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American Society of Heating and Ventilating Engineers Guide, 1928
Chapter . I--Calculating the Heat Losses from Buildings
Table 11-B. Coefficients of Transmis$$ U) OF Various Types of Pitched Roofs
Note.--The figures on this page difference in temperature between
are the the air
cuonmdebrinneedatcho'tehfeficcieeniltisngofatrnadnsthmeisosuiotns;iidcdeer
. ;a;r
.
. , -* v
.x a
and are exoressed in B.t.u. per hour per square foot of roof area per 1 deg. fahr.
AnTMverag^|"i;"ureof l,5 mfe has been assumed. These coefficients are based on M pitched roofs, but are sufficiently
accurate for roofs ranging from pitch to ^ pitch.
"5
Ukjueatcd
Attics
The Values of \J in this Table are based on the /bllowinq Internal '
Conductivities (C) which are expressed in BLu. per Hr. per 5q. FL per lF
Asphalt or Composition Loo/inq
6.50 per I'
Asbestos Shmqles Slate Shmqles Wood -(Yellow Pine or Fir) Wood Lath 4 Plaster Plaster Board Plaster- (Gypsum) Fiber Insulation (board form) Felt or Quilt Insulation (sc/t) Cort board
6.00
10.57 1.00
Z.OO 3.04 Z.31 .. 0.33 0.Z7 0.30
per f
per F per 1"
as applied per F per 1' per 1` per l" per I'
Cellular Gypsum Powdered. Gypsum
0.5Z per 1" 0.5q per 1"
Typical Construction
Hoo/mcj --v VLoof SheaVluncj
..... . " .......
cgjS
Unbeaten! Attic
"^-Attic.floorinq
PI aster 0>ase Plaster Oeilmq
Type of
Insulation on
Insulation
Type of Qoo/inq and G.oof Sheathmq
Ceiluiq.
IL O -O
underside of ioof Pa/ters
between Ceilmq Joists
Wood *5htnqles
Asphalt Shmqles or
on Wood Strips * Composition Eoo/inq
on Wood Sheathmq
Eiiqid Asbestos <5hinqles' on Wood Sheaihinq
Slate or Tile and Coo/mq Felt on Wood Sheathmq
Ho M y. p T Ho l\b` X. R * Ho
1x6* Y. P. Ho
Fx6` Y.P. *
t c0u
Attic Attic Floorinq Floorinq
ab
Attic Floorinq
c
Attic Floorinq
d
Attic Floorinq
e
Attic Floorinq
f
Attic Floorinq
q
Attic Floorinq
h
251 Wood. Lath f Plaster ('/)
Done
Hone
0-224 0.138 0.231 0.141
0.230 0.141
O.Z37 0.143
i Z52 Wood Lath 4 Plaster ('/z)
Hone
1' Felt or Quilt * Insulation (So/t)
0.11.8 0.088 0.120 0.080 . 0.120 0.080 0.121 0.081
Z53 Wood Lath' 4 Plaster ('/z`) '254 Wood Lath 4 Plaster ('/z")
sfi Fiber Insulation (Board form)
Hone
Yl Fiber Insulation t (Board form)
Cellular Gypsum fill
0.080 0.085
0.074 0.078
0.081 . 0.073 0.081 0.086 0.078. 0.086
0.073 0.078
0.088 0.074 0.086 0.080
I 255 Wood Lath 4 Plaster ('/z`)
Hone
Powdered Gypsum fill'.
0.078 0.073 0.078 0.074 0.078 . 0.074 0.080 0.074
256 ^Plaster Board 4 Plaster (Vi")
Hone
Hone
0.235 0.143 0.243 0.146 0.Z42 0.146 01248 0.148'
257 Wz CorLboard 4 Plaster ('/z")
Hone
klone ;
'
0.088 0.078 0.100 0.078 0.100 0.078 0.101 0.078
258 2* Cort board 4 Plaster ('/z')
Hone
Hone
It" Fiber Insulation 258 (Board/orm) \ Plaster ('/z")
Hone
Hone
260 '
W Fiber Insulation (Board form) 4 Plaster Q/f)
Yl fiber Insulation Vz fiber Insulation
(>oard form)
(board form)
Based on 1 in. by 4 in., spaced 2 in. fCan also be applied to underside of ceiling joists with furring strips between insulation and ceiling,
iBased on actual thickness of 1 in. lumber of approximately H in-
42
0.082 0.067 0.083 0.068 0.083 0.068 0.084 0.068
0.168 0.115 0.172 0.117 0.172 0.117
0.176 0.118
0.080 0.066 0.080 0.066 0.080 0.066 0.081 0.067.
Based on 1 in. by 4 in., spaced 2 in. fCan also be applied to underside of ceiling joists with furring strips between insulation and ceiling, .tBased on actual thickness of 1 in. lumber of approximately H in.
43