Document JXDvrG8VOmzeyjEVb6b38DxK
American Society of Heating and Ventilating Engineers Guide, 1931 66
I Chapter 3--Heat Losses by Transmission
TiRiR 31 Coefficients of Transmission (U) of Pitched Roofs 1 Over Heated Attics
_ TflKSE coefficients are expressed in B.t.u. per hour per square foot PER 1 DEC. FAHR.
SSSVl.NoU. ^ .JVtnLTPKttATURE BETWEEN THE AIR ON THE TWO SIDES AND ARB BASED ON AN OUTSIDE WIND MILES FEE HOVE.
The values of Umtbis Table are basedonthefollawinq Internal Conductivities or Conductances which are "
expressed in Eb.t.u. per Ur per Sq..F.t.. ppeerr l.*F.
AspbaltcrComposition Boofmq '6.r5A0 -a--s-a--p--p1lie- d
Asbestos Shinqtes
Slate Shmqles Wood (Yellow Roe or Fir) Wood Lath 1 Plaster Raster board Plaster (Gypsum) Eiqid lnsulation(&oardform) Flexible Insulation, Cork board Cellular Gypsum (I6*>
6.00 asapplied 10.57 pert'
1.00 perl L.00 asapplied
3.75 peri" 2.32 per?"
0.33 per I" O.T7 per r 0.30 per I" 0.53 perF
" A-------- i**' \ rw,,
0.46 per I"
Typical Construction Boofmq-
Rodf Sheathinq.
Plaster Plaster base
TvPe of Cetlmq
4w>
Typt of Boofmq Insulation No Metal Plaster Wood.
TBiqid ifCork rCork-
and Goof
between Cetlutq Lath ,, board \Mm tnsaJa- Insula- board board
Slieathmq
Hoof Batters
and? and? andx
-hanti' and x and?
Plaster Plaster Plaster Plaster Plaster Plaster Plaster
A e> C D e F G W
i
None
0483 0.303 0.281 0288 0.212 0.161 0.122 0.102
i
3
Wood Shmqles i" Flexible b onWood5tnpS f Flexible b
0.165 0.161 0.160 0.134 am 0.011 0.071 0.116 a 124 0.124 0.107 0.012 0.078 0061
4
If"CGeylplusluamr c
0.112 0110 0.110 0.017 0085 0.072 0.065
5
SI"GFylapkseudm n
0.037 0016 0.016 0.085 0.076 0.066 0.051
(o
Nona
0.518 0.316' 0.301 0.300 0.211 0.164 0.124 0103
7 Asphalt Shmqles ? Flexible
8
or Composition Boofmq on Wood
1* Flexible
b
1 Sbeatbmq
31' Cellular c Gvpsum
10 Ji"GPylapsteudm l
0.161 0.165 0.164 0136 0.113 0.012 0.080 0.121 0.126 0.126 0.101 0.014 0.071 0.070 0.120 0.117 0.117 0102 0.088 0.076 0.067 0.102 0.101 0.101 0.081 0.071 0.068 0061
II
None
0.515 0.315 0.300 0.218 0.218 0.164 0.124 0.103
12 ftiqid Asbestos Flexible b
13
Shmqles on Wood SVieatVunq
1* Flexible b
14 3|" CGeypllusulamr c
15 si"GHyaptseudm o
0.161 0.164 0.164' 0136 0.113 0.012 0.080 0.121 0.126 0116 aioi 0.013 0071 0.070 0.111 0.117 o.in 0.102 0088 0.075 0.067 0.102 0.101 0.100 0081 0071 0.068 6-Obl
16
None
0.548 0.327 0.3U 0.301 0.224 0.167 0.126 0.104
17 Slate or Tile
16
and B.oofinq Felt on Wood
17 SWeatVimq
18
?'Flexible b
T Flexible b 3I'CGyepilsuulamr c 31"GFylapkseudm.. C
0.172 0.167 0.167 0.138 OllA 0.013 0.081
0.131 0.128 0.121 0.110 0.015 0.080 0.070 OI2I 0.118 0.118 0.103 0.081 0.076 0.067 0.103 O10I o!ioi 0.010 0.071 0.061 0062
.Based on 1 in. by 4 in. strips spaced 2 in. bCan also be applied to underside of roof rafters with furring strips between. cAssumed in. thick, based on 2 in. by 4 in. raftere.
The coefficient used for cellular gypsum, 0.59 is for 18 lb. weight--weights as low as 12 lb. may be usee