Civil Engineering Reference
In-Depth Information
Table 14-4. Insulation Values of Various Materials
Thermal resistance,
R
, for
10-mm (1-in.) thickness
of material,* (m
2
· K)/W
Material
Density kg/m
3
(lb/ft
3
)
([°F · hr · ft
2
]/Btu)
Board and Slabs
Expanded polyurethane
24 (1.5)
0.438 (6.25)
Expanded polystyrene, extruded smooth-skin surface
29 to 56 (1.8 to 3.5)
0.347 (5.0)
Expanded polystyrene, extruded cut-cell surface
29 (1.8)
0.277 (4.0)
Glass fiber, organic bonded
64 to 144 (4 to 9)
0.277 (4.0)
Expanded polystyrene, molded beads
16 (1)
0.247 (3.85)
Mineral fiber with resin binder
240 (15)
0.239 (3.45)
Mineral fiberboard, wet felted
256 to 272 (16 to 17)
0.204 (2.94)
Vegetable fiberboard sheathing
288 (18)
0.182 (2.64)
Cellular glass
136 (8.5)
0.201 (2.86)
Laminated paperboard
480 (30)
0.139 (2.00)
Particle board (low density)
590 (37)
0.128 (1.85)
Plywood
545 (34)
0.087 (1.24)
Loose fill
Wood fiber, soft woods
32 to 56 (2.0 to 3.5)
0.231 (3.33)
Perlite (expanded)
80 to 128 (5.0 to 8.0)
0.187 (2.70)
Vermiculite (exfoliated)
64 to 96 (4.0 to 6.0)
0.157 (2.27)
Vermiculite (exfoliated)
112 to 131 (7.0 to 8.2)
0.148 (2.13)
Sawdust or shavings
128 to 240 (8.0 to 15.0)
0.154 (2.22)
Thermal resistance,
R
, for
Material thickness
thickness of material,*
Material
mm (in.)
(m
2
· K)/W ([°F · hr · ft
2
]/Btu)
Mineral fiber blanket, fibrous form (rock, slag, or glass)
50 to 70 (2 to 2.75)
1.23 (7)
5 to 32 kg/m
3
(0.3 to 2 lb/ft
3
)
75 to 85 (3 to 3.5)
1.90 (11)
90 to 165 (5.5 to 6.5)
3.34 (19)
Mineral fiber loose fill (rock, slag, or glass)
95 to 125 (3.75 to 5)
1.90 (11)
10 to 32 kg/m
3
(0.6 to 2 lb/ft
3
)
165 to 220 (6.5 to 8.75)
3.34 (19)
190 to 250 (7.5 to 10)
3.87 (22)
260 to 350 (10.25 to 13.75)
5.28 (30)
* Values are from
ASHRAE Handbook of Fundamentals,
American Society of Heating, Refrigerating, and Air-conditioning Engineers, Inc., New
York, 1977 and 1981.
R
values are the reciprocal of U values (conductivity).
should be checked and appropriate action taken for
expected temperature changes.
Columns and walls should not be cast on foundations
at temperatures below 0°C (32°F) because chilling of con-
crete in the bottom of the column or wall will retard
strength development. Concrete should not be placed on
any surface that would lower the temperature of the as-
placed concrete below the minimum values shown on Line
4 in Table 14-1.
ENCLOSURES
Heated enclosures are very effective for protecting
concrete in cold weather, but are probably the most expen-
sive too (Fig. 14-17). Enclosures can be of wood, canvas
tarpaulins, or polyethylene film (Fig. 14-18). Prefabricated,
rigid-plastic enclosures are also available. Plastic enclo-
Fig. 14-17. Even in the winter, an outdoor swimming pool
can be constructed if a heated enclosure is used. (43453)
