Bb science project 2

1

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

2

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

3

Daylight Factor

Using the daylight factor formula, illuminance of the book collection area can be calculated.


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

4

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

5


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

6

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

7

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

8

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

9

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

10

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

11

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



=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)



5.0𝑋 15.545.0+ 15.54 𝑋1.75

𝑁 = !"" ! !!.!(!"## ! !.!"! !.!)

12

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 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

13

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 Temperature, K - Colour Designation White

Figure 14 Reading Areas at Second Floor

14

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



=1/1.75x 64/19 =1.05

SHR=!

!.!" = 1.05

S= 1.75 x 1.05 =1.8


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



3.7 𝑋 12.443.7+ 12.44 1.75



15

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

16

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 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

17

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



=1/0.75x 47.22/12 =2.64m

SHR=!

!.!" = 2.64

S= 0.75 x 2.64 =1.98 ⋍2m


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



5.1 𝑋 9.265.1+ 9.26 0.75



18

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

19

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

20

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




10.74 0.05 0.538


56.76 0.02 1.135

Floor Carpet 29.00 0.30 8.700 Ceiling Plywood


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.

21

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




12.90 0.02 0.258


102.67 0.03 3.080

Floor Timber 74.90 0.10 7.490 Ceiling Plywood


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

22

Wood Flooring without carpeted Material Absorption Coefficient at 2000 Hz Building Component




12.90 0.05 0.645


102.67 0.02 2.053



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




12.90 0.02 0.258


102.67 0.03 3.080

Floor Timber with carpet 74.90 0.25 18.725 Ceiling Plywood


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



23


12.90 0.05 0.645


102.67 0.02 2.053



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.

24

Table 3 Noise Criteria and dB at 500HZ

NC25 31dB NC30 35dB NC35 40dB NC40 44dB NC45 49dB NC50 54dB

25

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

26

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

27

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

Bb science project 2

Science

Transcript of Bb science project 2