CCS Hearth & Firebox Components Flashcards

What is the smoke chamber and what is its primary purpose?

Answer: The tapered space above the smoke shelf that compresses smoke before it enters the flue

The smoke chamber is the inverted funnel-shaped space above the smoke shelf that compresses and accelerates combustion gases before they enter the narrow flue.

According to CSIA standards, smoke chamber walls should be pargetted for what reason?

Answer: To smooth the corbeled or stepped masonry surfaces and improve gas flow dynamics

Parge coating smooths out the rough corbeled brickwork in the smoke chamber, reducing turbulence in rising gases and improving overall draft efficiency.

What condition in a smoke chamber is considered a Level 2 inspection finding requiring repair?

Answer: Missing or deteriorated parge coat with gaps exposing masonry joints to flue gases

Deteriorated parge coat exposing mortar joints allows hot flue gases to contact combustible framing through gaps, creating a fire hazard requiring immediate correction.

What is the ideal ratio of flue size to firebox opening area for proper draft performance?

Answer: Flue cross-section should be approximately 1/10 to 1/12 of the firebox opening area

A flue cross-section of 1/10 to 1/12 of the firebox opening area ensures adequate draft velocity without drawing excessive amounts of room air.

What is the throat of a fireplace and where is it located?

Answer: The narrow opening between the top of the firebox and the smoke shelf/chamber

The throat is the constricted opening at the very top of the firebox where the damper plate sits, connecting the combustion zone to the smoke shelf and chamber above.

A smoke chamber that is corbeled outward instead of parged smooth creates what drafting problem?

Answer: It creates turbulence and eddy currents that can cause smoke to spill back into the room

Rough, stepped corbeled walls in the smoke chamber cause turbulence in rising smoke that disrupts laminar flow, increasing the risk of smoke rollout into the living space.