InterNACHI Fireplaces, Chimneys & Solid Fuel Appliances 1 — Questions and Answers
Question 1: What is the minimum height a masonry chimney must extend above a flat roof or a roof with a pitch less than 2:12?
- 2 feet above the highest point within 10 feet
- 3 feet above the roof penetration point (Correct answer)
- 18 inches above the ridge line
- 4 feet above the roofline at all points
Correct answer: 3 feet above the roof penetration point
Per the 2-3-10 rule, a chimney must extend at least 3 feet above the highest point where it passes through the roof.
Question 2: Creosote found in a chimney flue is a byproduct of:
- Moisture condensation on cold masonry surfaces
- Incomplete combustion of wood in a fireplace or stove (Correct answer)
- Sulfur deposits from burning natural gas
- Oxidation of the cast-iron firebox liner
Correct answer: Incomplete combustion of wood in a fireplace or stove
Creosote is a flammable, tar-like byproduct of incomplete wood combustion that accumulates inside flue liners and poses a chimney fire risk.
Question 3: What is the primary purpose of a chimney damper?
- To increase the draft velocity through the flue
- To support the chimney liner against thermal movement
- To seal the flue when the fireplace is not in use (Correct answer)
- To prevent downdrafts from entering the combustion chamber
Correct answer: To seal the flue when the fireplace is not in use
The damper is a movable plate located in the throat of the fireplace that closes the flue when not in use to prevent heat loss and block outside air infiltration.
Question 4: According to InterNACHI standards, which component on a chimney directs water away from the junction of the chimney and a sloped roof?
- Flashing and counter-flashing
- Chimney cap with drip edge
- Saddle (cricket) (Correct answer)
- Weep screed
Correct answer: Saddle (cricket)
A saddle or cricket is a peaked structure built behind a wide chimney on a sloped roof to divert water away and prevent pooling and leakage.
Question 5: What is the most common material used to line a masonry chimney flue in residential construction?
- Stainless steel flex liner
- Clay tile (terracotta) (Correct answer)
- Poured-in-place refractory
- Cast-iron segmented liner
Correct answer: Clay tile (terracotta)
Clay tile flue liners are the most commonly installed liner type in masonry chimneys because they are durable, heat-resistant, and cost-effective.
Question 6: A chimney cap serves which of the following primary functions?
- Increasing updraft velocity to improve combustion
- Preventing rain, debris, and animals from entering the flue (Correct answer)
- Reducing thermal expansion stress on the chimney crown
- Meeting code requirements for spark arrestor clearance
Correct answer: Preventing rain, debris, and animals from entering the flue
A chimney cap covers the top of the flue opening to keep out rain, leaves, birds, and small animals while still allowing combustion gases to exit.
Question 7: When inspecting a fireplace firebox, which condition would an InterNACHI inspector flag as a safety deficiency?
- Soot staining on the back wall above the damper shelf
- Cracks in the refractory firebrick panels exceeding 1/8 inch (Correct answer)
- Ash pit door located below the firebox floor level
- Presence of a glass-door screen assembly
Correct answer: Cracks in the refractory firebrick panels exceeding 1/8 inch
Cracks larger than 1/8 inch in firebrick panels can allow combustion gases and heat to escape into the surrounding structure, creating a fire hazard.
InterNACHI Fireplaces, Chimneys & Solid Fuel Appliances 1
What is the minimum height a masonry chimney must extend above a flat roof or a roof with a pitch less than 2:12?