Hearth and Home Technologies CB1200I-B - Manual (Page 10)

Page 10 7014-083E September 1, 2008
R CB1200-I Pellet Insert
G. Calculating Alternate Floor Protection Material
Thermal Conductivity: k value
The k value indicates the amount of heat (in BTU’s) that will flow
in 1 hour through 1 square foot of a uniform material 1 inch thick
for each degree (F) of temperature difference from one side of
the material to the other. The LOWER the k factor means less
heat is being conducted through the non-combustible material to
the combustible material beneath it. The k value of a material
must be equal or smaller then the required k value to be accept-
able.
(BTU)
(inch)
(foot 2 (hour) ( o F)
Thermal Resistance: R value
The R value is a measure of a material’s resistance to heat
transfer. R value is convenient when more than one materi-
al is used since you can add the R values together, whereas
you can not do this for k value. The HIGHER the R factor
means less heat is being conducted through the non-com-
bustible material to the combustible material beneath it. The
R value of a material must be equal or larger then the re-
quired R value to be acceptable.
Converting k to R:
Divide 1 by k and multiply the results times the thickness in inch-
es of the material.
R = 1/k x inches of thickness
Converting R to k:
Divide the inches of thickness by R.
k = inches of thickness/R
Calculations:
Example: Floor protection requires k value of 0.84 and 3/4 inch
thick.
Alternative material has a k value of 0.6 and is 3/4 inch thick.
Divide 0.6 by .75 = k value of 0.80. This k value is smaller than
0.84 and therefore is acceptable.
F. Floor Protection
1. Zero Clearance Installations*
It is necessary to install a floor protection of non-combus-
tible material with a R value of 3.0 (1 inch [25mm] minimum
thickness with a “k” value of 0.58) or a 1 inch (25mm) air
space between insert base and hearth.
2. Non-Zero Clearance Installations*
A non-combustible floor protector is required with a mini-
mum R value of 3.0 (1 inch [25mm] minimum thickness with
a “k” value of 0.58) extending 6 inches (153mm) in front of
the insert and 8 inches (203mm) to each side of the door
opening.
* See alternate floor protection worksheet.
E. Masonry Minimum Opening
Location Inches Millimeters
A Rear Width 22 558
B Depth 13 330
C Height - Top Vent 19-1/2 495
D Front Width 29-1/4 743
A
B
C
D