18
Vermont Castings Stratton
30004508
MA81
Fig. 31
Combustible mantel clearances.
MA81
rev. 8/5/97
*
1
56O
"
Ref.
**
Combustible materials
are permitted within a
shaded area shown in
Figure 28 titled
Minimum Wall
Clearances
* 12” (305 mm) from top of grille opening.
** 6” (152 mm) from top of grille opening.
COMMON MATERIALS AND FACTORS
MATERIAL
K*
R
MINIMUM
THICKNESS
EH2416
Common Brick
0.458
5.0
1.09 1.0 in.**
0.10 10.92 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
Fig. 32
Hearth extension material factors.
FP1202a
EWF30
SEALING DETAILS
6/05
Wall Covering
x 4 Header - Do not
notch at standoffs
Noncombustible
Decorative
Facing
Seal all cracks
between fireplace sur-
round (steel) and wall
materials with noncom-
bustible material.
Face Plate
Noncombustible
Decorative
Covering
Safety Strips - Must be
overlapped 1/” minimum
FP10a
Fig. 33
Sealing gaps.
NoTe: No
material
may cover
black face
plate.
Noncombustible
Material
Side wall protection
Adjacent combustible side walls that are within mini-
mum dimensions shown in Figure 34 of the fireplace
opening must be protected with MHSC Wall Shield
Model SP40 or a specifically built wall shield shown in
Figure 8.
The special wall shield design shown in Figure 8 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 be at least
1.85.
examples of wall shield insulation:
1. Manville - CERAFORM 16, K=.7,
1/ inches thick
. EH416, K = .458,
1 inch thick required.
hearth installation
A hearth extension is required to protect a combustible
floor in front of the fireplace. Refer to Figure 34 for mini-
mum dimensions and mounting detail.
NoTe: hearth extension must not cover the air
inlet opening of a fireplace. The front face must be
able to be removed for servicing.
The hearth extension described in Figure 34 must be a
durable noncombustible material with a minimum (total)
Rt value of 2.18
; see Figure 3 for examples. The
overall height (above a combustible floor), depth and
width must be as indicated, with the extension centered
to the fireplace opening.
The top of insulation must be covered with a non-com-
bustible decorative covering
or
a piece of .018” mini-
mum thickness sheet metal to protect hearth extension
material. (Fig. 34)
Secure the hearth extension to the floor to prevent
shifting. Use trim molding or other similar means at
the three (3) outer edges. Seal the crack between the
fireplace hearth and hearth extension with a noncom-
bustible material. (Figs. 33 and 34)
waRNiNg: hearth extension must be installed in
accordance with Figure 33. Top of hearth extension
must be level with bottom of fireplace.
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 = .18. 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. 3)
T = given thickness
R = thermal resistance for a given thickness (T)
K = thermal conductivity