- Modern Home Products Corporation Indoor Fireplace User Manual

16
Vermont Castings EWF36A
20005167

1. Manville - CERAFORM 126, K=.27,
1/2 inches thick
2. EH2416, K = .458,
1 inch thick required.

A hearth extension is required to protect a combustible
oor in front of the replace. Refer to Figure 26 for mini-
mum dimensions and mounting detail.


The hearth extension described in Figure 26 must be a
durable noncombustible material with a minimum (total)
Rt value of 1.09; refer to Figure 24 for examples. The
overall height (above a combustible oor), depth and
width must be as indicated, with the extension centered
to the replace opening.
The top of insulation must be covered with a non-com-
bustible decorative covering  a piece of .018” mini-
mum sheet metal, to protect hearth extension material.
(Fig. 26)
Secure the hearth extension to the oor to prevent
shifting, using trim molding or other similar means at
three (3) outer edges. Seal crack between the replace
hearth and hearth extension with a noncombustible
material. (Figs. 25 and 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 conductivity
(K), may be obtained from manufacturer of the material.
Factors are related by the formula K = 1/R. (Fig. 24)
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 sufciently
greater to maintain an equivalent (total) thermal resis-
tance (Rt).


To determine the thickness required for any  mate-
rial:
FP550
BR/BC - SEALING
DETAILS
9/29/97
Wall Covering
2 x 4 Header - Do not
notch at standoffs
Noncombus-
tible Decorative
Facing
Seal all cracks
between replace sur-
round (steel) and wall
materials with noncom-
bustible material.
Cast Front
Noncombustible
Decorative Cover-
ing
Safety Strips - Must be
overlapped 1/2” minimum
FP1202
 Sealing gaps.





COMMON MATERIALS AND FACTORS
MATERIAL K*
R
MINIMUM
THICKNESS
EH2416
Common Brick
0.916
5.0
2.18 1.0 in.**
0.10 5.46 in.**
(CFM Corporation)
R Value is for 1/2 inch.
* Units of K = BTU/SQ FT/HR/˚F/IN
** Thickness of Listed Material
FP533ADD
Addendum
6/1/99 djt
8/4/99 changed .2 to .1
one inch to 1/2 inch djt
FP533ADD
 Hearth extension material factors.
NEW K of new material (per inch) thickness
required = X of listed
thickness K of listed material (per inch) material

T (new) = 5.0/0.458 x 0.50 in. =  (new required
thickness).