Vermont Castings BFC36 Homeowner's Installation And Operating Manual page 16

BFC36 Balanced Flue Heat-Circulating Fireplace
cordance with Figure 22 and must not cover the bottom
front opening of the circulating model.
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. 21)
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 resistance (Rt).
COMMON MATERIALS AND FACTORS
MATERIAL
EH2416
0.458
Micor 300
Common Brick 5.0
R Value is for 1/2 inch.
* Units of K = BTU/SQ FT/HR/˚F/IN
** Thickness of Listed Material
Fig. 21 Hearth extension material factors.
Example of Determining Hearth Extension Equiva-
FP533ADD
Addendum
lents
6/1/99 djt
To determine the thickness required for any new mate- 8/4/99 changed .2 to .1
one inch to 1/2 inch djt
rial:
NEW K of new material (per inch)
required = --------------------------------------- X
thickness K of listed material (per inch)
Example for Common Brick
T (new) = 5.0/0.458 x 0.50 in. = 5.46 in. (new required
thickness).
16
MINIMUM
K* R
THICKNESS
1.09 0.50 in.**
0.10 5.46 in.**
FP533ADD
thickness
of listed
material
Wall Covering
Noncombustible
Decorative Fac-
ing
Seal all cracks
between fireplace
surround and wall ma-
terials with noncom-
bustible material.
Noncombus-
tible Decorative
Covering
Hearth Exten-
sion Insulation
FP550
Fig. 22 Sealing gaps.
Glass Door Operation
The BFC36 is intended for use only with the doors fully
closed. (Fig. 23)
Correct
Fig. 23 Correct door position.
Side View
2 x 4" Header
- Do not notch at
standoffs
Seal crack between
fireplace and hearth
extension with noncom-
bustible material
Safety Strips -
Must be overlapped 1/2"
minimum
FP550
BR/BC - SEALING
DETAILS
9/29/97
Wrong
KT108b
KT108b
BFC
Correct door position
8/23/00 djt
7412647