Bb science project 2
Transcript of Bb science project 2
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Content
1.0 Lighting
1.1 Daylight Factor Pg. 2-6 1.2 Artificial Lighting Pg. 7-12 1.3 PSALI Pg.13-18
2.0 Acoustic
2.1 Reverberation Time Pg. 19-23 2.2 Sound Transmission Loss Pg. 23-27
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1.0 Lighting 1.1 Daylight Factor
Daylight Factor is the ratio between the actual illuminance at a point inside a room
and the illuminance possible from an unobstructed hemisphere of the same sky.
Unit: percentage
Daylight factor can be expressed by the following formula
𝐷𝐹 =𝐸𝑖𝐸𝑜 ×100
Where
DF= daylight factor at a chosen reference point in the room (per cent)
Ei= illuminance at the reference point (lx)
Eo= illuminance at the point if the sky was unobstructed (lx)
Table 1 Recommended Daylight Factor by MS1525
Space 1: Book Collection Area
DF, % Distribution >6 Very bright with thermal & glare problem 3~6 Bright 1~3 Average 0~1 Dark
Figure 1 Book Collection Area at ground floor plan
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Daylight Factor
Using the daylight factor formula, illuminance of the book collection area can be calculated.
𝐷𝐹 =𝐸𝑖𝐸𝑜 ×100
22.34 =𝐸𝑖
32000 ×100
𝐸𝑖 =22.34100 ×32000
Ei = 7148.8 lux
Floor Area/ m² 43.74 Area of façade exposed to sunlight/ m² 54.00 Area of skylight/ m² 43.74 Exposed Façade & Skylight Area to Floor Area Ratio
54 + 43.7443.74
=22.34%
Figure 2 Light Contour of Book Collection Area at ground floor
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Table 2 Typical Daylight Levels
Location Average Daylight Factor Minimum daylight factor Surface General Ofiice 5 2 Desks Classroom 5 2 Desks Entrance Hall 2 0.6 Working Plane Library 5 1.5 Tables Drawing Office 5 2.5 Boards Sports Day 5 3.5 Working Plane
According to the result calculated, total daylight factor in book collection area is about
22.34% which is way higher than the expected daylight levels of 1.5%-5%. This is due to the
location at the airwell, exposed to skylight. Sunlight exposure is not recommended in area
where books are stored, therefore, along the airwell, louvers are installed to provide shadows
casted on books.
Space 2: Café Area
Floor Area/ m² 50.75 Area of façade exposed to sunlight/ m² 32.96+10.8=43.76 Area of skylight/ m² 0
Figure 3 Cafes at Ground Floor
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𝐷𝐹 =𝐸𝑖𝐸𝑜 ×100
8.6 =𝐸𝑖
32000 ×100
𝐸𝑖 =8.6100 ×32000
Ei = 2752 lux The result showed daylgith factor at the café area is relatively low compare to the book
collection area which is 8.6%. This also can be seen via the light contour diagram above shows
the darker colour (red) shows the lower light intensity. However,, it is still higher than the
average daylight factor that a café need. The resukt is still acceptable as there’s no paperwork
or activities that require concentration. The café is designed at the back of the lot because of
Exposed Façade & Skylight Area to Floor Area Ratio
43.7650.75
=0.86 =8.6%
Figure 4 Light Contour of Cafe at ground floor
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the existence of trees canopy at the back which would be able to provide shades to solve the
high daylight level of the café. Besides, there’s landscape located at the area expose to
sunlight to lower down the light intensity, preventing issues like glare.
Figure 5 Landscape Area located at the facade exposed to sunlight
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1.2 Artificial Lighting Space 1: Digital Room Standard IL luminance: 300 lux
Type of light bulb Linear 4ft T8 Fluorescent Light Bulb
Product Model Philips model no: # 422949
Rated luminous flux 2750lm Colour rendering Index 82
Normal Life (hours) 30,000 Wattage Range (W) 32
Figure 6 Digital Rooms at Forth Floor
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Colour Temperature, K 6500 Colour Designation Daylight Deluxe
Dimension of room (L X W)(m) 7.5m X 10.74 Total Floor Area, A (m²) 80.55 m^2 Height of Ceiling 2.7m Type of Lighting Fixture T8 Fluorescent Light Bulb Lumen of Lighting Fixture, F (lm) 2750 Height of Luminaire (m) 2.7 Height of work level (m) 0.95 Mounting height (m) 1.75 Reflection Factors Ceiling: 0.7 Wall: 0.5 Floor: 0.2 Room Index, RI (K)
= 2.5
Utilisation Factor, UF 0.48 Maintenance Factor, MF 0.8 Number of lamps required – N *MS1525 Recommended Computer Room Illumination Level – 300 Lux
=22.88 ⋍23 Double Fluorescent Lamp fitting is used, therefore, half Number of luminance is included in spacing calculation.
Spacing to Height Ratio (SHR)
SHR= 1/Hm x 𝐴/𝑁
=1/1.75 x 80.55/12 =1.48
SHR=!
!.!" = 1.48
S= 1.75 x 1.48 =2.59m ⋍3m
Fittings Layout By approximately (m)
Fittings required along 10.74 wall 12/3m=4 rows Number of lamps required in each row =total number of lights required / number of rows =12/4 = 3
𝑁 = !"" ! !".!!(!"#$ ! !.!"! !.!)
𝑁 =
𝐸 𝑥 𝐴(𝐹 𝑥 𝑈𝐹 𝑥 𝑀𝐹)
𝑅𝐼 = 𝐿 𝑥 𝑊
(𝐿 +𝑊) 𝑥 𝐻 𝑅𝐼 =
7.5𝑋 10.747.5+ 10.74 𝑋1.75
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Total of 23 fluorescent lights is needed to light up the digital room to 300 lux. Due to
the limited length of the room, the fluorescent is arranged in pairs to achieve the arrangement
Spacing along 7.5wall 7.5/3 =2.5m
Figure 7 Fluorescent Lighting Layout of Digital Room
Figure 9 Daylight light contour of Digital Room Figure 8 Artificial light contour of Digital Room
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of 4rows with 3 light fittings, to form total of 24 lights with spacing of 2.5m. With the even
distribution of light, the users would feel comfortable with their eyes staring at the computer
screen for long hours.
Space 2: Study Room Standard IL luminance: 300 lux
Type of light bulb LED slimline Dimmable Downlight
Product Model LEDlux Comparda 32E450TM Rated luminous flux 3200 lm
Colour rendering Index - Normal Life (hours) - Wattage Range (W) 40
Colour Temperature, K - Colour Designation Warm White
Figure 10 Study Room at Second Floor
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Dimension of room (L X W)(m) 5m X 15.54m Total Floor Area, A (m²) 77.7 m^2 Height of Ceiling 2.7m Type of Lighting Fixture LED Downlight Lumen of Lighting Fixture, F (lm) 3200 Height of Luminaire (m) 2.7 Height of work level (m) 0.95 Mounting height (m) 1.75 Reflection Factors Ceiling: 0.7 Wall: 0.5 Floor: 0.2 Room Index, RI (K)
= 2.16
Utilisation Factor, UF 0.65 Maintenance Factor, MF 0.8 Number of lamps required – N *MS1525 Recommended Study Room Illumination Level – 300 Lux
=14
Spacing to Height Ratio (SHR)
SHR= 1/Hm x 𝐴/𝑁
=1/1.75 x 77.7/14 =1.35m
SHR=!
!.!" = 1.35
S= 1.75 x 1.35 =2.35m ⋍2.5m
𝑁 = 𝐸 𝑥 𝐴
(𝐹 𝑥 𝑈𝐹 𝑥 𝑀𝐹)
𝑅𝐼 = 𝐿 𝑥 𝑊
(𝐿 +𝑊) 𝑥 𝐻 𝑅𝐼 =
5.0𝑋 15.545.0+ 15.54 𝑋1.75
𝑁 = !"" ! !!.!(!"## ! !.!"! !.!)
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Total of 14 LED down lights are needed to achieve 300 lux for the study room. The
light contour diagrams show the corner area relatively low in light intensity; therefore, most of
the furniture is arranged in the center to ensure students to study with sufficient light.
Fittings Layout By approximately (m)
Fittings required along 15.54m wall 14/2.5m=5.6 rows ⋍6rows Number of lamps required in each row =total number of lights required / number of rows =14/6 = 2.3 ⋍3 Spacing along 5m wall 5m/3 =1.67m
Figure 11 Down Light Layouts at Study Room
Figure 12 Daylight light contour of Study Room
Figure 13 Artificial Light Contours at Study Room
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1.3 PSALI – Permanent Supplementary Artificial Lighting of Interiors Space 1: Reading Area (300 lux)
Type of fixture LED Wrapped around Surface Mounted Type of light bulb
Product Model PLT 55029 Rated luminous flux 2900lm
Colour rendering Index - Normal Life (hours) - Wattage Range (W) 30
Colour Temperature, K - Colour Designation White
Figure 14 Reading Areas at Second Floor
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Dimension of room (L X W)(m) 3.7m X 12.44m Total Floor Area, A (m²) 46 m^2 Height of Ceiling 2.7 Type of Lighting Fixture LED Wrapped around Lumen of Lighting Fixture, F (lm) 2900 Height of Luminaire (m) 2.7 Height of work level (m) 0.95 Mounting height (m) 1.75 Reflection Factors Ceiling: 0.7 Wall: 0.5 Floor: 0.2 Room Index, RI (K)
= 1.63
Utilisation Factor, UF 0.43 Maintenance Factor, MF 0.8 Number of lamps required – N *MS1525 Recommended Reading Illumination Level – 300 Lux = 19.2 ⋍ 19
Spacing to Height Ratio (SHR)
SHR= 1/Hm x 𝐴/𝑁
=1/1.75x 64/19 =1.05
SHR=!
!.!" = 1.05
S= 1.75 x 1.05 =1.8
Fittings Layout By approximately (m)
Fittings required along 12.44m wall 19/1.8 =10.55rows ⋍11 rows Number of lamps required in each row =total number of lights required / number of rows =19/11 =1.7 ⋍2 Spacing along 3.7mwall 3.7/2 =1.85m
𝑅𝐼 = 𝐿 𝑥 𝑊
(𝐿 +𝑊) 𝑥 𝐻 𝑅𝐼 =
3.7 𝑋 12.443.7+ 12.44 1.75
𝑁 = 𝐸 𝑥 𝐴
(𝐹 𝑥 𝑈𝐹 𝑥 𝑀𝐹)
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There are two switches in the reading area. First switch is controlling the row that near
the glass façade and the other switch is controlling the row facing the air well. The light near
the air well is higher than the one near the glass façade, due to the north orientation of the
building causing the other part to be darker. Therefore, glass is used for the façade material
and is placed at the second floor to prevent neighboring building from blocking the sunlight.
Figure 15 Fluorescent Lighting Layouts at Reading Room
Figure 16 Daylight Light Contour at Reading Area
Figure 17 Artificial Light Contours at Reading Area
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Space 2: Café Area (200 lux)
Type of fixture Dimmable LED Pendant Type of light bulb
Product Model SKU 020614 Rated luminous flux 2000lm
Colour rendering Index - Normal Life (hours) - Wattage Range (W) 29
Colour Temperature, K - Colour Designation Warm White
Suspension (m) 1000
Dimension of room (L X W)(m) 5.1m X 9.26m Total Floor Area, A (m²) 47.22 m^2 Height of Ceiling 2.7
Figure 18 Cafe Areas at Ground Floor
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Type of Lighting Fixture LED Pendant Lumen of Lighting Fixture, F (lm) 2000 Height of Luminaire (m) 1.70 Height of work level (m) 0.95 Mounting height (m) 0.75 Reflection Factors Ceiling: 0.7 Wall: 0.5 Floor: 0.2 Room Index, RI (K)
= 4.38
Utilisation Factor, UF 0.5 Maintenance Factor, MF 0.8 Number of lamps required – N *MS1525 Recommended Reading Illumination Level – 300 Lux = 11.8 ⋍12
Spacing to Height Ratio (SHR)
SHR= 1/Hm x 𝐴/𝑁
=1/0.75x 47.22/12 =2.64m
SHR=!
!.!" = 2.64
S= 0.75 x 2.64 =1.98 ⋍2m
Fittings Layout By approximately (m)
Fittings required along 12.44m wall 12/2m = 6rows Number of lamps required in each row =total number of lights required / number of rows =12/6 =2 Spacing along 5.1mwall 5.1/2 =2.55m
𝑅𝐼 = 𝐿 𝑥 𝑊
(𝐿 +𝑊) 𝑥 𝐻 𝑅𝐼 =
5.1 𝑋 9.265.1+ 9.26 0.75
𝑁 = 𝐸 𝑥 𝐴
(𝐹 𝑥 𝑈𝐹 𝑥 𝑀𝐹)
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The café area consists of three switches. One is controlling the lighting near the
counter area. For food display purpose, the lights need to be switched on throughout the day to
increase food appearance and thus attract people attention. The other switch is located near
the lounge area near the back façade while the other is near the air well seating. It can be
switch off during daytime to save electricity due to the relatively high light intensity as shown in
the light contour diagram.
Figure 19 LED Pendant Light Fitting at Cafe Area
Figure 20 Daylight Light Contour at Cafe Area Figure 21 Artificial Light Contours at Cafe Area
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2. Acoustic 2.1 Reverberation Time (RT)
Reverberation time is defined as the length of time required for the sound to decay
60 decibels from its initial level. The desirable reverberation time will vary depending on
the function of the room. Higher reverberation time aids the sound to carry and add more
characters to the acoustic. Too much reverberation time would have caused the sound to
lost its clarity in a confusing echo.
Reverberation time is calculated as the formula:
Reverberation Time, RT = (0.16xV)/A
To use this formula, the volume of the room, surface area of each material of the room,
and absorption coefficient of those materials must be known. Absorption coefficient is
measured in specialized laboratories rating from 0-1 decimal.
Space 1: Meeting Room Standard Reverberation time: 0.6-1s
Total Floor Area (m^2) 29 Volume (m^3) 872 Occupancy 19 Room Height (m) 3.0
Material Absorption Coefficient at 500 Hz Building Component
Material Area (m^2) Absorption Coefficient, a
Sound Absorption, Sa
Figure 22 Meeting Room at Forth Floor
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Wall Brick wall with plaster finish
10.74 0.02 0.215
Glass wall (Double Glazing 2-3mm glass with 10mm glass gap)
56.76 0.03 1.703
Floor Carpet 29.00 0.25 7.250 Ceiling Plywood
(Plywood 5mm, on battens 50mm airspace filled with glass wool)
29.00 0.20 5.800
People - 9 0.45 4.050 Furniture Leather covered 3.60 0.58 2.088 Total Absorption, A 21.106 Reverberation Time, RT = (0.16xV)/A = (0.16x87)/21.106 =0.65s
Material Absorption Coefficient at 2000 Hz Building Component
Material Area (m^2) Absorption Coefficient, a
Sound Absorption, Sa
Wall Brick wall with plaster finish
10.74 0.05 0.538
Glass wall (Double Glazing 2-3mm glass with 10mm glass gap)
56.76 0.02 1.135
Floor Carpet 29.00 0.30 8.700 Ceiling Plywood
(Plywood 5mm, on battens 50mm airspace filled with glass wool)
29.00 0.05 1.450
People - 9 0.45 4.05 Furniture Leather covered 3.60 0.58 2.088 Total Absorption, A 17.96 Reverberation Time, RT = (0.16xV)/A = (0.16x87)/17.96 =0.78s
Recommended reverberation time for meeting room or conference room is set
between 0.6-1s. The result shown in 500Hz condition, RT for the meeting room is 0.65s while
2000Hz is 0.78s. This shows that the acoustic of the room is well controlled. This is due to the
placement of acoustic panel as the ceiling with 50mm of air space. Sound is trapped and lost
its energy to reflect back. However, even if the reverberation time is optimally controlled,
reflection of sound from the adjacent walls can create issues like flutter echo or standing wave.
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Ideally, one side of the wall is covered with acoustic absorptive material. A desirable sound
level plays an essential role in making a presentation a success.
Space 2: Study Area Standard Reverberation time: 0.6-0.7s Total Floor Area (m^2) 74.90 Volume (m^3) 224.70 Occupancy 20 Room Height (m) 3.0
Wood Flooring without carpeted Material Absorption Coefficient at 500 Hz Building Component
Material Area (m^2) Absorption Coefficient, a
Sound Absorption, Sa
Wall Brick wall with plaster finish
12.90 0.02 0.258
Glass wall (Double Glazing 2-3mm glass with 10mm glass gap)
102.67 0.03 3.080
Floor Timber 74.90 0.10 7.490 Ceiling Plywood
(Plywood 5mm, on battens 50mm airspace filled with glass wool)
74.90 0.20 14.980
People - 20 0.45 9.00 Furniture Leather covered 20.00 0.58 11.60 Total Absorption, A 46.408 Reverberation Time, RT = (0.16xV)/A = (0.16x 224.70)/46.408 =0.77s
Figure 23 Study Areas at Second Floor
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Wood Flooring without carpeted Material Absorption Coefficient at 2000 Hz Building Component
Material Area (m^2) Absorption Coefficient, a
Sound Absorption, Sa
Wall Brick wall with plaster finish
12.90 0.05 0.645
Glass wall (Double Glazing 2-3mm glass with 10mm glass gap)
102.67 0.02 2.053
Floor Timber 74.90 0.06 4.500 Ceiling Plywood
(Plywood 5mm, on battens 50mm airspace filled with glass wool)
74.90 0.05 3.745
People - 20 0.45 9.00 Furniture Leather covered 20.00 0.58 11.60 Total Absorption, A 31.543 Reverberation Time, RT = (0.16xV)/A = (0.16x 224.70)/31.543 =1.14s Wood Flooring with carpet Material Absorption Coefficient at 500 Hz Building Component
Material Area (m^2) Absorption Coefficient, a
Sound Absorption, Sa
Wall Brick wall with plaster finish
12.90 0.02 0.258
Glass wall (Double Glazing 2-3mm glass with 10mm glass gap)
102.67 0.03 3.080
Floor Timber with carpet 74.90 0.25 18.725 Ceiling Plywood
(Plywood 5mm, on battens 50mm airspace filled with glass wool)
74.90 0.20 14.980
People - 20 0.45 9.00 Furniture Leather covered 20.00 0.58 11.60 Total Absorption, A 57.64 Reverberation Time, RT = (0.16xV)/A = (0.16x 224.70)/57.64 =0.62s Wood Flooring with carpet Material Absorption Coefficient at 2000 Hz Building Component
Material Area (m^2) Absorption Coefficient, a
Sound Absorption, Sa
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Wall Brick wall with plaster finish
12.90 0.05 0.645
Glass wall (Double Glazing 2-3mm glass with 10mm glass gap)
102.67 0.02 2.053
Floor Timber 74.90 0.25 18.725 Ceiling Plywood
(Plywood 5mm, on battens 50mm airspace filled with glass wool)
74.90 0.05 3.745
People - 20 0.45 9.00 Furniture Leather covered 20.00 0.58 11.60 Total Absorption, A 45.768 Reverberation Time, RT = (0.16xV)/A = (0.16x 224.70)/45.768 =0.79s
The result shows that reverberation time for the study room is 0.77s and 1.14s under
500Hz and 2000 Hz room. It is slightly higher than the required RT, which is 0.6-0.7s. RT can
be lower down by increasing the absorption material into the room. This can be done by adding
carpet to the floor and adding soft furniture. In order to absorb both low and high frequency, it is
necessarily to suspend the ceiling below the structural ceiling. Adding carpet does not
significantly reduce the reverberation time especially when at low frequencies, but carpeting
can reduce the noise resulting from users sliding their chairs or desks.
2.2 Sound Transmission Loss (STL)
Insulation is the principal method of controlling both airborne sound and impact sound
in buildings. The measure of sound insulation against the airborne sound is known as the
Sound Reduction Index. It is measured in the laboratories with varied materials. Sound
reduction index needs to be measured for different frequency bands to achieve maximum
insulation.
The range of acceptable sound range is measured by using noise criteria curve, which
provided different range of frequency and desirable decibels depends on the function and
material used in the room.
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Table 3 Noise Criteria and dB at 500HZ
NC25 31dB NC30 35dB NC35 40dB NC40 44dB NC45 49dB NC50 54dB
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Space 1: Entrance Noise Criteria: 35-40 Required dB: 40-44dB
Building Element
Material Surface Area (m^2)
SRI (dB) Transmission Coefficient, T
ST
Wall Double Glazing Glass 3mmwith 10mm airspace
(13.607×3) −9.6=31.221
32 6.31×10−4 0.0197
Door Glass (0.8×3) ×4=9.6 23 5.012×10!! 0.0481 Total ST = 0.0678
𝑇 = !
!"#$%&' !"#!"
𝑇𝑎𝑣 = S1T1 + S2T2 + SnTn
Total Surface Area
= 0.0678
40.821
= 1.658×10!! hence, the Average Transmission of the wall is 1.658×10!!
Figure 24 Glass wall between the public realm and Administration Area
80 dB
74 dB
-6dB
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SRI= 10 𝐿𝑜𝑔10 !!"#
= 10 𝐿𝑜𝑔10 1
1.658×10−3
= 27.8dB Hence, the Overall SRI of the wall is 38.2 dB 74dB – 27.8dB = 46.2dB
The landscape area reduces the 80 dB noise levels from the street by 6dB; therefore
the total of 74dB is entering the building. The glass wall then reduces the noise by 27.8dB.
Total noise level at the entrance is 46.2dB. According to the NC curve, at 500Hz, the required
NC at the entrance is 35-40, which is equivalent to 40-44 db. The resultant value is more than
the standard by 2.2dB. This is due to the low SRI value of the glass. There’s available
insulating glass for example triple insulating glass, which can achieve until 41 STC value. The
existence of sliding door can also increase the noise level at the entrance. Therefore, a
suggestion of double entrance is preferred. Have double entrance can prevent the noise from
the street from directly enter the building.
Space 2: Reading Area Noise Criteria: 25-30 Required dB: 31-35dB
Figure 25 Glass wall between the Reading Area and Corridor
45 dB
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𝑇 = !
!"#$%&' !"#!"
𝑇𝑎𝑣 = S1T1 + S2T2 + SnTn
Total Surface Area
= 0.0653
36.86
= 1.763×10!! hence, the Average Transmission of the wall is 1.763×10!! SRI= 10 𝐿𝑜𝑔10 !
!"#
= 10 𝐿𝑜𝑔10 1
1.763×10−3
= 27.54dB Hence, the Overall SRI of the wall is 27.54 dB
45dB – 27.54dB = 17.46dB
The corridor noise level is 45dB as no seating area are provided. Therefore, the glass
wall is appropriate for absorbing 27.58dB noise. However, is facing the street this would
creates issues. Adding insulating panels to the walls to increase the STC value or increase the
air space and thickness of the glass to achieve desirable STC and thus absorb more noise.
Building Element
Material Surface Area (m^2)
SRI (dB) Transmission Coefficient, T
ST
Wall Double Glazing Glass 3mmwith 10mm airspace
(12.287×3)-9.6 =27.261
32 6.31×10−4 0.0172
Door Glass (0.8×3) ×4=9.6 23 5.012×10!! 0.0481 Total ST = 0.0653