17
SHR Series Woodburning Fireplaces
20001384
Side Wall Protection
Adjacent combustible side walls that are within dimen-
sions shown in Figure 29 of fireplace opening must be
protected with Wall Shield Model SP40 or a specifically
built wall shield described in Figure 28.
The special wall shield design described in Figure 25 is
an alternate method of adding protection to side walls
and can be used in place of the SP40 with the same
wall clearances specified for the SP40. Rt must =1.85
minimum.
Examples of wall shield insulation:
1. Manville - CERAFORM 126, K=.27,
1/2 inches thick
2. CFM Corporation - EH2416, K = .458,
1 inch thick required.
40"
Min.
40" Min.
Decorative
Noncombustible
Rigid Covering
Noncombustible
Insulation
R
T
= 1.85 Min.
(Manville Ceraform 126 -
1/2" Thick or CFM
Corporation EH2416 - 1"
Thick)
Fig. 28 Noncombustible wall shield dimensions.
FP838
The top of insulation must be covered with a noncom-
bustible decorative covering or a piece of .018” mini-
mum sheet metal, to protect hearth extension material.
(Fig. 29)
Secure the hearth extension to the floor to prevent
shifting, using trim molding or other similar means at
three (3) outer edges. Seal crack between the fireplace
hearth and hearth extension with a noncombustible
material. (Figs. 29, 31, 32, 33)
WARNING: HEARTH EXTENSION MUST BE IN-
STALLED IN ACCORDANCE WITH FIGURE 26.
Alternate noncombustible materials may be used
providing the (total) thermal resistance (Rt value) of the
alternate material employed is greater than or equal to
R = 1.09. Thermal resistance (R) or thermal conductiv-
ity (K), may be obtained from manufacturer of the
material. Factors are related by the formula K = 1/R.
(Fig. 29)
T = given thickness
R = thermal resistance for a given thickness (T)
K = thermal conductivity
Noncombustible material with a lower R value may be
used, provided thickness of material is sufficiently
greater to maintain an equivalent (total) thermal resis-
tance (Rt).
Example of Determining
Hearth Extension Equivalents
To determine the thickness required for any new
material:
NEW
required
thickness
K of new material (per inch)
K of listed material (per inch)
thickness
of listed
material
=
x
Example for Common Brick
T (new) = 5.0/0.458 x 0.50 in. = 5.46 in. (new required
thickness).
Hearth Installation
A hearth extension is required to protect a combustible
floor in front of the fireplace. Refer to Figure 29 for
minimum dimensions and mounting detail.
NOTE: Hearth Extension must not cover the air
inlet opening of a fireplace.
The hearth extension described in Figure 29 must be a
durable noncombustible material with a minimum (total)
Rt value of 1.09; refer to Figure 30 for examples. The
overall height (above a combustible floor), depth and
width must be as indicated, with the extension centered
to the fireplace opening.
FP533ADD
Fig. 30 Hearth extension material factors.
Common Materials And Factors
Material
K*
R
Minimum
Thickness
EH2416
Common Brick
0.458
5.0
1.09 0.50 in.**
0.10 5.46 in.**
(CFM Corporation)
R Value is for
¹⁄₂
inch.
* Units of K = BTU/SQ FT/HR/ßF/IN
** Thickness of Listed Material
