Minimum Hearth Extension Requirements - Osburn OB04003 Installation And Operation Manual

Stratford Fireplace Installation and Operation Manual
MATERIAL
®
Micore 160
Micore ® 300
Durock ®
Hardibacker ®
Hardibacker ® 500
®
Wonderboard
Cement mortar
Common brick
Face brick
Marble
Ceramic tile
Concrete
Mineral wool insulation
Limestone
Ceramic board (Fibremax)
Horizontal still air** (1/8")
* Information as reported by manufacturers and other resources.
** For a 1/8" thickness. You cannot «stack» horizontal still air to accumulate R-values; you must separate
each layer of horizontal still air with another non-combustible material.

6.2.4 MINIMUM HEARTH EXTENSION REQUIREMENTS

The hearth extension floor area must extend at least 16"
(41 cm) in front of the hearth (A) and at least 8" (20 cm)
on each side of the door opening (D). The joint between
the hearth extension and the fireplace hearth needs to
be made of non-combustible material such as sheet
metal (not included).
A
B 41.5" (1054 mm)
C
__________________________________________________________________________ 37
Thermal Characteristics of Common Floor Protection Materials*
CLEARANCES
16" (406 mm)
8" (203 mm)
CONDUCTIVITY (k)
PER INCH
0.39
0.49
1.92
1.95
2.3
3.23
5.00
5.00
9.00
14.3 – 20.00
12.5
1.050
0.320
6.5
0.450
0.135
RESISTANCE (R) PER INCH
THICKNESS
2.54
2.06
0.52
0.51
0.44
0.31
0.2
0.2
0.11
0.07 – 0.05
0.008
0.950
3.120
0.153
2.2
0,920**