Building Science 2 [ARC 3413]
Project 1 Lighting & Acoustic Performance Evaluation and Design
Group Members
Tutor
:
:
Cynthia Lee Siaw Wun
0306112
Deidre Zhang Shu-Wei
0304619
Gan Sue Jing
0307957
Lee Jia Xin
0308389
Wong Yoke Lin
0308254
Mr. Rizal
Table of Content 1.0
Abstract
2.0
Introduction 2.1 Site 2.1.1 Reason of Selection 2.1.2 Site Issues 2.2 Light 2.2.1 Importance of Lighting in Architecture 2.2.2 Lighting Design within a Cafe 2.2.3 Precedent Study 2.2.4 Methodology of Light Analysis
3.0
2.3
Lighting Equipment Specification
2.4
Lighting Data Tabulation
Light Data Analysis 3.1 Surrounding Light Factor 3.2 Natural Daylighting 3.3 Existing Light Specification 3.4 Material Analysis and Lumen Method Calculation 3.5 Daylight Factor Calculation 3.6 Building Material Specification 3.7 Furniture Material Specification
4.0
Acoustic 4.1 Importance of Acoustic in Architecture 4.1.1 Architectural acoustics 4.1.2 Sound pressure level (SPL) 4.1.3 Reverberation Time
4.1.4 Sound reduction index (SRI) 4.2
Precedent Study
4.3
Methodology of Acoustic Analysis
4.4
Acoustic Equipment Specification
4.5
Acoustic Data Tabulation
5.0 Acoustic Data Analysis 5.1 Source of Noise 5.1.1 Outdoor noise 5.1.2 Indoor noise 5.1.3 Reverberation Time, RT 5.1.4 Sound Pressure Level, (SPL)
6.0 Conclusion
7.0 References
1.0 Abstract In architecture, lighting and acoustic design play significant roles in creating the most optimum environment for its users. The qualities of a space can only truly be appreciated when it is imaginatively lit. The successful unification of the lighting of buildings and the lighting of its activities is what unifies the building and makes it interpretable to its users to its best capabilities. In acoustics, desired sounds are enhanced and undesired sounds are eliminated to create comfortable and conducive environments in relation to its functionality. As both lighting and acoustics play such dire roles in the making of the atmosphere of a space, it is crucial to take into account the many considerations required. Thus, thorough studies based on standards and requirements for lighting and acoustics should be included in the design process. Another site analysis is also carried out to study and understand the day lighting & lighting and acoustic characteristics & acoustic requirement in a suggested space. This assignment is intended to be completed in a group of 5 students to evaluate the environment of choosing in terms of lighting and acoustics performance. A case study is to be selected and measured drawings are to be produced, along with an appraisal of daylighting, artificial lighting, noise and sound conditions of the selected case study. Site conditions such as weather, building orientation, site surroundings and times of day have to be taken into consideration.
2.0 Introduction 2.1 Site
Case Study
:
Greyskymorning
Type of space
:
CafĂŠ
Total floor area
:
210.28 m2
Address
:
EX8, No. 3 Jalan SS13/4, Subang Jaya
Located in the industrial areas of SS13, Greyskymorning café is a gem tucked away in the midst of factories and office blocks. It is an urban infill, wedged between City Harvest Church and an eatery called Food Industrie. Through a conversational interview with the owner, it was informed that the play of natural lighting was of much importance to the design of the space as much of it could be utilised. The materials were left bare, so as to retain the raw aesthetic of the space. Operating hours of the café is from 11AM to 9PM, but crowds are drawn in primarily in the afternoon, specifically on Sundays, when church services end. In terms of lighting, different types of light fixtures located at different parts of the café accommodate the different hours of the day where necessary. 2.1.1 Reason of Selection The case study was selected first and foremost because of its play of natural and artificial lighting, as well as its acoustics. In terms of lighting, Greyskymorning thoroughly exploits the availability of natural light penetrating into their building by having transparent facades, as well as an opaque roof material. The cafe also has an interesting variety of light fixtures to create the desired ambiance within the cafe. The lighting of some parts of the cafe may not be suitable or viable, and several amendments can be considered to improve the quality of lighting in the space. In terms of acoustics, it was discovered that a church was located beside the cafe. Therefore the reason of selection was to study how the activities of the church would affect the acoustics of the cafe, on top of the existing sound conditions in the cafe. 2.1.2 Site Issues As the building facades are transparent, ample penetration of natural lighting occurs. However, at certain times of the day, more specifically during the daytime, it is found that this condition is not very suitable for the users as the intensity of glare is very high and causes slight visual discomfort. During night time, it is found that the artificial lighting within the building is insufficient at certain areas, which also causes visual discomfort to its users.
In terms of acoustics, external factors such as church band practice, activities from neighboring buildings, as well as the noise from the air-conditioning compressors affect the overall acoustical quality of the café. Within the cafe, the reflectance of sound is high as the surfaces in the cafe are mostly smooth and hard surfaces. There are little to no soft surfaces or acoustical considerations taken to absorb the extra noise of music, human activities as well as sounds of the coffee machines.
2.2 Light 2.2.1 Importance of Lighting in Architecture Lights create a feeling of emotions. It is able to control people’s behavior and emotions. Light is the soul of architecture design, it not only enhance visual to allow us to see and feel, light also makes it possible for us to express and show to the mind’s eye thing that eludes the physical ones. The present or absent of light can dramatically transform the atmosphere of a space depending on its brightness, lighting colour and positioning. However, if a space is not being illuminated properly, the user will not be able to experience the designed space at its fullest. The process in choosing the right lighting is delicate as it can ruin the experience of users in the designed space if not being designed properly. It requires special guidelines for creating quality, illuminated environments. The lighting function is a physiological problem that must be addressed practically rather than emotionally or intellectually. It includes:
Identifying the use of building or space Size Standard of visual comfort Times of day the space is in use Required illumination levels Distribution of light for adequate performance Choice of illuminant Amount of permissible/desirable distraction Contrast of lighting equipment and its background
2.2.2 Lighting Design within a Cafe Cafe is a gathering spot in a building space. Architects and designer has to take consideration when designing the space in the café as it will give an impact to the people’s daily life as well as the frequent customers of the cafes. Restaurant owners will realize the importance of lighting design and how it will impact their customers by creating a specific ambience for their customers. The perception of space is directly connected to the way light integrates with it. What we see will affect the way we experience. Light constitutes an element of fundamental relevance for the design spaces, good lighting clarifies and stimulates positivity. Overall lighting color can impact a guest’s comfort level from the beginning of the meal to its completion. Proper lighting plays a key role in creating that right ambience for customers to enjoy dining in. Another crucial factor that affects lighting design is the materials and finishes used in the café. Individual sources of light can be reflected depending on the materials used for finishes, which will create the intensity without a need for additional light sources. Lighting fixtures can also be used to separate spaces without the use of partitions. Studies shows that lighting is the key in creating the ambience within a space in which affects perceptions on the responsiveness and reliability of the customer, the rate and amount of their consumption, the amount of time that is spent in the restaurant. It goes to show that creating the right kind of ambience increases the customers’ satisfaction towards the café, hence securing high level demand and marketing achievement.
2.2.3 Precedent Study 2.2.3.1 Introduction
Figure 2.2.3.1a: Overview of Kemuri Shanghai Restaurant.
Project
:
Kemuri Shanghai Restaurant
Architect
:
Prism Design
Location
:
Shanghai, China
Design Team
:
Tomohiro Katsuki, Masanori Kobayashi, Reiji Kobayashi
Project Year
:
2012
Construction Cp.
:
Shanghai Zhao Bo Zhuang Huang Engineerings & Construction Ltd
Lighting
:
Nvc Lighting Technology Corporation
The owner’s design requirements had two special themes: 1. taking inspiration from the movie “Kill Bill”, and the occidental angle to show the Asian culture; 2. Kemuri, which means
smoke in Japanese, to be represented along the design. Prism Design aimed to produce a mysterious atmosphere, reflecting both themes to produce a unique and experiential dining environment.
2.2.3.2 Design Strategies Minimalist lighting is used to create a relaxed atmosphere. The chosen fixtures, both task lighting and ambient lighting have colour temperatures of about 2700K, ideal for relaxed dining and to convey the design concept of the restaurant. Fluorescent, incandescent, spot light and down lights are identified.
Figure 2.2.3.2a:
Lighting is used to highlight the textures of the materials used as well as provide ambient dining space for its patrons.
Figure 2.2.3.2b:
Figure shows the several types of light fixtures used: spotlights, uplights, down lights as well as concealed fluorescent lights.
Figure 2.2.3.2c: LED up-lights are used along the edges of the walls to aid in atmospheric quality as well as pave the spaces of the restaurant.
Figure 2.2.3.2d:
The ambience created by the play of lighting positioning and intensities throughout the space.
Incandescent light fixtures have low colour temperature and high CRI which cast warm light that provides a comfortable dining environment as well as good colour renders within the space. However, incandescent lightings are inefficient as they give off heat. This is because light is produced by heating the tungsten until it glows, therefore the energy consumed by this action is given off as heat. In countering this issue, materials such as rice papers, rattan strips are used to diffuse lighting as well as heat barriers which enhance the dining experience without the bother of the heat source.
Figure 2.2.3.2e: Bar area.
A higher luminous intensity is required at the bar to perform tasks, hence the ceiling is lowered to create a focused area of light intensity.
Figure 2.2.3.2f: Reflective materials on walls.
The architect also took advantage of material use to reflect light into the space. Materials such as smooth, finished concrete has high reflectivity, which was utilised by the architect to manipulate the light fixtures creatively. This way, the space is brightened with just enough amounts of lighting.
Figure 2.2.3.2g:
Section showing heights of light fixtures.
Figure 2.2.3.2h:
Section showing lighting height and material use at bar area.
2.2.3 Methodology of Light Analysis Timeline of Lighting Tabulation DATE
SITE VISIT
4 Apr 15
RECORDING INFORMATION
5 Apr 15 10 Apr 15
TABULATING DATA
DISCUSSING & ANALYSING
13 Apr 15 15 Apr 15
19 Apr 15
21 Apr 15
DIAGRAMMING & WRITING THE REPORT
Site Visit: -
The initial approach of visual observations and recordings data, measured drawing, documenting through photos and interviews session with the person in charge.
Recording Information: -
The lighting data is recorded using a lux meter equipment according to grid positions on the floor plan.
Tabulating Data: -
The process of tabulating light data into proper formats, according to grid lines on the floor plan is for easier reference.
Discussing & Analyzing:
-
In this stage, lighting data is analyzed along with research evidence.
Diagramming & Writing the Report: -
Lighting data and analytical research are categorized and organized into the report.
2.3 Lighting Equipment Specification Lighting data is collected according to the gridlines position on the floor plan of Grey Sky Morning Café, using the lux meter provided by Taylor’s University. It is collected accurately by holding the lux meter perpendicular to our eye level [1.5m] and waist level [1m] with the light sensor probe facing upwards. Each data is recorded accordingly to the gridline on the floor plan of Grey Sky Morning Café during the day and night. Lux Meter – Model LX-101
Features:
Built-in low battery indicator. Has high accuracy in measuring. Precise and easy readout, wide range. Sensor COS correction factor meet standard. LCD display provides low power consumption. Compact, lightweight and excellent operation. LSI-circuit use provides high reliable and durability. LCD display can clearly read out even high ambient light. Separate light sensor allows user take measurement of an optimum position. Sensor used the exclusive photo diode & multi-colour correction filters, spectrum meet C.1.E standard.
Lighting Data Tabulation We have a few observation and discussions based on the lighting data tabulation below.
2.4 Lighting Data Tabulation Morning
Afternoon
Night
Observation A: Light data tabulations above show that the readings in the afternoon are higher compare to morning and night time. Discussion A:
During the afternoon, the glare of the sunlight is stronger compare to morning and night time. There are more people in the café. Hence, it created shadows that diffuse the lights.
Observation B: The readings of the light data taken 1.5m above the ground are higher than the readings at 1m above the ground.
Discussion B:
It is nearer to the artificial light source when the lux meter is placed at 1.5m above the ground, hence it received more amount of light. Every point of the grid has different readings between 1m and 1.5m above the ground. The readings will be higher when the lux meter is placed towards both ends of the café.
2.5 Light Contour Diagram
Ground Floor Plan
First Floor Plan
3.0 Light Data Analysis 3.1 Surrounding Light Factor
Ground Floor Plan
First Floor Plan
3.2 Natural Daylighting
3.3 Existing Light Specification Lightbulb 1 Brand
Philips Duramax Clear Long Life Candelabra Bulb
Cap/Fitting
B 10.5
Light Effect
Warm White
Wattage
60W
Voltage
120V
Light Output
550 lumen
Colour Temperature
-
First Floor Plan
Lightbulb 2 Brand
Home Lighting Squirrel Cage Carbon Filament Bulb
Cap/Fitting
E 27
Light Effect
-
Wattage
60W
Voltage
240V
Light Output
240 lumen
Colour Temperature
2700K
Ground Floor Plan
Lightbulb 3 Brand
Philips EcoVantage Vanity Halogen Light Bulb
Cap/Fitting
G 25
Light Effect
Warm White
Wattage
40W
Voltage
120V
Light Output
550 lumen
Colour Temperature
2800K
Ground Floor Plan
Lightbulb 4 Brand
Philips Halogen Spot Light
Cap/Fitting
GU 5.3
Light Effect
Warm White
Wattage
35W
Voltage
12V
Light Output
520 lumen
Colour Temperature
3200K
Ground Floor Plan
First Floor Plan
3.4 Material Analysis and Lumen Method Calculation Required Illuminance for Non-Residential Building (MS1525) Task and examples of application
Illuminance (Lux)
Lighting to infrequently used areas Minimum service illuminance
20
Interior walkway and car-park
50
Hotel bedroom
100
Lift interior
100
Corridor, passageways, stairs
100
Escalator, travellator
150
Entrance and exit
100
Staff changing room, cloak room, lavatories, stores
100
Entrance hall, lobbies, waiting room
100
Inquiry desk
300
Gate house
200
Lighting for working interiors Infrequent reading and writing General offices, shops and stories, reading and writing Drawing office
200
300-400
Restroom
300-400
Restaurant, cafeteria
150
Kitchen
200
Lounge
150-300
Bathroom
150
Toilet
150
Bedroom
100
Classroom, library
100
Shop, supermarket, department store
300-500
Museum and gallery
200-750
Localized lighting for exacting task
300
Proof reading Exacting drawing
500
Detailed and precise work
1000 2000
3.5 Daylight Factor Calculation Daylight factors are used in architecture in order to assess the internal natural lighting levels as perceived on the working plane or surface in question, in order to determine if they will be sufficient for the occupants of the space to carry out their normal duties. It is the ratio of internal light level to external light level. zone Very bright
DF (%) >8
Distribution Very large with thermal and glare issue. Bright 3-5 Good Average 1-3 Fair Dark 0-1 poor Source: Daylight factors and distribution (Department of standards Malaysia, 2007) Ground Floor Zone 1: Bar
time 10am 12pm 8pm
weather Clear sky Clear sky Dark
Luminance at 1m 110-438 107-1033 38-229
average 223.00 580.22 124.78
Time and sky condition 12pm
Luminance at 1.5m 101-347 330-1359 41-272
average 212.44 672.56 119.22
Data collected (lux) outdoor 32000
indoor (580.22 + 672.56) / 2 = 626.39
DF = (Ei / Eo) x 100% = (626.39 / 32000) x 100% = 1.96%
Based on the calculation of daylight factor, Zone 1 has a relatively low DF. It is shown that it has a DF of only 1.96%, and falls under the category average. It does not fulfil the minimal standard daylight factor requirement of MS1525 for outdoor dining area of 2%. The daylight was not enough to light up the space.
Zone 2: Outdoor Dining Area
time 10am 12pm 8pm
weather Clear sky Clear sky Dark
Luminance at 1m 112-1292 991-1533 9-63
average 607.80 1352.00 35.50
Time and sky condition 12pm
Luminance at 1.5m 103-1334 281-1404 9-72
average 669.83 962.33 39.00
Data collected (lux) outdoor 32000
indoor 1157.17
DF = (Ei / Eo) x 100% = (1157.17 / 32000) x 100% = 3.61%
Based on the calculation of daylight factor, Zone 2 has a good DF. It is shown that it has a DF of 3.61%, and falls under the category bright. It exceeded the minimal standard daylight factor requirement of MS1525 for bar area of 2%. The daylight was satisfying in brightening that area.
Zone 3: Indoor dining area
time 10am 12pm 8pm
weather Clear sky Clear sky Dark
Luminance at 1m 51-349 69-1120 1-332
average 160.16 473.68 74.63
Time and sky condition 12pm
Luminance at 1.5m 33-265 71-1072 2-343
average 137.21 414.32 82.84
Data collected (lux) outdoor 32000
indoor (473.68 + 414.32)/2 = 444.00
DF = (Ei / Eo) x 100% = (444.00 / 32000) x 100% = 1.39%
Based on the calculation of daylight factor, Zone 3 has a relatively low DF. It is shown that it has a DF of only 1.39%, and falls under the category average. It does not fulfil the minimal standard daylight factor requirement of MS1525 for dining area of 2%. The daylight was not enough to light up the space.
First floor Zone 4: Outdoor dining area
time 10am 12pm 8pm
weather Clear sky Clear sky Dark
Luminance at 1m 838-1981 540-1611 0-14
average 1409.5 1075.5 7
Time and sky condition 12pm
Luminance at 1.5m 1098-1886 278-1509 0-25
average 1492 893.5 12.5
Data collected (lux) outdoor 32000
indoor (1075.5+893.5) / 2 = 984.5
DF = (Ei / Eo) x 100% = (984.5 / 32000) x 100% = 3.08%
Based on the calculation of daylight factor, Zone 1 has a relatively good DF. It is shown that it has a DF of 3.08%, and falls under the good category. It does fulfill the minimal standard daylight factor requirement of MS1525 for outdoor dining area of 2%. The daylight was enough to light up the space.
Zone 5: Indoor Dining Area
time 10am 12pm 8pm
weather Clear sky Clear sky Dark
Luminance at 1m 553-1931 339-1887 0-181
average 1077.05 1028.89 24.00
Time and sky condition 12pm
Luminance at 1.5m 604-1904 278-1999 0-297
average 1435.28 1287.28 35.33
Data collected (lux) outdoor 32000
indoor (1028.89+ 1287.28) / 2 = 1158.09
DF = (Ei / Eo) x 100% = (1158.09/ 32000) x 100% = 3.62%
Based on the calculation of daylight factor, Zone 5 has a relatively high DF. It is shown that it has a DF of only 3.62%, and falls under the category bright. It does fulfil the maximal standard daylight factor requirement of MS1525 for first floor dining area of 2%. The daylight was enough to light up the space.
Zone 6: Balcony
time 10am 12pm 8pm
weather Clear sky Clear sky Dark
Luminance at 1m 225-1931 657-1441 0-1
average 1078 1049 0.5
Time and sky condition 12pm
Luminance at 1.5m 395-1904 793-1505 0-2
average 1149.5 1149 1
Data collected (lux) outdoor 32000
indoor (1049+1149) / 2 = 1099
DF = (Ei / Eo) x 100% = (1099 / 32000) x 100% = 3.43%
Based on the calculation of daylight factor, Zone 1 has a relatively good DF. It is shown that it has a DF of only 3.43%, and falls under the category average. It does not fulfil the minimal standard daylight factor requirement of MS1525 for bar area of 2%. The daylight was not enough to light up the space.
Zone 7: AC area time weather 10am Clear sky 12pm Clear sky 8pm Dark
Luminance at 1m 225-211 657-625 1-0
average 218.00 641.00 0.50
Time and sky condition 12pm
Luminance at 1.5m 395-387 1067-673 1-0
average 391.00 870.00 0.50
Data collected (lux) outdoor 32000
indoor 755.50
DF = (Ei / Eo) x 100% = (755.50 / 32000) x 100% = 2.36%
Based on the calculation of daylight factor, Zone 2 has a relatively fair DF. It is shown that it has a DF of 2.36%, and falls under the category average. It exceeded the minimal standard daylight factor requirement of MS1525 for bar area of 2%. The daylight was satisfying in brightening that area. Zone Bar Outdoor dining area (GF) Indoor dining area (GF) Outdoor dining area (FF) Indoor dining area (FF) Balcony AC area
Daylighting Factor (%) 1.96 3.61 1.09 3.08 3.62 3.43 2.36
Conclusion dark bright dark bright bright bright average
3.6 Building Material Specification Zone
Bar area
Dining area (groun d floor)
Picture
Area
Material
Colour
Texture
Reflectance Value (%)
Wall
Bricks
Old english red
Rough
20
Floor
Polished Concrete
Grey
Glossy
15
Ceiling
Concrete
Gray
Rough, matte
20
Wall
Glass
Transparent
Glossy
6
Floor
Polished Concrete
Grey
Glossy
15
Dining area (first floor)
Columns
Painted Steel
Black
Glossy
18
Ceiling
Painted Steel
Black
Glossy
18
Under the stairs
Polycarbon ate
Semitransparent
Glossy
10
Wall
Bricks
Old english red
Rough
20
Staircase
Painted Steel
Black
Glossy
18
Floor
Painted Steel Plate
Black
Glossy
18
Wall
Glass
Transparent
Glossy
6
Wall
Concrete
Grey
Rough, Matte
25
Window
Glass
Tinted
Glossy
6
Ceiling
Polycarbon ate
Transparent
Glossy
10
Fencing
Painted Steel
Black
Glossy
18
Wall
Glass
Transparent
Glossy
6
Balcon y (grid A3-5)
Balcon y (Grid J3-5)
Partial of wall
Corrugated steel plate
Grey
Glossy
15
Fencing
Painted Steel
Black
Glossy
18
Floor
Painted Steel plate
Black
Glossy
18
Fencing
Painted Steel
Black
Glossy
18
Floor
Painted Steel
Black
Glossy
18
Wall
Corrugated Steel Plate
Grey
Glossy
15
3.7 Furniture Material Specification Area
Type
Image
Texture
Surface type
Colour
Counter Counter
Smooth Polished wood
Dark brown
Dining area (Groun d floor)
Table
Smooth
Light brown
Chair
Smooth Wood coated with shellac
brown
Bench
Smooth Wood coated with shellac
Dark brown
Table
Smooth Wood coated with shellac
Dark brown
Chair
Smooth Wood coated with shellac
Dark brown
Sofa
Smooth Glossy PU leather
Black
Dining area (first floor)
Reflectanc e value(%)
Balcony
Table
Rough
Wooden pallets
Brown
Bench
Rough
Solid tree trunks
Light brown
Chair
Smooth Wood coated with shellac
Brown
Table
Smooth Metal
Black
4.0 Acoustic 4.1 Importance of Acoustic in Architecture 4.1.1 Architectural acoustics Sound is the sensation stimulated in the organs of hearing by mechanical radiant energy transmitted as longitudinal pressure waves through the air or other medium. It is also reinterpreted by the brain as such waves being received. Acoustics is the branch of physics that deals with the production, control, transmission reception and effects of sounds. It is implied in many aspects of our society such as: music, communication speeches, psychoacoustics, bio-acoustics, electroacoustic, and architectural acoustics. What is architectural acoustics? Architectural acoustics may be defined as the total effect of sound produced in an enclosed space. It is the scientific study of sound, especially of its generation, transmission and reception. Architectural acoustics plays a critical role in controlling sound in spaces. It preserves and enhances desired sound in specific spaces, for example, enhancing the speech quality in a lecture hall. Controlling architectural acoustics also help in reduction or elimination of sound that interfere with activities. Exterior noise to interior of the building could be reduced with the help of building acoustics design, creating a more pleasant environment for specific users and activities, maintaining the space functionality of building spaces.
4.1.2 Sound pressure level (SPL) Sound pressure level (SPL) is the average force of sound on a surface area perpendicular to the direction of the sound. Acoustic system design could be achieved with the study of sound pressure level in a space. Sound pressure is usually measured with microphones. SPL is a logarithmic measure of the effective sound pressure of a sound relative to a reference value. It is expressed in decibels related to the lowest human hearable sound. Sound pressure level formula: SPL= Where, log is the common logarithm; P is the sound pressure; Po is the standart reference pressure of 20 microPascals.
4.1.3 Reverberation Time Reverberation is the continuing presence of sound after the source of the sound has been stopped caused by rapid multiple reflections between the surfaces of the room. Reverberations are heard as an extension to the original sound. When reflection of sound is made and absorbed by surfaces, a reverb is made. Reverberation time is considered in architectural acoustic design as it is critical to achieve optimum performance. Reverberation time formula:
Where, T is the reverberation time in seconds V is the room volume in m3 A is the absorption coefficient
Reverberation time is affected by the area of space and the amount of reflective or absorptive surfaces within a space. As the number of reflective surfaces increase, the number of sound reflection increases, increasing the reverberation time within a space. In contrast, as the number of absorptive surface increase, it will absorb the sound, stopping it from reflecting back to the spaces. Thus, in comparison to smaller spaces, larger spaces have longer reverberation times; therefore larger spaces require more absorptive surface to achieve the same reverberation time as a smaller space.
4.1.4 Sound reduction index (SRI) Sound reduction index (SRI) measures the level of sound insulation provided by certain structure or material. In architectural acoustic design, SRI is important in the aspect of decreasing the sound escaped from loud to quiet space. Sound reduction index formula: SRI=
Where, SRI is sound reduction index in dB; Wi is sound power incident on one side of a sound barrier (W); Wt is sound power transmitted into the air on the side of the partition (W)
4.2 Precedent Study 4.2.1 Introduction
Figure 4.2.1a: Overview of The Cave Restaurant.
Project
:
The Cave Restaurant Sydney “Sushi Train Maroubra”
Architect
:
Koichi Takada Architects
Location
:
Maroubra, Sydney, Australia
Project Team :
Koichi Takada, Robert Chen
Project Year
:
2009
Construction
:
Bonar Interiors
Client
:
Mr. Yoshiki Matsuoka
“We aim to change the way we eat and chat in restaurants.” - Koichi Takada Architects
The Cave Restaurant is more than just a product of unique interior decorating and planning. It has stamped itself as a “place” of familiar identity, offering an escape into “nature” from the urban surroundings. With this project, Koichi Takada Architects aimed to create a space which acoustic qualities contribute to the comfort and enjoyment of the dining experience.
4.2.2 Design Strategy 4.2.2.1 Plywood in Acoustics and Sound Insulation
Figure 4.2.2.1a:
View of curved timber profiles joined from the walls to ceiling.
As mentioned, the curved timber profiles are but just for decoration purposes. Experimentation with noise levels in relation to the comfort of dining was carried out to mimic the ambience of a cave-like environment. The timber profiles function to generate a sound studio atmosphere, and to convert the reflection of sounds within the restaurant such as diners’ conversations into pleasant “noise”. This in turn offers a more intimate experience acoustically on top of being a visually interesting and complex surrounding.
The series of acoustic curvatures were tested and developed with computer modelling to achieve optimum acoustical quality within the restaurant. Each “timber grain� profile was translated and cut from computer-generated 3D data, using Computer Numerical Control (CNC) technology, which is a router that produces consistent and high-quality work, crucial for this project.
Figure 4.2.2.1b: 1.2x2.4m acoustic timber set out.
Figure 4.2.2.1c:
Model showing the shape of the ceiling curvatures.
Figure 4.2.2.1d: 1.2x2.4m acoustic timber profiles.
The curved acoustic timber profiles are made from plywood, which has good acoustic properties as it is an excellent reflector of sound. Plywood is used in theatres and auditoriums because of its low-frequency reverberation control. The fact that plywood is porous is also an aiding factor in acoustic insulation and reduces the energy of the sound waves.
Figure 4.2.2.1e: Slotting of timber profiles.
Figure 4.2.2.1f: Projection, absorption and reflection of sound.
Figure 4.2.2.1g:
Diffusion of sound.
In addition, the spaces between slots also increase the amount of sound absorption, breaking up the energy of the sound wave. Together with the unevenly shaped surface of the ceiling which transmits the sound within the space dynamically and prevents sound concentration due to diffusion and reflection of sound, echoes are significantly reduced.
4.2.2.2 Furniture
Figure 4.2.2.2a:
Wood furniture is used in the restaurant.
The use of timber is also applied in the furniture and floorboards throughout the restaurant due to its high value of absorption coefficient, to absorb excess noise in the space caused by human activities as well as kitchen activities. This can also be seen in Figure 4.2.2.1a above.
4.3 Methodology of Acoustic Analysis Timeline of Acoustic Tabulation DATE
SITE VISIT
4 Apr 15
RECORDING INFORMATION
5 Apr 15
TABULATING DATA
DISCUSSING & ANALYSING
10 Apr 15
12 Apr 15
13 Apr 15 19 Apr 15
21 Apr 15
DIAGRAMMING & WRITING THE REPORT
Site Visit: -
The initial approach of visual observations and recordings data, measured drawing, documenting through photos and interviews session with the person in charge.
Recording Information: -
The acoustic data is recorded using decibel meter equipment according to grid positions on the floor plan.
Tabulating Data: -
The process of tabulating acoustic data into proper formats, according to grid lines on the floor plan is for easier reference.
Discussing & Analyzing: -
In this stage, acoustic data is analyzed along with research evidence.
Diagramming & Writing the Report: -
Acoustic data and analytical research are categorized and organized into the report.
4.4 Acoustic Equipment Specification Acoustic data is collected according to the gridlines position on the floor plan of Grey Sky Morning Café, using the sound level meter provided by Taylor’s University. It is recorded accurately by holding the sound level meter at the waist level [1m] with the sound sensor probe facing upwards. Digital Sound Level Meter
Features:
30-130 dB measurement range. 31.5-8000 Hz frequency. Resolution 0.1 dB. A&C frequency weighting. Fast & slow time weighting. Peak Hold. Data Hold Record (max, min). Alkaline/Heavy Duty DC 1.5V battery (UM3, AA) x 6 pcs.
4.5 Acoustic Data Tabulation We have a few observation and discussions based on the acoustic data tabulation below. Morning
Afternoon
Night
Observation A: The acoustic data collected shows that the readings are significantly higher during the morning and afternoon. The highest reading is at 81, while the readings are lower during the night time. Discussion A: There’s a church event every Sunday beside the café. Thus the readings will be higher during the afternoon, as the café is mostly occupied of people after their church. The sound levels are relatively same, but it is louder at first floor due to the reflection of sound on the raw materials such as glass and steel.
5.0 Acoustic Data Analysis 5.1 Source of Noise 5.1.1 Outdoor noise
5.1.2 Indoor noise
Ground Floor Plan
First Floor Plan
Speaker positions in GreySkyMorning CafĂŠ
5.1.3 Reverberation Time, RT Ground floor Zone 1: Bar
Volume, V= 20.04X3.6= 72.144M2 Material absorption coefficient in 125Hz at peak hour: Building Element
Material
Absorption Coefficient, a (125Hz)
Area, S (m2)
Sxa
Floor
Polished concrete
0.1
20.04
2.004
Wall
Old English red bricks
0.03
3.03
0.09
Wall
Glass
0.18
18.92
3.4
Ceiling
Concrete
0.1
20.04
2.004
Door
Glass
0.3
3.46
1.04
Furniture
Polished wood
0.02
0.14
0.0028
0.21 per person
0
0
Total Absorption, A
8.54
Human
RT= (0.16 x V) / A = (0.16 x 72.14)/8.54 = 1.35s
Material absorption coefficient in 500Hz at peak hour: Building Element
Material
Absorption Coefficient, a (500Hz)
Area, S/m2
Sxa
Floor
Polished concrete
0.02
20.04
0.0048
Wall
Old english red bricks
0.03
3.03
0.0909
Wall
Glass
0.2
18.92
3.784
Ceiling
Concrete
0.02
20.04
0.4008
Door
Glass
0.2
3.46
0.692
Furniture
Polished wood
0.03
0.14
0.0042
0.46
0
0
Total Absorption, A
4.98
Human
RT= (0.16 x V) / A = (0.16 x 72.14)/4.98 = 2.32s
Material absorption coefficient in 2000Hz at peak hour: Building Element
Material
Absorption Coefficient, a (2000Hz)
Area, S/m2
Sxa
Floor
Polished concrete
0.02
20.04
0.4008
Wall
Old english red bricks
0.05
3.03
0.1515
Wall
Glass
0.07
18.92
1.3244
Ceiling
Concrete
0.02
20.04
0.4008
Door
Glass
0.07
3.46
0.2422
Furniture
Polished wood
0.1
0.14
0.014
0.51
0
0
Total Absorption, A
2.53
Human
RT= (0.16 x V) / A = (0.16 x 72.14)/2.53 = 4.56s
Zone 2: Outdoor dining area
Volume, V= 11.3X3.6= 40.68M2 Material absorption coefficient in 125Hz at peak hour: Building Element
Material
Absorption Coefficient, a (125Hz)
Area, S (m2)
Sxa
Floor
Polished concrete
0.1
40.68
4.07
Wall
Glass
0.18
10.80
1.94
Ceiling
Painted steel
0.34
40.68
13.83
Door
Glass
0.3
2.97
0.89
Furniture
Polished wood
0.02
1.4
0.03
0.21 per person
0.14
0
Total Absorption, A
20.76
Human
RT= (0.16 x V) / A = (0.16 x 40.68)/20.76 = 0.31s
Material absorption coefficient in 500Hz at peak hour: Building Element
Material
Absorption Coefficient, a (500Hz)
Area, S (m2)
Sxa
Floor
Polished concrete
0.1
40.68
4.07
Wall
Glass
0.18
10.80
1.94
Ceiling
Painted steel
0.36
40.68
14.64
Door
Glass
0.3
2.97
1.78
Furniture
Polished wood
0.02
1.4
0.03
0.21 per person
0.14
0
Total Absorption, A
22.46
Human
RT= (0.16 x V) / A = (0.16 x 40.68)/22.46 = 0.29s
Material absorption coefficient in 2000Hz at peak hour: Building Element
Material
Absorption Coefficient, a (2000Hz)
Area, S (m2)
Sxa
Floor
Polished concrete
0.1
40.68
4.07
Wall
Glass
0.18
10.80
1.94
Ceiling
Painted steel
0.17
40.68
6.92
Door
Glass
0.3
2.97
0.89
Furniture
Polished wood
0.02
1.4
0.03
0.21 per person
0.14
0
Total Absorption, A
13.85
Human
RT= (0.16 x V) / A = (0.16 x 40.68)/13.85 = 0.47s
Zone 3 : Indoor dining area
Volume, V= 65.13X3.6= 234.47M2 Material absorption coefficient in 125Hz at peak hour: Building Element
Material
Absorption Coefficient, a (125Hz)
Area, S (m2)
Sxa
Floor
Polished concrete
0.1
65.13
6.51
Wall
Concrete
0.1
16.20
1.62
Wall
Glass
0.18
103.18
18.57
Ceiling
Painted steel
0.34
65.13
22.14
Door
Glass
0.3
13.25
3.98
Furniture
Polished wood
0.02
11.2
0.22
0.21 per person
0.14
0
Total Absorption, A
53.04
Human
RT= (0.16 x V) / A = (0.16 x 234.47)/53.04 = 0.71s
Material absorption coefficient in 500Hz at peak hour: Building Element
Material
Absorption Coefficient, a (500Hz)
Area, S (m2)
Sxa
Floor
Polished concrete
0.1
65.13
6.51
Wall
Concrete
0.02
16.20
0.32
Wall
Glass
0.18
103.18
18.57
Ceiling
Painted steel
0.36
65.13
23.45
Door
Glass
0.3
13.25
3.98
Furniture
Polished wood
0.02
11.2
0.22
0.21 per person
0.14
0
Total Absorption, A
53.05
Human
RT= (0.16 x V) / A = (0.16 x 234.47)/53.05 = 0.71s
Material absorption coefficient in 2000Hz at peak hour: Building Element
Material
Absorption Coefficient, a (2000Hz)
Area, S (m2)
Sxa
Floor
Polished concrete
0.1
65.13
6.51
Wall
Concrete
0.02
16.20
0.32
Wall
Glass
0.18
103.18
18.57
Ceiling
Painted steel
0.17
65.13
11.07
Door
Glass
0.3
13.25
3.98
Furniture
Polished wood
0.02
11.2
0.22
0.21 per person
0.14
0
Total Absorption, A
40.67
Human
RT= (0.16 x V) / A = (0.16 x 234.47)/40.67 = 0.92s
First Floor Zone 4: Outdoor Dining Area
Volume, V= 10.58X3.3= 34.91M2 Material absorption coefficient in 125Hz at peak hour: Building Element
Material
Absorption Coefficient, a (125Hz)
Area, S (m2)
Sxa
Floor
Painted Steel Plate
0.34
10.58
3.60
Wall
Glass
0.2
10.13
2.03
Ceiling
Polycarbonate
0.3
10.58
3.17
Door
Glass
0.07
3.3
0.23
Furniture
Polished wood
0.03
1.4
0.04
0.21 per person
0
0
Total Absorption, A
9.07
Human
RT= (0.16 x V) / A = (0.16 x 34.91)/9.07 = 0.62s
Material absorption coefficient in 500Hz at peak hour: Building Element
Material
Absorption Coefficient, a (500Hz)
Area, S/m2
Sxa
Floor
Painted Steel Plate
0.36
10.58
3.81
Wall
Glass
0.18
10.13
1.82
Ceiling
Polycarbonate
0.85
10.58
8.99
Door
Glass
0.18
3.3
0.59
Furniture
Polished wood
0.02
1.4
0.03
0.21
0
0
Total Absorption, A
15.24
Human
RT= (0.16 x V) / A = (0.16 x 34.91)/15.24 = 0.37 s
Material absorption coefficient in 2000Hz at peak hour: Building Element
Material
Absorption Coefficient, a (2000Hz)
Area, S/m2
Sxa
Floor
Painted Steel Plate
0.17
10.58
1.80
Wall
Glass
0.07
10.13
0.71
Ceiling
Polycarbonate
0.7
10.58
7.41
Door
Glass
0.3
3.3
0.99
Furniture
Polished wood
0.02
1.4
0.03
0.21
0
0
Total Absorption, A
10.94
Human
RT= (0.16 x V) / A = (0.16 x 34.91)/10.94 = 0.51s
Zone 5: Indoor Dining Area
Volume, V= 41.49X3.3= 136.92M2 Material absorption coefficient in 125Hz at peak hour: Building Element
Material
Absorption Coefficient, a (125Hz)
Area, S (m2)
Sxa
Floor
Painted Steel Plate
0.34
41.49
14.11
Wall
Glass
0.2
80.59
16.12
Wall
Concrete
0.1
32.80
3.28
Ceiling
Polycarbonate
0.3
41.49
12.45
Door
Glass
0.07
10.31
0.72
Furniture
Polished wood
0.03
9.8
0.29
0.21 per person
0
0
Total Absorption, A
46.97
Human
RT= (0.16 x V) / A = (0.16 x 136.92)/46.97 = 0.47s
Material absorption coefficient in 500Hz at peak hour: Building Element
Material
Absorption Coefficient, a (500Hz)
Area, S/m2
Sxa
Floor
Painted Steel Plate
0.36
41.49
14.94
Wall
Glass
0.18
80.59
14.51
Wall
Concrete
0.02
32.80
0.66
Ceiling
Polycarbonate
0.85
41.49
35.27
Door
Glass
0.18
10.31
1.86
Furniture
Polished wood
0.02
9.8
0.20
0.21
0
0
Total Absorption, A
67.44
Human
RT= (0.16 x V) / A = (0.16 x 136.92)/67.44 = 0.32 s
Material absorption coefficient in 2000Hz at peak hour:
Building Element
Material
Absorption Coefficient, a (2000Hz)
Area, S/m2
Sxa
Floor
Painted Steel Plate
0.17
41.49
7.05
Wall
Glass
0.07
80.59
5.64
Wall
Concrete
0.02
32.80
0.66
Ceiling
Polycarbonate
0.7
41.49
29.04
Door
Glass
0.3
10.31
3.09
Furniture
Polished wood
0.02
9.8
0.20
0.21
0
0
Total Absorption, A
45.68
Human
RT= (0.16 x V) / A = (0.16 x 136.92)/45.68 = 0.48 s
Zone 6 : Balcony
Volume, V= 15.66X3.3= 51.68M2 Material absorption coefficient in 125Hz at peak hour: Building Element
Material
Absorption Coefficient, a (125Hz)
Area, S (m2)
Sxa
Floor
Painted Steel Plate
0.34
51.68
17.57
Wall
Glass
0.2
10.43
2.09
Wall
Concrete
0.1
23.69
2.37
Ceiling
Polycarbonate
0.3
51.68
15.50
Door
Glass
0.07
3.70
0.26
Furniture
Polished wood
0.03
0
0
0.21 per person
0
0
Total Absorption, A
37.79
Human
RT= (0.16 x V) / A = (0.16 x 51.68)/37.79 = 0.22s
Material absorption coefficient in 500Hz at peak hour: Building Element
Material
Absorption Coefficient, a (500Hz)
Area, S/m2
Sxa
Floor
Painted Steel Plate
0.36
51.68
18.60
Wall
Glass
0.18
10.43
1.88
Wall
Concrete
0.02
23.69
0.47
Ceiling
Polycarbonate
0.85
51.68
43.93
Door
Glass
0.18
3.70
0.67
Furniture
Polished wood
0.02
51.68
1.03
0.21
0
0
Total Absorption, A
66.58
Human
RT= (0.16 x V) / A = (0.16 x 51.68)/66.58 = 0.12s
Material absorption coefficient in 2000Hz at peak hour: Building Element
Material
Absorption Coefficient, a (2000Hz)
Area, S/m2
Sxa
Floor
Painted Steel Plate
0.17
51.68
8.79
Wall
Glass
0.07
10.43
0.73
Wall
Concrete
0.02
23.69
0.47
Ceiling
Polycarbonate
0.7
51.68
36.18
Door
Glass
0.3
3.70
1.11
Furniture
Polished wood
0.02
51.68
1.03
0.21
0
0
Total Absorption, A
47.25
Human
RT= (0.16 x V) / A = (0.16 x 51.68)/47.25 = 0.18 s
5.1.4 Sound Pressure Level, (SPL) The sound pressure level is the average sound level at a space. The sound pressure level (SPL) formula is shown at below: Combined SPL = 10 log (l/lref), where lref = 1 × 10-12 Sound Level Measurement Power Addition Method for dB addition: The Formula: L = 10 log (I / Io (ref)) Where I = sound power (intensity) (Watts) Io = reference power (1 x 10-12 Watts) Ground Floor Zone 1: Bar Area
Non-Peak hour Highest reading: 71dB Use the formula, L = 10 log (lH/lref), 71 = 10 log10 (IH/ 1 × 10-12) IH = (107.1) (1 × 10-12) =1.26x 10-5 Lowest reading: 67dB Use the formula, L = 10 log (lL/lref), 67 = 10 log10 (IL/ 1 x 10-12) IL = (10 6.7) (1 x 10-12) = 5.01× 10-6 Total Intensities, I= (1.26× 10-5) + (5.01× 10-6) = 1.76 × 10-5 Using the formula combined SPL = 10 log (l/lref), Combined SPL = 10 log × [(1.76× 10-5) ÷ (1 × 10-12)] Combined SPL at bar area during non-peak hour= 72.46 dB
Peak hour Highest reading: 77dB Use the formula, L = 10 log (lH/lref), 77 = 10 log10 (IH/ 1 × 10-12) IH = (107.7) (1 × 10-12) =5.02 x 10-5 Lowest reading: 65dB Use the formula, L = 10 log (lL/lref), 65 = 10 log10 (IL/ 1 x 10-12) IL = (10 6.5) (1 x 10-12) = 3.16 × 10-6 Total Intensities, I= (5.02 × 10-5) + (3.16 × 10-6) = 5.34 × 10-5 Using the formula combined SPL = 10 log (l/lref), Combined SPL = 10 log × [(5.34 × 10-5) ÷ (1 × 10-12)] Combined SPL at bar area during peak hour= 77.28 dB Zone 2: outdoor dining
Peak hour Highest reading: 70dB Use the formula, L = 10 log (lH/lref), 70 = 10 log10 (IH/ 1 × 10-12) IH = (107.0) (1 × 10-12) =1 x 10-5 Lowest reading: 57dB Use the formula, L = 10 log (lL/lref), 57 = 10 log10 (IL/ 1 x 10-12) IL = (10 5.7) (1 x 10-12) = 5.01 × 10-7 Total Intensities, I= (1× 10-5) + (5.01 × 10-7) = 1.50 × 10-5 Using the formula combined SPL = 10 log (l/lref), Combined SPL = 10 log × [(1.50 × 10-5) ÷ (1 × 10-12)] Combined SPL at bar area during peak hour= 71.76 dB
Non-peak hour Highest reading: 68dB Use the formula, L = 10 log (lH/lref), 68 = 10 log10 (IH/ 1 × 10-12) IH = (106.8) (1 × 10-12) =6.31 x 10-6 Lowest reading: 51dB Use the formula, L = 10 log (lL/lref), 51 = 10 log10 (IL/ 1 x 10-12) IL = (10 5.1) (1 x 10-12) = 1.26 × 10-7 Total Intensities, I= (1× 10-5) + (5.01 × 10-6) = 1.50 × 10-5 Using the formula combined SPL = 10 log (l/lref), Combined SPL = 10 log × [(1.50 × 10-5) ÷ (1 × 10-12)] Combined SPL at bar area during peak hour= 71.76 dB Zone 3: indoor dining area
Non-peak hour Highest reading: 71 dB Use the formula, L = 10 log (lH/lref), 71 = 10 log10 (IH/ 1 × 10-12) IH = (107.7) (1 × 10-12) =5.01 x 10-5 Lowest reading: 65 dB Use the formula, L = 10 log (lL/lref), 65 = 10 log10 (IL/ 1 x 10-12) IL = (10 6.5) (1 x 10-12) = 3.16 × 10-6
Total Intensities, I= (1× 10-5) + (3.16 × 10-6) = 1.32 × 10-5 Using the formula combined SPL = 10 log (l/lref), Combined SPL = 10 log × [(1.32 × 10-5) ÷ (1 × 10-12)] Combined SPL at bar area during peak hour= 71.19 dB Peak hour Highest reading: 77dB Use the formula, L = 10 log (lH/lref), 77 = 10 log10 (IH/ 1 × 10-12) IH = (107.7) (1 × 10-12) =5.01 x 10-5 Lowest reading: 65dB Use the formula, L = 10 log (lL/lref), 65 = 10 log10 (IL/ 1 x 10-12) IL = (10 6.5) (1 x 10-12) = 3.16 × 10-6 Total Intensities, I= (5.01× 10-5) + (3.16 × 10-6) = 5.33 × 10-5 Using the formula combined SPL = 10 log (l/lref), Combined SPL = 10 log × [(5.33 × 10-5) ÷ (1 × 10-12)] Combined SPL at bar area during peak hour= 77.27 dB
First Floor Zone 4: Outdoor Dining Area
Non-Peak hour Highest Reading: 55dB Use the formula, L = 10 log (lH/lref), 55 = 10 log10 (IH/ 1 × 10-12) IH = (105.5) (1 × 10-12) =3.16 x 10-7 Lowest reading: 54dB Use the formula, L = 10 log (lL/lref), 54 = 10 log10 (IL/ 1 x 10-12) IL = (10 5.4) (1 x 10-12) = 2.51 × 10-7 Total Intensities, I= (3.16 × 10-7) + (2.51 × 10-7) = 5.67 × 10-7 Using the formula combined SPL = 10 log (l/lref), Combined SPL = 10 log × [(5.67 × 10-7) ÷ (1 × 10-12)] Combined SPL at bar area during non-peak hour= 57.54 dB Peak hour Highest reading: 62dB Use the formula, L = 10 log (lH/lref), 62 = 10 log10 (IH/ 1 × 10-12) IH = (106.2) (1 × 10-12) =1.58 x 10-6 Lowest reading: 56dB Use the formula, L = 10 log (lL/lref), 56 = 10 log10 (IL/ 1 x 10-12) IL = (10 5.6) (1 x 10-12) = 3.98× 10-7
Total Intensities, I= (1.58× 10-6) + (3.98× 10-7) = 1.98× 10-6 Using the formula combined SPL = 10 log (l/lref), Combined SPL = 10 log × [(1.98× 10-6) ÷ (1 × 10-12)] Combined SPL at bar area during peak hour= 62.96 dB
Zone 5: Indoor Dining Area
Non-Peak hour Highest reading: 63dB Use the formula, L = 10 log (lH/lref), 63 = 10 log10 (IH/ 1 × 10-12) IH = (106.3) (1 × 10-12) = 2.0 x 10-6 Lowest reading: 72dB Use the formula, L = 10 log (lL/lref), 72 = 10 log10 (IL/ 1 x 10-12) IL = (10 7.2) (1 x 10-12) = 1.58 × 10-5 Total Intensities, I= (2.0 × 10-6) + (1.58 × 10-5) = 1.78 × 10-7 Using the formula combined SPL = 10 log (l/lref), Combined SPL = 10 log × [(1.78 × 10-7) ÷ (1 × 10-12)] Combined SPL at bar area during non-peak hour= 72.51 dB
Peak hour Highest reading: 80dB Use the formula, L = 10 log (lH/lref), 80 = 10 log10 (IH/ 1 × 10-12) IH = (108.0) (1 × 10-12) =1.0 x 10-4 Lowest reading: 67dB Use the formula, L = 10 log (lL/lref), 67 = 10 log10 (IL/ 1 x 10-12) IL = (10 6.7) (1 x 10-12) = 5.01× 10-6 Total Intensities, I= (1.0 × 10-4) + (5.01 × 10-6) = 1.05× 10-4 Using the formula combined SPL = 10 log (l/lref), Combined SPL = 10 log × [(1.05× 10-4) ÷ (1 × 10-12)] Combined SPL at bar area during peak hour= 80.21 dB
Zone 6: Balcony
Non-Peak hour Highest reading: 81dB Use the formula, L = 10 log (lH/lref), 81 = 10 log10 (IH/ 1 × 10-12) IH = (108.1) (1 × 10-12) = 1.26 x 10-4 Lowest reading: 76dB Use the formula, L = 10 log (lL/lref), 76 = 10 log10 (IL/ 1 x 10-12) IL = (10 7.6) (1 x 10-12) = 3.98 × 10-5
Total Intensities, I= (1.26 × 10-4) + (3.98 × 10-5) = 1.66 × 10-4 Using the formula combined SPL = 10 log (l/lref), Combined SPL = 10 log × [(1.66 × 10-4) ÷ (1 × 10-12)] Combined SPL at bar area during non-peak hour= 82.20 dB Peak hour Highest reading: 81dB Use the formula, L = 10 log (lH/lref), 81 = 10 log10 (IH/ 1 × 10-12) IH = (108.1) (1 × 10-12) =1.26 x 10-4 Lowest reading: 78dB Use the formula, L = 10 log (lL/lref), 78 = 10 log10 (IL/ 1 x 10-12) IL = (10 7.8) (1 x 10-12) = 6.31× 10-5 Total Intensities, I= (1.26 × 10-4) + (6.31 × 10-5) = 1.89× 10-4 Using the formula combined SPL = 10 log (l/lref), Combined SPL = 10 log × [(1.89× 10-4) ÷ (1 × 10-12)] Combined SPL at bar area during peak hour= 82.76 dB
Sound Reduction Index (SRI) Calculation Using Formula: When T = transmission loss TL = 10 log10 1/Tav Tav = (S1 x Tc1 + S2 x T2 + Sn x Tn) / Total Surface Area Overall SRI = 10log10 1/T Tcn = Transmission coefficient of material Sn = Surface area of material n Zone 5 & Zone 6
Wall: Glass panel SRI wall: Glass panel = 32dB Sn = 15.79 m² Calculation: 32 = 10log (1/T) T = 0.00063 Sn x T wall = 15.79 × 0.00063 = 0.0099 Surface
Area, m2 (SN)
SRI (dB)
Tcn
Sn x Tn
Wall : Glass Panel
15.79
32
0.00063
0.0099
T average = (Sn x Tn)/ Total Surface Area = (0.0099)/15.79 = 0.0006 1/Tav = 1594.95
SRI overall = 10 × log (1/Tav) = 10 × log (1594.95) = 32.03dB
Conclusion Zone 5 combine SPL is 72.51dB – 81.21dB, Zone 6 combine SPL is 82.20dB – 82.76dB. After the deduction on the transmission loss after sound pass through the wall, 32.03dB Using the highest value of SPL of Zone 5, 81.21dB – 32.03dB = 50.18dB Based on the calculation above, the sound transmission lost in the wall between balcony and first floor indoor dining area is poor due to the condenser located at the balcony. The sound transmission loss of the wall is 32.03dB which means the sound transmission is reduced by 32.03dB from indoor dining area at first floor,82.76dB to balcony which is left with 50.18dB. The calculation is proved by the average SPL of both zones to calculate the transmission loss of the wall.
6.0 Conclusion This assignment has been a great journey with full of rich knowledge and experiences to study the basic details of a space and its elements. Due to this assignment, we get to understand better the daylighting and acoustic characteristics and requirements in a cafeteria which we have chosen. We were required to analyze the chosen café, Grey Sky Morning Café, in terms of its lighting and acoustics. Thus, we have visited and recorded the lighting and acoustics of the café at different time slots on different days. Throughout the project, we are able to document and do critical analysis on the data that we have recorded in the café and produced a full report based on the lighting and acoustic characteristics of the café.
7.0 References
Department of Standards Malaysia. (2007). Malaysian standard ms1525. (1st ed.). Malaysia: Pertubuhan Akitek Malaysia. Hyperphysics.phy-astr.gsu.edu,. (2014). Reverberation Time. Retrieved 23 October 2014, from http://hyperphysics.phy-astr.gsu.edu/hbase/acoustic/revtim.html Lighting.philips.com.my,. (2014). Philips Lighting Malaysia - LED & Conventional Lighting Solutions. Retrieved 23 October 2014, from http://www.lighting.philips.com.my/ Britt, N. (2010). Acoustic. Brentwood, TN: Sparrow Records.
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