Non-combustible Finished Facing requirements &
Clearance to Combustible Trim
Hearth Extensions:
All STANDARD fireplaces shall have
hearth extensions of brick, concrete, stone, tile or other code
approved noncombustible material. Suitable hearth extension
material for the STANDARD fireplace shall be placed on the
hearth extension’s noncombustible substrate and must extend
to at least twenty inches (20”) in front of the fireplace’s finished
opening and must extend to at least twelve inches (12”) beyond
the sides of the finished fireplace opening.
WARNING:
The noncombustible hearth extension, by code,
must sit on noncombustible substrate which shall have no wood
underpinnings.
This means that off-grade wood floor systems shall be
constructed in such a way that all wood floor joists and sub
-
flooring shall stop twenty inches (20”) out from the front of the
STANDARD firebox.
Mantle and Mantle Shelf Clearances:
STANDARD fireplaces
are subject to the same building code safety clearances to com-
bustible trim as with any radiant heat fireplace.
All combustible trim shall be kept at least eight inches
(8”) from the finished fireplace opening. Combustible trim
located along the sides of the fireplace opening, which project
more than one and one-half inches (1-1/2”) from the face of the
fireplace, shall have additional clearance from the eight inches
(8”) equal to the projection. Combustible projecting mantles up
to twelve inches (12”) of projection - shall not be placed less
than fouteen inches (14”) from the top of the fireplace opening.
Combustible mantles which project more than twelve inches
(12”) from the face of the fireplace, shall have additional clear
-
ance from the fourteen inches (14”) equal to the projection.
Note:
The local authority having jurisdiction may require
greater clearances for projection combustible mantle shelves.
Be sure to check local building codes regarding required
clearances to projecting combustible mantles.
Adjoining Walls.
Side walls and walls to rooms adjoining
STANDARD fireplace installations cannot be closer than
twenty-six inches (26”) to the finished fireplace opening.
(Figure 42)
Note:
“Clearance to Combustible Trim” are those distances
required to ensure that a fireplace mantle or facing will not
catch fire. In most cases the distances should also be adequate to
prevent any discoloration or warping due to heat. However each
installation presents a unique and completely different set of
circumstances involving many variables.
These include paint or finish composition, previous
exposure to heat, methods and quality of construction, air flow
patterns, etc. Because of these variables, the manufacturer does
not guarantee that heat warping or discoloration will never
occur.
25
FIGURE 41
FIGURE 42
