Document 6bjY8oMNVYdmnx5m8L8NoM6M1
192
CHAPTER 9
1955 Guide)
Table 16. Coefficients of Transmission (U) of Flat Roofs Covered with3
Built-up Roofing. With Lath and Plaster Ceilings"*
' '|
(See Table 15 for Flat Roofs with No Ceilings)
,
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These coefficients are exproceed in Bin per (hour) (square foot) (Fahrenheit degreedifference in temperature
between the air cm the two sides), and are baaed an an outside wind velocity o] 16 mph.
----------------------------- -
''
,'sL*
Insulation on Top of Deck (CoVEBBD WITH BuILT-Up ROOFING).
Ttpe of Roof Deck
Thick- No In| NESS of I sula-
Roof TION , Decs (Inches)
Inbulatinq Boabd (Thickness Below)
tin.
It In-
COBKBOABD
(Thickness Below)
It In. 2 In.
NUHBEfi
M
H
Flat Metal Roof Deck injoutwrt/ nt
0.46 0.27
0.12 0.18 0.14 0.11
Precast Cement Tile ftflIFftftfr /fttt T!/yrroi.T/-A
It in.
0.15 0.12 0.18 0.14 0.11
-t#
. nvouYum.
,0.42
0.40 0.37
0.26 0.25
0.24
0.19
0.18 0.18
0.14 0.12 0.14. 0.12
0.14 0.11
0.18 0.17
0.17
0.14
0.13 0.13
0.11 0.11 0.11
Gypsum Fiber Concrete* on } in. Gypsum Board
0.27 . 0.19 0.23 0.17
0.15 0.14
0.12 0.11
0.10 0.14 0.097 0.13
0.12 0.11
0.097 0.091
Wood*
UW(1laTiOT1>
ROOFlftgj
/
3BBEBJSB
0.31 0.26
0.24 0.18
0.21 0.19
0.17 0.14
0.16 0.15 0.14
0.12
0.13
0.12 0.11 0.10
0.11 0.10 0.097
0.087
0-15 0.14
0.13
0.11
0.12
0.11 0.11 0.095
0.10 0.095 0.092
0.082
* SCeaelcTualabtlieon5s, Nbaosteeda.on metal lath and plaster ceilings, but coefficients may be used with sufficient*^' curacy for gypsum lath or wood lath and plaster ceilings. It is assumed that there is an air space between-.
the under side of * 87H percent
the roof deck and the gypsum, 12>4 percent
upper side of the ceiling. wood fiber. Thickness indicated
includes
Yi
in.
gypsum
board-
.
* Nominal thicknesses specified--actual thicknesses used in calculations.
f'*