Name: ____________________________ Date: ____________
CAREER INSTITUTE OF TECHNOLOGY
TERMS AND PROCEDURES FOR MASONRY
FIREPLACE
INSTRUCTOR: MR. BRIAN IASIELLO
TERMS
Air-circulating fireplace - A fireplace circulating room air through baffled, heatexchange chambers behind the firebox walls.
Air intake - A passageway for bringing outside air for combustion into the
firebox.
Ash pit - The open space below the inner hearth, inside the fireplace
foundation walls, where ashes are deposited.
Base - Those components of a fireplace including concrete footings,
masonry foundation walls, ash pit, air inlet, and reinforced concrete
hearth base.
Chimney - That part of a fireplace venting combustion byproducts to the
outside air while protecting the house and its occupants from fire
and the life-threatening effects of carbon monoxide poisoning.
Combustion chamber - Also called the firebox, the enclosed space beyond
the fireplace face where combustion occurs.
Cricket - Sloped section of roof designed to divert water from behind the upper
side of a chimney.
Draft - A measure of the passage of air from the firebox to the smoke chamber.
Fire stopping - Also called fireblocking, a noncombustible material preventing air
drafts and the potential spread of smoke and fire
between floors or ceilings.
Firebox - Also called the combustion chamber, the enclosed space beyond
the fireplace face where combustion occurs.
Fireplace surround - The face of the fireplace immediately surrounding the
opening.
Fireplace brick - Also called firebrick, refractory brick that has the thermal
resistance and thermal stability necessary for lining the fireplace firebox.
Flue liner- Available in two foot long, made of fire clay, rectangular or round, is a
hollow chimney lining intended to keep all combustion products and protect the
chimney walls from heat and corrosion.
Hearth - The floor of the firebox.
Hearth base - A steel-reinforced, 4” or thicker concrete slab cantilevered from
the fireplace foundation wall that serves as both the inner and outer hearth
supports.
Inner hearth - The floor of the combustion chamber.
Multi-face fireplace - A fireplace with openings on two or more sides.
Outer hearth - Also called hearth extension, that part of the fireplace extending
beyond the fireplace face in front of the firebox floor.
Rosin fireplace - A single-face fireplace having a curved, back-wall design.
Rumford fireplace - A single-face fireplace design having a tall and shallow
firebox with significantly flared sides and a vertical back for radiating more heat
than a conventional fireplace.
Single - face fireplace - A fireplace having an opening on only one side.
Smoke chamber - An inverted funnel-shaped area extending from the level of
the damper to the bottom of the first flue lining.
Smoke shelf - The area at the base of the smoke chamber, directly behind the
throat damper opening.
Throat - The narrow passage between the combustion chamber and the smoke
chamber.
Throat damper - A cast iron or steel frame and valve plate control that controls
the burning rate by managing the passage of air from the firebox to the smoke
chamber.
Four main parts of a fireplace:
a) The base
b) Firebox
c) Smoke chamber
d) Chimney
A. The base:
1) Foundation or footing- 12” thick and reinforce with rebar
2) Minimum width for the walls of a fireplace base is 8”
3) Ash pit- Ashes from fire can be swept into the ash pit instead of
removing ashes after every fire.
4) Hearth base- supports the firebox floor and the outer hearth floor
extending beyond the front of the firebox.
B. Firebox or the combustion chamber:
1) Hearths- The floor of the fireplace, it can be level with the
floor or elevated to create a raised hearth.
A) Inner hearth- Surface directly under the fire, it forms
the floor of the firebox.
B) Outer hearth - Placed directly in front of the fireplace,
protecting the floor from sparks that may
fall or fly out of the firebox.
2) Firebox- The enclosed space beyond the fireplace face where
the combustion occurs.
A) Firebrick- Refractory brick that has thermal resistance
and thermal stability for lining the fireplace firebox.
B) Ash dump- Built into the firebrick, sweep ashes into
ash pit.
C) Throat- Narrow passage between the combustion
chamber and the smoke chamber.
1. Extends the full width of the combustion
chamber and smoke chamber.
2. The width of the throat of the fireplace is the
same as the width of the damper.
3. Throat damper-Controls the burning rate by
managing the draft
A. Draft- Measure from the passage of
air from the firebox to the smoke
chamber
*Keep damper control closed
when not in use so the hot air
from the room does not go up the
chimney.
C. Smoke chamber- Extends from the level of the throat damper to
the beginning of the chimney flue lining.
1) Purpose is to pass the smoke and any other
byproducts into the chimney
2) When the inside of the smoke chamber is formed
by corbelled masonry, the walls shall not be corbelled
more than 30 degrees.
3) Smoke shelf- Area at the base of the smoke
chamber, directly behind the throat damper.
A) Downdrafts (currents of air that move down
the chimney) are reflected back up the flue
by the smoke shelf.
B) Smoke shelf has a curving or flat upper
surface.
D. Chimney- Vents byproducts to the outside air while
protecting the house and its occupants from fire and life
threatening effects of carbon monoxide poisoning.
**Chimney consists of Units laid around the flue.
Flue liner- Available in two foot long, made
intended to keep all combustion products and
protect the chimney walls from heat and corrosion.