Building Science daylight and artificial light analysis

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1.0 Introduction
Site
The CommunityLibraryislocatedwithinan
urban infill site,JalanTuankuAbdul Rahman.
It isflankedbypre-warbuildingsand
readaptedfacadesformodernretailing
businessalongthe street. Toretainthe
characteristicof Jalan TAR streetfaçade,the
oldfacade of the site isretainedwhileanew
blockisaddedbehindthuscreatinga remix
of facades.
Intention
The libraryservestoprovide studyareafor
the readersas several bookstoresare
available atthe site where theysell revision
workbookforstudentsaswell asreligion
bookas there isnot a spot forstudyarea in
JalanTuankuAbdul Rahmanitself.The
libraryaimsto gatherthe communityand
provide space forinteractionstohappen.
The courtyard servesasa performance
space whichcouldserve as a meetingpoint
that enhance communityrelationship.The
formof the newblockrespectthe old
buildingbyfollowingthe wedge of the
existing.Italsoconsistsof pitch roof which
will tone downthe 4-storeylibrary.
SunPath
At 9am, bookstore whichislocatedatthe frontwill receive adequate sunlightasthe whole
space is setback 5m from the five footwaythusposesnothreat suchas toobrightor glare
issue.
At 2pm, the incidentsunlightiscomingmainlyfromthe topwestdirection,affectingthe
readingareamainlyviathe voidof the courtyard.Louvre screenwiththe helpof bambooplant
will diffuse directlightbeforereachingintothe space.
9am 2pm 6pm

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2.0 LightingAnalysis
2.1 DaylightFactorAnalysis
Daylightfactoris definedasthe ratioof interiorilluminance,Ei toavailableoutdoorilluminance,Eo
whichisthe unobstructedhorizontal externalilluminance:
Zone DF (%) Distribution
Very bright >6 Large (including thermal and
glare problem)
Bright 3-6 Good
Average 1-3 Fair
Dark 0-1 Poor
Luminance Level (lux) Example
120,000 Brightest Sunlight
110,000 Bright Sunlight
20,000 Shade illuminatedbyentire clear blue sky, midday
1000-2000 Typical overcast day, midday
400 Sunrise / sunsetonclear day(ambientillumination)
<200 Extreme of darkest storm clouds, midday
40 Fully overcast, sunrise/sunset
<1 Extreme of darkest storm cloud, sunrise/sunset
Base on the table,the average outdoorilluminance inMalaysiaisassume tobe 20000 lux.
DF = Ei (indoorIlluminance) x 100%
E0 (outdoor illuminance)
MS1525 Daylight Factor Distribution

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Non-fictionReadingarea
The selected reading area is located in the middle of the building. The front block (preserved
shophouse) thus block more sunlight, reducing the visible sky angle from the centre of the
window to 40º.
FirstFloorPlan
ReadingArea

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DaylightCalculation
Average DF = W/A X T θ /(1-R)
= 18.816 /233.28 X [(0.6 X 40)/ (1-0.4)]
= 3.2%
WindowArea(m2
) 8.4 X 3.2 = 26.88m2
W 26.88 X 0.7 =18.816 m2
T 0.6 (fordouble-glazedwindowsinclean
environment)
θ 40º
A 2(8.4 X 7.2) + 2(8.4 X 3.6) + 2 (7.2 X 3.6)
= 233.28 m2

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FloorArea(m2
) 60.48
Areaof façade exposedto
light(m2
)
Perimeter=8.4
Height= 3.6
Area= 30.24
Exposedfaçade tolight&
skylightareatofloorarea
ratio(daylightfactor)
30.24/60.48
= 0.5 (50%)
= 50 x 0.1
= 5
Daylightfactor,DF DF=Ei/Eox 100%
5= Ei/2000 x 100%
Ei = 1000 lux
40º
Diagram
Obstruction
DiscussionRoom
40º
Sectional Perspective
PreservedBlock

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DaylightContour
Conclusion
The selectedreadingareahasa daylightfactorof 3.2% andnatural illuminationof 1000 lux.Based
on the recommendationof MS1525, readingarea shouldhasilluminance between300 lux to500
lux,thusthisreadingmightcause discomfortandglare tousersat the readingarea.Thisissue canbe
resolvedbyaddingblindstoreduce the sunlightcomingfromthe courtyarddirectionduringthe day.
Thisissue can alsobe tackledanotherwayif realise duringthe designphase.Incorporatingfully
operable woodenlouvre tothe façade systemisagood optionasadequate amountof sunlightis
allowedtopenetrate intothe space dependingonthe weatherof the day,maximizingnatural
lightingwhenrequired.

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3. Artificial LightingAnalysis
3.1 Non-fictionReadingarea
LumenMethod
In lightingdesign,the lumenmethod,(alsocalledzonal cavity method),isasimplified method to
calculate the lightlevel inaroom.The methodisa seriesof calculationsthatuseshorizontal
illuminance criteriatoestablishauniformluminaire layoutinaspace.
FirstFloorPlan
ReadingArea

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LightingFixture Properties

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LumenMethodCalculation
Dimensionof room(m2
) L = 7.2, W = 8.4
Total floorarea(m2)
60.48
Heightof Ceiling 3.6
Type of lightfixture FluorescentLamp
Luminousflux of lighting,F(lm) 1750
Heightof luminaries (m) 3.4
Heightof workingplane 1.5
Mountingheight(Hm) 3.6 - 0.2 - 1.5 = 1.9
Reflectance factor Ceiling(Whiteplasteredceiling) =0.7
Wall (White wall )=0.5
WorkingPlane (woodendecking)=0.1
Roomindex,RI(K) RI = L X W
Hm X (L + W)
RI = 60.48/[ 1.9 x (7.2+8.4)]
= 2.04
UtilizationFactor,UF 0.59
Maintenance factor,MF 0.8 (standard)
Numberof fittingsrequired,N N = E x A
F X UF X MF
N = (300 X 60.48)/ (1750 X 0.59 X 0.8)
=22 bulbs
Spacingto heightratio,SHR SHR= 1/Hm X √A/N
=1/1.9 x √60.48/22
= 0.8
SHR = S/Hm
0.80 = S/1.9
S = 1.52
FittingLayout Fittingrequiredalong7.2mwall
7.2/1.52 (m) = 4.73 ~ 5 rows
Numberof lampsineach row along8.4m wall
22/5 = 4.4 ~5 rows
Therefore,5X 5 = 25 bulbs(more than22
bulbs)
To achieve the recommendedMS1525 reading
area of 300 lux
x-spacingrequiredfor7.2m wall is7.2/5 = 1.44
y-spacingrequiredfor8.4mwall is8.4/5 =
1.68m
FirstSpacingfor the 7.2m wall will be half of the S,1.44/2 = 0.72m
FirstSpacingfor the 8.4m wall will be half of the S,1.68/2 = 0.84m

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LightFittingsSpacingDiagram
Artificial lightingcontour
LightingContourwhenall artificial lightison

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PSALI (PermanentSupplementaryArtificiallightingof Interior)
As the readingareaislocatedmore than 4.5m awayfromthe courtyard,every1m intothe reading
area reducesindaylightsignificantly.The lightfittingisplanina wayof row 1,3,5 will onlybe
neededtoswitchonwhenitisdark to illuminatethe cornersof the roomwhile switchingon row 2
and 4 alreadyprovide sufficientlightingtothe userinthe space duringthe day.
SW1
SW2
LightingContourwhenswitch1is switchon(Row 1,3,5)
SW2
SW1
LightingContourwhenswitch2is switchon(Row 2,4)

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3.2 Bookstore
Ground FloorPlan

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Contourdiagramof groundfloordaylightfactor

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LightingFixture Properties

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Dimensionof room(m2
) L= 8.87, W = 5.95
Total floorarea(m2)
52.78
Heightof Ceiling 3.0
Type of lightfixture LED Lighting
Luminousflux of lighting,F(lm) 1521
Heightof luminaries(m) 3.0
Heightof workingplane 1.0
Mountingheight(Hm) 3.0-1.0 = 2.0
Reflectance factor Ceiling(Whiteplasteredceiling) =0.7
Wall (White wall )=0.5
WorkingPlane (woodendecking)=0.1
Roomindex,RI(K) RI = L X W
Hm X (L + W)
RI = 52.78/ [ 2.0 x (8.87+5.95)]
= 1.78
UtilizationFactor, UF 0.59
Maintenance factor,MF 0.8 (standard)
Numberof fittingsrequired,N N = E x A
F X UF X MF
N = (300 X 52.78)/ (1521 X 0.59 X 0.8)
=22 bulbs
Spacingto heightratio,SHR SHR= 1/Hm X √A/N
=1/2.0 x √52.78/22
= 0.77
SHR = S/Hm
0.77 = S/2.0
S = 1.54
FittingLayout Fittingrequiredalong5.95mwall
5.95/1.54 (m) = 3.86 ~ 4 rows
Numberof lampsineach row
22/4 = 5.5 ~6 lamps
Therefore,6X 4 = 24 bulbs(more than22
bulbs)
To achieve the recommendedMS1525 reading
area of 300 lux
x-spacingrequiredfor5.95m wall is5.95/4 =
1.49mm
y-spacingrequiredfor8.4mwall is 8.87/6 =
1.48m

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FirstSpacingfor the 5.95 wall will be half of the S, 1.49/2 = 0.75m
FirstSpacingfor the 8.4m wall will be half of the S,1.48/2 = 0.74m
LightFittingsSpacingDiagram
Artificial lighting+daylightcontour

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PSALI(PermanentSupplementaryArtificiallightingof Interior)
Basedon the lightingcontourof artificial lightinganddaylightcontour(page 17),it isnotice that
lightfromrow 1 and 6 can be switchoff duringthe day as there isenoughdaylightemittingintothe
space. Bookstore requireslesseramountof lightcomparedtothe library.However,row 1 and6
mustbe onduringthe darkwhenthere isnot daylightpenetratingintothe space.