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7/23/2019 Transmission Coefficient u Final
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Najran Court Complex
Calculation of
Transmission Coefficient ( U )
.
7/23/2019 Transmission Coefficient u Final
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Transmission Coefficient U
Btu/hr. Ft2. F
Heat Gain (Btu/hr) = Area x U x t (out!oor tem". # in!oor tem".)
$etermine the %esistance (%) of the structure
R = R1+ R2+ R3+ .. Rn
Then:&
U=
%
1- Masonry Parttons
2- Masonry !xposures
3- "lat Roo# $th Roo# % &e'( )nsulaton
*- Transmsson Coe##'ent #or $no,s.
.
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&' asonr *artitions
2mm ollo, /lo'( 0r2
2mm an Plaster 0 r1 ( 2mm an Plaster 0r3
Masonry Parttons stru'ture
Masonry Parttons stru'ture Materal:
2mm ollo, /lo'( ,th /oth ses san plaster 2mm as sho,n n ta4le 25
0Transmsson 'oe##'ent % masonry partton Part 1 loa estmatn6 Carrer an4oo(.
U = +.,&
.
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2 ' asonr -x"osures
2 mm 'on'rete 4lo'( 0R3 7 mm nsulaton 0R*
2 mm an Plaster 0R2 17 mm 'on'rete 4lo'( 0R7
)nse sur#a'e resstan'e 0R1
8utse sur#a'e resstan'e 0R9
8utse Masonry $alls tru'ture
st o# outse ,all materal:
1. )nse ur#a'e Resstan'e R1= .59
2. 2 mm an Plaster R2 = .17
3. 2 mm ea;y Con'rete /lo'( R3= 1.*
*. 7 mm !xtrue polystyrene R*= 9.9* a#ter 7 years o# nstallaton
7. 17 mm ea;y Con'rete /lo'( R7= .hr. #t2. ?"
R 11.
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ote0 1all construction as "er architectural !etails.
All %'alues are 3ase! on A4H%A- Fun!amentals Ch. 25 an! local manufacturers6 s"ecifications.
3 - Roo# ,th Roo# % &e'( )nsulaton
.
2 mm tles
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Roo# stru'ture Materal
Con'rete th'(ness s 2* mm ,th 5 mm nsulaton on top o# e'( as sho,n a4o;e
Roo# &e'( Materal R ;alues:
1. 8utse sur#a'e resstan'e R1= .27
2. Tles san 'ement an mortar R2= .37
3. 7 mm !xtrue polystyrene R3= @.* a#ter 7 years o# nstallaton
*. * mm ,ater proo# mem4rane R*= .127. 7 mm slope s'ree R7= 1.7*
5. 25 mm hea;y,e6ht 'on'rete R5= .
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U = +.+75 Btu/hr. Ft2. F
ote0 %oof construction as "er structural an! architectural !etails
All %'alues are 3ase! on A4H%A- Fun!amentals Ch. 25 an! local manufacturers6 s"ecifications.
8 ' Transmission Coefficient for 1in!o9s
&ou4le 6lass ,no, 5mm 6reen + 12mm ar 6a4 + 5mm 'lear 0Al. #rame ,thout
thermal 4rea(
A''orn6 to ARA! "unamentals 'hapter "-31 0Ta4le *:
.
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U = +.:7 Btu/hr. Ft2. F
A''orn6 to ARA! "unamentals 'hapter "-31 0Ta4le 13 solar heat 6an 'oe##'ent
BC = .29 #or e = .7 on sur#a'e 2
han6 Coe##'ent:
C = BC>.9< = .32
.
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