16 |
P a g e
18" min. Non-combustible Hearth
protection required [SEE HEARTH
PROTECTION PAD R-RATING, PAGE 12]
1
1
2
" MAX. THICK HEARTH PAD
(MIN R-1 RATING) IS REQUIRED!
NOTE: For every 1" this fireplace is raised off the floor,
the non-combustible hearth protection pad may be reduced
by 2". If this fireplace is raised off the floor more than 6",
No hearth protection pad is required.
FRONT
FIGURE 8
HEARTH PROTECTION PAD REQUIREMENTS
Hearth Protection R Rating: MINIMUM R-
1 IS REQUIRED. USE OF A ½” THICK (MINIMUM) CEMENT BOARD (Hardi-
backer, Wonderboard or other brand) plus ¼” thick mortar (ThinSet type) plus ¼” thick ceramic tile exceed the R-1 re-
quirement. Use this as a reference, if in doubt. Nat
ural Stones of 1” or greater thickness also exceed R-1 rating.
Hearth Pad Guide- [Usage and Removal]
This fireplace is shipped with a Hearth Pad Guide Installed. The purpose of
the Hearth Pad Guide is to limit the height of the Hearth Pad during instal-
lations. DO NOT build a Hearthpad that is more than 1-1/2” thick. Doing
so will not allow installation of decorative fronts on this fireplace. After the
Hearthpad is built, remove the Hearth Pad guide and discard if you do not
wish the guide to be visible. In some instances, you will want the guide left
permanently, based on your aesthetic judgment.
To remove the Hearth Pad Guide, first remove the Glass Frame. Identify
the plastic Rivet heads inside the fireplace body. Use a sharp utility knife to
pry or cut the plastic rivet head and rivet base. Lift the Hearth Pad Spacer
upwards and remove.
This fireplace may be installed in an elevated position by created an
elevated deck and an appropriate framed enclosure. NOTE: This
fireplace may be elevated but MUST allow a minimum of 72” dis-
tance between this fir
eplace’s floor level and the ceiling.
All hearth pads must be non-combustible (metal, brick, stone, or
mineral fiberboard).
Do not use any combustible material to
protect the floor in front of this fireplace. For the FV41-M, the
hearth protection pad must be rated at R-1 minimum AND it
must extend 18 inches in front of the fireplace face if the
FV41-M fireplace is installed at floor level.
Use the following procedure to determine if a hearth pad meets
the requirements listed in this manual. Find the available values,
R, K or C and follow the formulae below to arrive at a R value.
R-value
= Thermal Resistance
K-value
= Thermal Conductivity
C-value
= Thermal Conductance
Convert the specification to R-value;
a. If R-value is given, no conversion is needed.
b. If K-value is given with for a thickness (t) in inches:
T
K
R
1
...( 1 divided by K , then multiplied by thickness).
c. If C-value is given:
C
R
1
…(1 divided by C).
Determine the R-value of the proposed hearth pad. For multiple
layers, add R-values of each layer to determine overall R-value. If
the overall R-value of the system is greater than R-1, then the
proposed hearth pad is acceptable.
Example:
Required minimum R value for hearth protection pad is R=1. The
proposed alternative is 1/4” tile with a C- factor of 1.25 over 1/8”
mineral board with a K-factor of 0.29. Determine if the proposed
layers will provide the minimum R=1 rating.
Step A.
Use formula to convert C-
factor of the ¼” tile to R-value.
R of the tile:
C
R
1
= 1/1.25 = 0.80
Step B.
Use formula to convert K-factor of mineral board to R-
value.
R of mineral board:
T
K
R
1
=1/0.29 x 0.125 = 0.431
Step C.
Add R values of ¼” Tile and mineral board to get the
Total R-value of proposed alternative:
R
Total
= R
tile
+ R
mineral board
= 0.8 + 0.431 = 1.231.
Step D.
Compare proposed system R = 1.231 to required R
of 1.0. Since R of proposed system is greater than the
required R=1, the proposed system is acceptable.
PRY or CUT RIVET HEAD USING A SHARP EDGE.
REPEAT FOR 4 RIVETS.
Figure 7:
