TM 5-852-4/AFM 88-19, Chap. 4
DISTANCE FROM WALL IN FEET
U. S. Army Corps of Engineers
Figure 4-35. Comparison of predicted and measured floor temperatures for a concrete slab on gravel with vertical
insulation (same case as fig 4-33 41). Insulation 1 1/2-inches x 36 inches cellular glass except 3/4-inches x 18-inches
rubber board for Test Floor 7. Room temperature 77F. Outside temperature 32F except 35F in Loring AFB
measurements. Data for test floor 7204 adjusted from lower room temperature of 70ƒF by adding 7F to all temperatures
(from Government sources).
result partly of simplifications in the assumed boundary
were developed from theoretical studies of heat flow by
conditions for the flow net and electrical analog analyses,
an electrical analog method, verified in part by field data.
partly of such factors as localized cooling by the
Both figures show curves for no condensation over 6 in.
downward movement to the floor of cold air on the inside
from the edge of the wall. Recommended practice for
face of the exterior wall of the field test facility, and partly
insulation of concrete slab-on-grade structures is
of the fact that the analytical approaches assume steady
presented in table 4-3.
state conditions but these are probably never achieved in
(j) Basements are desirable in areas
the field situation.
of deep seasonal frost because heat losses tend to
(i) If it is assumed that the air
prevent or reduce frost grip on perimeter walls and
temperature in a mess hall or kitchen is 70 F and the
foundations; however, a basement or underground
relative humidity is 70 percent, the floor surface
facility in permafrost may be a source of structurally
temperature can not be lower than 60F if the floor is to
dangerous heat loss. Heat losses and wall and floor
remain condensation free. For quarters or similar areas,
surface temperatures in partial or full basement or
a relative humidity of 40 percent and air temperature of
below-grade heated spaces may be calculated by
117
procedures outlined in the ASHRAE Guide ,
70F will allow floor surface temperature to drop to 45
extrapolated as necessary to arctic and subarctic
OF without condensation. Using these criteria, the
temperature ranges, and insulation
curves of required insulation thermal resistance versus
design winter 4-50 temperature in figures 4-36 and 4-37
4-50
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