are demographic or other background data, such as gender and office type. Physical factors relevant to the acoustic analysis such as phones ringing, people talking, noise from HVAC systems etc., are also found in the branching drill-down questions that follow dissatisfied votes.
Results The following results are based on data from a total of 23,540 respondents from the CBE database.
Figure 2.1.1 - Average scores for the nine core categories and two acoustic satisfaction questions in the Occupant Indoor Environmental Quality (IEQ) survey. The acoustic category score is calculated as an average of the satisfaction scores of two acoustic questions: satisfaction with the noise level and satisfaction with speech privacy. The low level of satisfaction with speech privacy reduces the average acoustic category score. If the data are divided by office type, the difference between the two acoustic satisfaction questions become clearer. 37
Figure 2.1.2 - Average acoustic satisfaction score according to office type. From the figure above, the difference between private offices and cubicles in average satisfaction is clearly seen. The figure also shows the big difference in satisfaction between the two acoustic questions. People tend to be more dissatisfied with speech privacy than noise level. In cubicles with partitions, both categories are negative with an average score for satisfaction with speech privacy of -1.57 and -1.61, respectively. In contrast, people working in open office environments seem to be more satisfied with both noise and speech privacy. The office occupants were asked if the acoustic quality in their workspace enhanced or interfered with their ability to get their job done. The figure below shows this distribution for each office type.
Figure 2.1.3- Percentage of occupants who indicate that acoustic quality enhances, interferes, or has a neutral effect on their ability to get their job done. Over 50% of occupants in cubicles and approximately 30% of occupants in private and shared offices think that poor acoustics interfere with their daily work. However, as many as 50% of the occupants in private and shared offices stated that their acoustical environment enhances their ability to get their job done. It is likely that such positive ratings reflect the respondents’ awareness of the alternatives to their private office acoustics (cubicle and open-office acoustics). Occupants in partitionless open offices think that acoustics interfere less with their work than do occupants in cubicles.
38
When survey respondents express dissatisfaction with acoustics, they are asked further questions to allow the identification of specific causes for dissatisfaction. The table below lists the percentages of occupants dissatisfied with a certain problem, in descending order of prevalence, divided by office types.
Table 2.1.1 - Percentage of occupants dissatisfied with the acoustics. The table shows that dissatisfaction priorities are almost the same in all office types, and that people are mostly dissatisfied with hearing other people talking on telephones, people overhearing private conversations, and the sound of people talking in surrounding offices.
Conclusion and Implications Office workers are significantly more dissatisfied with the lack of speech privacy than with the level of noise. Occupants in open office environments are more satisfied with noise and speech privacy than occupants in cubicles.
39
3.0 RESEARCH METHODOLOGY 3.1 Acoustic Measuring Equipment (a) Sound Level Meter
Fig 3.1.1 - Sound Level Meter.
Main functions are designed to meet IEC 61672 Class 2 standards
Manual data-logger is available (setting sampling time to 0 seconds), set different positions and numbers when executing A&C weighting networks comply with standards Innovative and easy to operate - computer not needed to set up extra software, just plug in SD card to download all measured values to Excel directly 0.5� standard microphone head SD card capacity: 1 - 16 GB Time weighting (fast and slow) dynamic LCD with green backlight for easy reading characteristic modes Build External calibration VR Can be set to power off automatically or manually Auto- and manual-range selection Hold data, record maximum and minimum readings Available for external calibration adjustments Microcomputer circuit for high accuracy Condenser microphone for high accuracy and Powered by 6 UM3/AA (1.5V) or DC 9V adapter long-term stability Memory function to store the maximum and R232/USB PC computer interface minimum value Hold and peak hold functions Heavy duty and compact housing case Real-time SD memory card data-logger, built-in clock and calendar, real-time data recorder, sampling time (set from 1 - 3,600 seconds) (b) Camera: The camera is used to capture the acoustic equipment utilised within the space.
40
(c) Measuring Tape: The measuring tape is used to measure 1.5m x 1.5m grid on the floor while recording readings.
3.2 Data Collection Method The Sound Level Meter has been used during the collection of data for acoustics in Merdekarya. The meter was placed every 1.5m apart, at every intersection of the gridline, and the reading is taken. The procedure was carried out more than once to ensure the accuracy of our readings. Firstly, we identified the gridlines - 1.5m x 1.5m distance within the site’s floor plan - to record data. After that, we specified the source of sound within that space. The same procedure was repeated for each area, based on the gridlines, at a different time. Lastly, we tabulated and calculated the collected data and referred to MS 1525 to determine the light quality in the space.
1. Identify 1.5m x 1.5m gridline distance 2. Place the device at 1.5m and 1m 3. Specify acoustic devices used in the space 4. Repeat same procedure at a different time 5. Tabulate and calculate data
Fig 3.2.1 - Taking readings with the sound level meter.
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4.0 ANALYSIS 4.1 Outdoor Noise Merdekarya is located in a residential area and is within close proximity to a bus stop located at the intersection of Jalan 5/53 and Jalan 5/46. Most of the outdoor noise originates from activity from nearby shops as well as vehicular activities that occur along the main road which directly faces Merdekarya. At night, activities such as dancing and exercising can also be heard from the nearby park.
Fig 4.1.1- Location plan of Merdekarya and sources of outdoor noise.
Fig 4.1.2 - The row of shophouses and park which surrounds Merdekarya.
42
4.2 Tabulation of data OFF-PEAK (7 p.m.) 1
2
3
4
5
A
81.5
73.0
71.2
65.6
75.4
B
84.0
78.0
75.9
74.2
76.4
C
95.2
83.0
78.0
80.5
92.2
D
90.5
76.1
79.6
85.2
84.1
E
79.4
80.2
83.4
85.8
80.4
F
70.3
72.8
78.9
79.3
79.7
G
75.2
78.4
76.8
81.8
83.0
H
83.4
80.4
70.0
65.9
63.4
I
82.4
81.0
78.1
72.5
74.3
J
83.0
83.2
64.1
73.2
74.4
K
81.2
80.1
70.1
68.4
67.7
L
80.7
80.3
76.9
67.8
74.2
M
80.7
75.9
70.9
70.0
82.2
PEAK (9.30 p.m.) 1
2
3
4
5
A
86.0
78.0
76.9
70.2
80.4
B
89.5
83.0
80.2
79.6
81.4
C
97.5
88.1
83.6
85.2
97.1
D
95.2
81.0
84.0
90.5
89.2
E
84.3
85.8
88.9
90.3
85.7
F
75.4
77.2
83.4
84.8
84.4
G
80.4
83.4
81.0
86.9
88.4
H
88.2
85.4
75.8
70.8
68.0
I
87.0
86.2
83.1
75.2
76.4
J
88.4
88.0
69.1
75.5
76.3
K
86.7
85.3
75.9
70.8
70.2
L
85.2
85.1
81.1
70.4
76.7
M
85.3
80.1
75.1
72.5
84.3
43
Fig 4.2.1 and 4.2.2 - Representations of sound intensity during off-peak and peak hours, respectively. During performances, the volume is increased, but the smoking area remains almost unaffected.
61-65 dB 66-70 dB 71-75 dB 76-80 dB 81-85 dB 86-90 dB 91-95 dB
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4.3 Site Study 4.3.1 Absorption Coefficients of Existing Materials Components
Image
Absorption Coefficient 500 Hz
Plaster Wall
0.01
Location
2000 Hz
0.02
Performance Stage, Listening Area, MC Station, Counter/ Bar Area, Smoking Area
Performance Stage, Listening Area, MC Station Acoustic Wall Carpet
0.15
0.75
Listening Area, Counter/ Bar Area Bare Brick Wall
0.03
0.04
Performance Stage, Listening Area Sound Absorption Drapery
0.40
45
0.50
Wooden Table
0.22
Metal Stool
0.15
0.38
0.18
Performance Stage, Listening Area, MC Station, Counter/ Bar Area
Performance Stage, Listening Area, MC Station, Counter/ Bar Area, Smoking Area
Listening Area Rattan Sofa
0.77
0.82
Listening Area, Smoking Area
Steel Barrel
0.44
Dropped Ceiling
0.66
46
0.54
0.88
Performance Stage, Listening Area, MC Station, Counter/ Bar Area, Smoking Area
Performance Stage, Carpet
0.40
0.50
Listening Area, MC Station
Stone Flooring
0.02
0.05
Counter/ Bar Area, Smoking Area Ceramic Tile Floor
0.03
0.05
Counter/ Bar Area
Wood Door
0.06
47
0.10
4.4 Calculations 4.4.1 Reverberation Time Material absorption coefficient during non- peak hours:
Type
Walls
Curtains
Furniture
Ceiling
Floor
Door
Material
Surface Area (m2)
Function
Absorption Coefficient
Sound Absorption
500 Hz
2000 Hz
500 Hz
2000 Hz
125.84 251.68
Plaster
Wall + Wall Finishing
125.83
0.01
0.02
Acoustic Wall Carpet
Wall + Wall Finishing
60.32
0.15
0.75
9.05
45.24
Brick
Wall
16.88
0.03
0.04
0.51
0.68
Sound Absorption Drapery
Sound Proofing/Partition/ Divider
47.72
0.40
0.50
19.09
23.86
Wooden Table
Table
2.16
0.22
0.38
0.48
0.82
Metal Stool
Chair
4.03
0.15
0.18
0.60
0.73
Rattan Sofa
Sofa
1.15
0.77
0.82
0.89
0.94
Steel Barrel
Table
1.42
0.44
0.54
0.62
0.77
Dropped Ceiling
Ceiling
128.11
0.66
0.88
84.55
112.74
Carpet
Floor
22.75
0.40
0.50
9.10
11.38
Stone Flooring
Floor
59.15
0.02
0.05
1.18
2.96
Ceramic Tiles
Floor
43.26
0.03
0.05
1.30
2.16
Wood
Door
5.76
0.06
0.10
0.35
0.58
5
0.42
0.5
2.1
2.5
People (Non-Peak) Total
255.66 457.04
48
Volume of spaces: Performance Stage:
22.75 m2 x 3.2 m = 72.8 m3
Listening Area:
[(47.5m x 7 m) x 3.2 m] + [(3.7 m x 7 m) x 3.2 m] = 106.4 m3 + 82.88 m3 = 189.28 m3
MC Station:
2.5 m2 x 3.2 m = 8 m3
Counter/Bar Area:
23.42 m2 x 3.2 m = 74.98 m3
Smoking Area:
22.78 m2 x 3.2 m = 72.90 m3
Total Volume of Space: 72.8 m3 + 189.28 m3 + 8 m3 + 74.98 m3 + 72.90 m3 = 417.96 m3
Reverberation Time (500Hz) = (0.16 x V)/A = (0.16 x 417.96 m3)/255.66 = 0.26 s
Reverberation Time (2000Hz) = (0.16 x V)/A = (0.16 x 417.96 m3)/457.04 = 0.15 s
49
Material absorption coefficients during peak hours:
Type
Material
Curtains
Function
Wall + Finishing
Wall
Acoustic Wall Wall + Carpet Finishing
Wall
Plaster Walls
Absorption Surface Area Coefficient (m2) 500 2000
Sound Absorption 500 Hz
2000 Hz
Hz
Hz
125.83
0.01
0.02
125.84 251.68
60.32
0.15
0.75
9.05
45.24
Brick
Wall
16.88
0.03
0.04
0.51
0.68
Sound Absorption Drapery
Sound Proofing/Partition/ 47.72 Divider
0.40
0.50
19.09
23.86
Wooden Table Table
2.16
0.22
0.38
0.48
0.82
Metal Stool
Chair
4.03
0.15
0.18
0.60
0.73
Rattan Sofa
Sofa
1.15
0.77
0.82
0.89
0.94
Steel Barrel
Table
1.42
0.44
0.54
0.62
0.77
Dropped Ceiling
Ceiling
128.11
0.66
0.88
84.55
112.74
Carpet
Floor
22.75
0.40
0.50
9.10
11.38
Stone Flooring Floor
59.15
0.02
0.05
1.18
2.96
Ceramic Tiles
Floor
43.26
0.03
0.05
1.30
2.16
Wood
Door
5.76
0.06
0.10
0.35
0.58
24
0.42
0.5
10.08
12.00
Furniture
Ceiling
Floor
Door People (Non-Peak) Total
263.64 466.54
50
Volume of spaces: Performance Stage: 22.75 m2 x 3.2 m = 72.8 m3 Listening Area:
[(47.5m x 7 m) x 3.2 m] + [(3.7 m x 7 m) x 3.2 m] = 106.4 m3 + 82.88 m3 = 189.28 m3
MC Station:
2.5 m2 x 3.2 m = 8 m3
Counter/Bar Area:
23.42 m2 x 3.2 m = 74.98 m3
Smoking Area:
22.78 m2 x 3.2 m = 72.90 m3
Total Volume of Space: 72.8 m3 + 189.28 m3 + 8 m3 + 74.98 m3 + 72.90 m3 = 417.96 m3
Reverberation Time (500Hz) = (0.16 x V)/A = (0.16 x 417.96)/263.64 = 0.25 s Reverberation Time (2000Hz) = (0.16 x V)/A = (0.16 x 417.96)/466.54 = 0.14 s
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Analysis:
Merderkarya (Total)
Merderkarya (Peak)
Merderkarya (Non-Peak)
2000 Hz 500 Hz
Average Recording Studio
Average Bar/Resturant 0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
Reverberation Time (Seconds)
The reverberation time during non-peak hour ranges from 0.15 – 0.26 seconds and the reverberation time during Peak hours ranges from 0.14 – 0.25 seconds. In short, the total reverberation time ranges from 0.14 – 0.26 seconds. The average reverberation time for a bar/restaurant ranges from 0.7 – 0.8 seconds. However, the bar itself has integrated a number of sound proofing elements similar to that of a recording studio (which ranges from 0.3 – 0.4 seconds) to allow bands and singers to be as loud as they please while dissipating sound to prevent echoes. In comparison to a bar’s average reverberation time, the bar exceeds the requirements (0.14 – 0.26 seconds to 0.7 – 0.8 seconds). However, in comparison to a recording studio, the bar succeeded the requirements (0.14 – 0.26 seconds to 0.3 – 0.4 seconds).
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4.4.2 Sound Pressure Level (SPL) Zone 1: Stage
1 2 3 4 5 M
L
K
J
I
H
G
F
E
D
C
B
A
Acoustic (dB)
1
2
3
4
5
A
81.5
73
71.2
65.6
75.4
B
84
78
75.9
74.2
76.4
C
95.2
83
78
80.5
92.2
i) Non-Peak Hours Highest Reading: 95.2 d Using the Formula; L = 10 log10 ( l / 1 x 10-12) 95.2 = 10 log10 ( l / 1 x 10-12) l
= ( 109.52) (1 x 10-12)
l
= 3.31 x 10-3
Lowest Reading: 71.2 dB Using the Formula; L = 10 log10 ( l / 1 x 10-12) 71.2 = 10 log10 ( l / 1 x 10-12) l
= ( 107.12) (1 x 10-12)
l
= 1.32 x 10-5
53
Total Intensities = (3.31 x 10-3) + (1.32 x 10-5) = 3.32 x 10-3 Combined SPL = 10 log10 ( p2/ po2 ), Where po = 1 x 10-12 Combined SPL = 10 log10 [(3.32 x 10-3) / (1 x 10-12)] = 10 x 9.52 = 95.2 dB
Acoustic (dB)
1
2
3
4
5
A
86.0
78.0
76.9
70.2
80.4
B
89.5
83.0
80.2
79.6
81.4
C
98.6
88.1
83.6
85.2
97.1
ii) Peak Hours Highest Reading: 98.6 dB Using the Formula; L = 10 log10 ( l / 1 x 10-12) 98.6 = 10 log10 ( l / 1 x 10-12) l
= ( 109.86) (1 x 10-12)
l
= 7.24 x 10-3
Lowest Reading: 70.2 dB Using the Formula; L = 10 log10 ( l / 1 x 10-12) 70.2 = 10 log10 ( l / 1 x 10-12) l
= ( 107.02) (1 x 10-12)
l
= 1.05 x 10-5
Total Intensities = (7.24 x 10-3) + (1.05 x 10-5) = 7.25 x 10-3
54
Combined SPL = 10 log10 ( p2/ po2 ), Where po = 1 x 10-12 Combined SPL = 10 log10 [(7.25 x 10-3) / (1 x 10-12)] = 10 x 9.86 = 98.6 dB
55
Zone 2: Seating Area
1 2 3 4 5 M
L
K
J
I
H
G
F
E
D
C
B
A
Acoustic (dB)
1
2
3
4
5
D
90.5
76.1
79.6
85.2
84.1
E
79.4
80.2
83.4
85.8
80.4
F
70.3
72.8
78.9
79.3
79.7
G
75.2
78.4
76.8
81.2
83
H
83.4
80.4
70
i) Non-Peak Hours Highest Reading: 90.5 dB Using the Formula; L = 10 log10 ( l / 1 x 10-12) 90.5 = 10 log10 ( l / 1 x 10-12) l
= ( 109.05) (1 x 10-12)
l
= 1.12 x 10-3
Lowest Reading: 70.0 dB Using the Formula; L = 10 log10 ( l / 1 x 10-12) 70.0 = 10 log10 ( l / 1 x 10-12) l
= ( 107.00) (1 x 10-12)
l
= 1.00 x 10-5
56
Total Intensities = (1.12 x 10-3) + (1.00 x 10-5) = 1.13 x 10-3
Combined SPL = 10 log10 ( p2/ po2 ), Where po = 1 x 10-12 Combined SPL = 10 log10 [(1.13 x 10-3) / (1 x 10-12)] = 10 x 9.05 = 90.5 dB
Acoustic (dB)
1
2
3
4
5
D
95.2
81.0
84.0
90.5
89.2
E
84.3
85.8
88.9
90.3
85.7
F
75.4
77.2
83.4
84.8
84.4
G
80.4
83.4
81.0
86.9
88.4
H
88.2
85.4
75.8
ii) Peak Hours Highest Reading: 95.2 dB Using the Formula; L = 10 log10 ( l / 1 x 10-12) 95.2 = 10 log10 ( l / 1 x 10-12) l
= ( 109.52) (1 x 10-12)
l
= 3.31 x 10-3
Using the Formula; L = 10 log10 ( l / 1 x 10-12) 75.4 = 10 log10 ( l / 1 x 10-12) l
= ( 107.54) (1 x 10-12)
l
= 3.47 x 10-5
Total Intensities = (3.31 x 10-3) + (3.47 x 10-5) = 3.34 x 10-3
57
Combined SPL = 10 log10 ( p2/ po2 ), Where po = 1 x 10-12 Combined SPL = 10 log10 [(3.34 x 10-3) / (1 x 10-12)] = 10 x 9.52 = 95.2 dB
58
Zone 3: DJ Station
1 2 3 4 5 M
Acoustic (dB)
L
K
1
J
I
H
G
2
3
H
i) Non-Peak Hours Highest Reading: 65.9 dB Using the Formula; L = 10 log10 ( l / 1 x 10-12) 65.9 = 10 log10 ( l / 1 x 10-12) l
= ( 106.59) (1 x 10-12)
l
= 3.89 x 10-6
Lowest Reading: 63.4 dB Using the Formula; L = 10 log10 ( l / 1 x 10-12) 63.4 = 10 log10 ( l / 1 x 10-12) l
= ( 106.34) (1 x 10-12)
l
= 2.19 x 10-6
F
Total Intensities = (3.89 x 10-6) + (2.19 x 10-6) = 6.08 x 10-6
59
E
D
C
B
A
4
5
65.9
63.4
Combined SPL = 10 log10 ( p2/ po2 ), Where po = 1 x 10-12 Combined SPL = 10 log10 [(6.08 x 10-6) /(1 x 10-12)] = 10 x 6.78 = 67.8 dB
Acoustic (dB)
1
2
3
H
ii) Peak Hours Highest Reading: 70.8 dB Using the Formula; L = 10 log10 ( l / 1 x 10-12) 70.8 = 10 log10 ( l / 1 x 10-12) l
= ( 107.80) (1 x 10-12)
l
= 6.31 x 10-5
Lowest Reading: 68.0 dB Using the Formula; L = 10 log10 ( l / 1 x 10-12) 68.0 = 10 log10 ( l / 1 x 10-12) l
= ( 106.80) (1 x 10-12)
l
= 6.31 x 10-6
Total Intensities = (6.31 x 10-5) + (6.31 x 10-6) = 6.94 x 10-5
Combined SPL = 10 log10 ( p2/ po2 ), Where po = 1 x 10-12 Combined SPL = 10 log10 [(6.94 x 10-5) / (1 x 10-12)] = 10 x 7.84 = 78.4 dB
60
4
5
70.8
68.0
Zone 4: Bar
1 2 3 4 5 M
L
K
J
I
H
G
F
Acoustic (dB)
1
2
3
I
82.4
81
78.1
J
83
83.2
64.1
K
81.2
80.1
70.1
L
80.7
80.3
76.9
M
80.7
75.9
70.9
i) Non-Peak Hours Highest Reading: 83.2 dB Using the Formula; L = 10 log10 ( l / 1 x 10-12) 83.2 = 10 log10 ( l / 1 x 10-12) l
= ( 108.32) (1 x 10-12)
l
= 2.09 x 10-4
Lowest Reading: 64.1 dB Using the Formula; L = 10 log10 ( l / 1 x 10-12) 64.1 = 10 log10 ( l / 1 x 10-12) l
= ( 106.41) (1 x 10-12)
l
= 2.57 x 10-6
61
E
D
C
B
A
Total Intensities = (2.09 x 10-4) + (2.57 x 10-6) = 2.16 x 10-4
Combined SPL = 10 log10 ( p2/ po2 ), Where po = 1 x 10-12 Combined SPL = 10 log10 [(2.16 x 10-4) / (1 x 10-12)] = 10 x 8.33 = 83.3 dB
Acoustic (dB)
1
2
3
I
87.0
86.2
83.1
J
88.4
88.0
69.1
K
86.7
85.3
75.9
L
85.2
85.1
81,1
M
85.3
80.1
75.1
ii) Peak Hours Highest Reading: 88.4 dB Using the Formula; L = 10 log10 ( l / 1 x 10-12) 88.4 = 10 log10 ( l / 1 x 10-12) l
= ( 108.84) (1 x 10-12)
l
= 6.92 x 10-4
Lowest Reading: 69.1 dB Using the Formula; L = 10 log10 ( l / 1 x 10-12) 69.1 = 10 log10 ( l / 1 x 10-12) l
= ( 106.91) (1 x 10-12)
l
= 8.13 x 10-6
Total Intensities = (6.92 x 10-4) + (8.13 x 10-6) = 7.00 x 10-4
62
Combined SPL = 10 log10 ( p2/ po2 ), Where po = 1 x 10-12 Combined SPL = 10 log10 [(7.00 x 10-4) / (1 x 10-12)] = 10 x 8.85 = 88.5 dB
63
Zone 5: Smoking Area
1 2 3 4 5 M
L
K
J
I
Acoustic (dB)
4
5
I
72.5
74.3
J
73.2
74.4
K
68.4
67.7
L
67.8
74.2
M
70
82.2
H
G
i) Non-Peak Hours Highest Reading: 82.2 dB Using the Formula; L = 10 log10 ( l / 1 x 10-12) 82.2 = 10 log10 ( l / 1 x 10-12) l
= ( 108.22) (1 x 10-12)
l
= 1.66 x 10-4
Lowest Reading: 67.7 dB Using the Formula; L = 10 log10 ( l / 1 x 10-12) 67.7 = 10 log10 ( l / 1 x 10-12) l
= ( 106.77) (1 x 10-12)
l
= 5.89 x 10-6
64
F
E
D
C
B
A
Total Intensities = (1.66 x 10-4) + (5.89 x 10-6) = 1.72 x 10-4
Combined SPL = 10 log10 ( p2/ po2 ), Where po = 1 x 10-12 Combined SPL = 10 log10 [(1.72 x 10-4) / (1 x 10-12)] = 10 x 8.24 = 82.4 dB
Acoustic (dB)
4
5
I
75.2
76.4
J
75.5
76.3
K
70.8
70.2
L
70.4
76.7
M
72.5
84.3
ii) Peak Hours Highest Reading: 84.3 dB Using the Formula; L = 10 log10 ( l / 1 x 10-12) 84.3 = 10 log10 ( l / 1 x 10-12) l
= ( 108.43) (1 x 10-12)
l
= 2.69 x 10-4
Lowest Reading: 70.2 dB Using the Formula; L = 10 log10 ( l / 1 x 10-12) 70.2 = 10 log10 ( l / 1 x 10-12) l
= ( 107.02) (1 x 10-12)
l
= 1.05 x 10-5
Total Intensities = (2.69 x 10-4) + (1.05 x 10-5) = 2.80 x 10-4
65
Combined SPL = 10 log10 ( p2/ po2 ), Where po = 1 x 10-12 Combined SPL = 10 log10 [(2.80 x 10-4) / (1 x 10-12)] = 10 x 8.45 = 84.5 dB
66
4.4.3 Sound Reduction Index (SRI) Zone 1: Stage
1 2 3 4 5 M
L
K
J
I
H
Building Elements
Materials
Walls
Concrete w/ 49 plaster finish
G
F
E
D
C
B
Sound Reduction Transmission Index (SRI) Coefficient (T) 1.26 x 10-5
Using the formula: 10 log10 1/T Concrete w/ plaster finish Walls: 49 = log10 1 / T = 1 / (104.9) = 1.26 x 10-5
Toverall = 44.64 x (1.26 x 10-5) 44.64 = 1.26 x 10-5
Overall SRI = 10 log10 1 / T = 10 log10 (1/ 1.26 x 10-5) = 44 dB
67
A
Area (S/m2)
44.64
Zone 2: Seating Area
1 2 3 4 5 M
L
K
J
I
H
G
F
E
D
C
B
Sound Reduction Transmission Index (SRI) Coefficient (T)
A
Building Elements
Materials
Walls
Concrete w/ 49 plaster finish
1.26 x 10-5
27.27
Walls
Brick
3.98 x 10-5
11.84
44
Using the formula: 10 log10 1/T Concrete w/ plaster finish Walls: 49 = log10 1 / T = 1 / (104.9) = 1.26 x 10-5
Brick Walls: 44 = log10 1 / T = 1 / (104.4) = 3.98 x 10-5
68
Area (S/m2)
Toverall = [27.27 x (1.26 x 10-5)] + [11.84 x (3.98 x 10-5)] 27.27 + 11.84 = (3.436 x 10-4) + (4.712 x 10-4) 39.11 = 2.08 x 10-5
Overall SRI = 10 log10 1 / T = 10 log10 (1/ 2.08 x 10-5) = 10 log10 (4.808 x 104) = 46.8 dB
69
Zone 3: DJ Station
1 2 3 4 5 M
L
J
K
I
H
G
F
Building Elements
Materials
Walls
Concrete w/ 49 plaster finish
E
Sound Reduction Index (SRI)
Using the formula: 10 log10 1/T Concrete w/ plaster finish Walls: 49 = log10 1 / T = 1 / (104.9) = 1.26 x 10-5
Toverall = 7.84 x (1.26 x 10-5) 7.84 = 1.26 x 10-5
Overall SRI = 10 log10 1 / T = 10 log10 (1/ 1.26 x 10-5) = 49 dB
70
D
C
B
A
Transmission Coefficient (T)
Area (S/m2)
1.26 x 10-5
7.84
Zone 4: Bar
1 2 3 4 5 M
L
K
J
I
H
G
F
E
D
C
B
Sound Reduction Transmission Index (SRI) Coefficient (T)
A
Building Elements
Materials
Walls
Concrete w/ 49 plaster finish
1.26 x 10-5
19.68
Walls
Brick
44
3.98 x 10-5
5.04
Doors
Timber
22
6.31 x 10-3
3.78
Using the formula: 10 log10 1/T Concrete w/ plaster finish Walls: 49 = log10 1 / T = 1 / (104.9) = 1.26 x 10-5
Brick Walls: 44 = log10 1 / T = 1 / (104.4) = 3.98 x 10-5
71
Area (S/m2)
Timber Doors: 22 = log10 1 / T = 1 / (102.2) = 6.31 x 10-3 Toverall = [19.68 x (1.26 x 10-5)] + [5.04 x (3.98 x 10-5)] + [3.78 x (6.31 x 10-3)] 19.68 + 5.04 + 3.78 = (2.48 x 10-4) + (1.76 x 10-4) + (2.385 x 10-2) 28.50 = 8.52 x 10-4
Overall SRI = 10 log10 1 / T = 10 log10 (1/ 8.52 x 10-4) = 10 log10 (1.174 x 103) = 30.7 dB
72
Zone 5: Smoking area
1 2 3 4 5 M
L
K
J
I
H
Building Elements
Materials
Walls
Concrete w/ 49 plaster finish
G
F
E
D
C
B
Sound Reduction Transmission Index (SRI) Coefficient (T) 1.26 x 10-5
Using the formula: 10 log10 1/T Concrete w/ plaster finish Walls: 49 = log10 1 / T = 1 / (104.9) = 1.26 x 10-5
Toverall = 34.24 x (1.26 x 10-5) 34.24 = 1.26 x 10-5
Overall SRI = 10 log10 1 / T = 10 log10 (1/ 1.26 x 10-5) = 49 dB
73
A
Area (S/m2)
34.24
5.0 CONCLUSION
Fig 4.1 - The various zones and materiality. As seen from Fig 4.1 above, the space above shows the 2 types of wall and locations of various doors. This space is unique in that it does not have any windows, it is a custom space designed and created similar to a performing arts auditorium. The area mainly consists of plastered walls which 74
provide a decent amount of sound reduction, and brick walls were exposed for aesthetics rather than practicality. The doors are made of timber as most standard doors are today.
Sound Reduction Index Performance Area
Listening Area
DJ Station
Sound Reduction Index
Bar/Counter Area
Smoking Area 0
10
20
30
40
50
60
Fig 4.2 - The various SRI values.
Performance Area: 49 dB Listening Area: 46.8 dB DJ Station: 49 dB Bar/Counter Area: 30.7 dB Smoking Area: 49 Db
According to Fig 4.2 above, the Bar/Counter Area stood out the most where it is the lowest among the rest. This is due to the fact that there are doors located at the bottom corner of the space. The doors allows sound to travel through the doors more easily since they are not as thick and dense as concrete walls. Sound energy can also escape easier when the doors open, which is what the owner anticipated, so in response, all the doors are located towards the back half of the space. All the spaces have similar SRI mainly due to having the same materials surrounding the space. The space’s reverberation time is significantly short also due it being an enclosed space without too many openings. Although the sound produced inside the space ranges from 83.8 – 89.0 dB (average) in comparison to the (average) SRI of 44.9 dB, the main contributors of sound absorption are the sound proof curtains and wall carpet panels. This reduces the sound transfer to the outer space which results in minimal noise leakage to the outside. However, according to The Planning Guidelines For Environmental Noise Limits and Control (Department of Environment Ministry of Natural Resources and Environment Malaysia), Annex A, a suburban residential of medium density should not 75
exceed the sound levels of 55 dB at night. Merderkarya reaches sounds of up to 98 dB which conclusively exceeds the allowed decibels for a suburban area. The space itself have not succeed the requirement for a bar/restaurant, however, as a recording studio (which was the bar’s secondary alternative), it met the required standards. Merderkarya uses various ways to prevent noise to leak through to the surrounding neighbourhood, which include: Sound-proofing carpet wall panels and sound proof curtains. However, Merderkarya exceeds the allowed decibels for a building in suburban area of medium density. In conclusion, although exceeding the sound limit for building, it was able to contain and nullify it within the area and minimising noise leakage.
76
6.0 REFERENCES
1. Cavanaugh, W. and Wilkes, J. (1999). Architectural acoustics. New York: Wiley. 2. D. (n.d.). Acoustic Properties of Curtain Wall [Abstract]. Retrieved May 25, 2016, from http://www.service.hkpc.org/hkiemat/previous/2008/mastec03_notes/CFNG.PDF 3. D. (n.d.). Building acoustics 2.4.4. Retrieved http://www.kayelaby.npl.co.uk/general_physics/2_4/2_4_4.html
May
24,
2016,
from
4. IBARAHIM, D. R. (n.d.). Environmental Noise Limits and Control. Retrieved May 26, 2016, from http://www.gunungganang.com.my/pdf/Malaysian-Policies-StandardsGuidelines/Guidelines/Planning Guidelines for Environmental Noise Limits and Contro.pdf 5. McMullan, R. (1998). Environmental science in building. Basingstoke, England: Macmillan. 6. Milne, G., Banfield, K., & Reardon, C. (2013). Noise control. Retrieved May 25, 2016, from http://www.yourhome.gov.au/housing/noise-control 7. Noise Protection Curtains. (n.d.). Retrieved May http://www.mbakustik.de/produkt/schallschutzvorhaenge/?lang=en
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from