Section CA106 On-Grade Slab Floors
Table CA106.1 lists heat loss coefficients for heated on-grade slab floors, in units of
Btu/h × °F per lineal foot of perimeter.
DEFAULT F-FACTORS FOR ON-GRADE SLABS
|2 ft Horizontal (No thermal break)||—||0.70||0.70||0.69|
|4 ft Horizontal (No thermal break)||—||0.67||0.64||0.63|
|2 ft Vertical||—||0.58||0.54||0.52|
|4 ft Vertical||—||0.54||0.48||0.45|
|Fully insulated slab||—||—||0.36||—|
|Fully insulated slab||—||0.74||0.55||0.44|
|R-5 Center (With perimeter insulation)||—||—||0.66||0.62|
|R-10 Center (With perimeter insulation)||—||—||—||0.51|
|3 ft Vertical||—||—||0.78||—|
For SI: 1 foot = 304.8 mm.
All on-grade slab floors are assumed to be 6-inch (610 mm) concrete poured directly onto the earth. The bottom of the slab is assumed to be at grade line. Monolithic and floating slabs are not differentiated.
Soil is assumed to have a conductivity of 0.75 Btu/h × ft2 × °F. Slabs 2 feet (610 mm) or more below grade should use basement coefficients.
Coefficients are provided for the following three configurations: