Hearth and Home Technologies C-40 Indoor Fireplace User Manual


  Open as PDF
of 72
 
Page 38
Heatilator • Constitution EPA Fireplace • 480-1091C
November 11, 2008
8
Finishing
A. Hearth Extension
Ahearthextension mustbeinstalledwith allreplacesto
protectthe combustibleoorin frontof thereplacefrom
both radiant heat and sparks. See Figures 38.1 below, and
Figures 40.1 and 40.2 on page 40.
2 in. (51 mm)
required
Hi
g
h
temperature
(300°F min.) continuous,
non-combustible sealant
Tile, stone or other
non-combustible material
Floor constructed of wood or
o
th
e
r
co
m
bus
ti
b
l
e
m
a
t
e
ri
a
l
HX3 or HX4
Hearth Ext
or equivalent
insulation
(see Table below)
Fireplace
Protective
Metal Hearth
Strip
Figure 38.1 Hearth Extension Construction
Table 38.2
B. Calculating Alternate Floor Protection
Material
Thermal Conductivity: k value
Thekvalueindicatestheamountofheat(inBTU’s)thatwillow
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 mate-
rial must be equal or smaller then the required k value to be
acceptable.
(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
material 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-
combustible material to the combustible material beneath it.
The R value of a material must be equal or larger then the
required 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.
Fire Risk
• Maintainclearances.
• Use only non-combustible material below
standoffs, material such as cement board
is acceptable.
WARNING
• Framingornishingmaterialusedonthefront
of, or in front of, the appliance closer than the
minimums listed, must be constructed entirely of
noncombustible materials (i.e., steel studs, concrete
board, etc.).
Hearth Extension Insulation Alternatives
Minimum R Value = 2.18
Material
k per inch
thick
R per inch
thick
Minimum
thickness
required
Hearth & Home HX3, HX4 0.49 2.18 1 in.
USG Micore 300™ 0.49 2.18 1 in.
USG Durock™ Cement Board 1.92 0.52 2-1/4 in.
Cement Mortor 5.0 0.20 5-7/8 in.
Common Brick 5.0 0.20 5-7/8 in.
Ceramic Tile 12.50 0.08 14-5/8 in.
Armstrong™ Privacy
Guard Plus 0.46 2.18 1/2 in.
Marble 14.3-20.0 0.07-0.05 16-5/8 in. - 23-3/8 in.
 previous next