Page 34
Installation and Operation Manual - Inspire 2000 Insert
MATERIAL
CONDUCTIVITY (K)
PER INCH
RESISTANCE (R) PER INCH
THICKNESS
Concrete
1.050
0.950
Mineral wool insulation
0.320
3.120
Limestone
6.5
0.153
Ceramic board (Fibremax)
0.450
2.2
Horizontal still air (
⅛
"thick)
0.135
0.920**
Example:
Required floor protection R of 1.00. Proposed materials: four inches of brick and one inch of
Durock® board.
Four inches of brick (R = 4 x 0,2 = 0,8) plus 1 inch of Durock® (R = 1 x 0.52 = 0.52).
0.8 + 0.52 = 1.32.
This R value is larger than the required 1.00 and is therefore acceptable.
In the case of a known K and thickness of alternative materials to be used in combination,
convert all K values to R by dividing the thickness of each material by its K value. Add R values
of the proposed materials as shown in the previous example.
Example:
K value = 0.75 Thickness = 1 R value = Thickness/K = 1/0.75 = 1.33
9.3 Minimum Masonry Opening and Clearances to Combustibles
COMBUSTIBLE MANTEL SHELF
COMBUSTIBLE
TOP SURROUND
C
O
M
BU
ST
IB
LE
SI
D
E
SURR
O
UN
D
AD
JA
C
EN
T
SI
D
E
W
AL
L
FLOOR PROTECTION
J
I
H
Q
G
F
K
L
O
P
Figure 26: Masonry Opening and Clearances
www.northlineexpress.com
1-877-734-2458