Flue Liner Types & Installation Flashcards

What is the primary reason cast-in-place liners are preferred for irregularly shaped flues?

Answer: They conform to the existing flue shape without requiring demolition

Cast-in-place liners are poured or pumped directly into the existing flue, conforming to irregular shapes and filling voids without major demolition.

Which NFPA standard governs the installation of factory-built chimneys and their liners?

Answer: NFPA 211

NFPA 211 is the Standard for Chimneys, Fireplaces, Vents, and Solid Fuel-Burning Appliances, covering liner installation requirements.

A homeowner reports that their stainless steel liner shows heavy pitting after two years of use with an oil-fired appliance. What is the most likely cause?

Answer: An incorrect alloy grade was used for oil appliance flue gases

Oil appliances produce sulfuric acid condensate that requires a higher-grade alloy; using 316Ti or 316L instead of 304 stainless prevents pitting corrosion.

When sizing a liner for a wood-burning fireplace, the cross-sectional area of the liner should generally be at least what fraction of the fireplace opening area?

Answer: 1/10

A common guideline is that the flue cross-sectional area should be at least 1/10 of the fireplace opening area to ensure adequate draft.

What does the term 'listed' mean when applied to a flexible stainless steel liner system?

Answer: The liner has been tested and certified by a recognized testing laboratory

A listed product has been evaluated by an accredited testing laboratory such as UL and meets published safety and performance standards.

Which installation practice is required when a flexible stainless liner passes through a combustible floor or ceiling?

Answer: An approved firestop spacer must be installed at the penetration

Firestop spacers maintain required clearances and prevent flame spread where the liner penetrates combustible building materials.

A terra cotta tile liner section that has spalled on its interior surface but has no cracks should be classified as:

Answer: Defective and requiring repair or replacement before use

Spalling reduces liner wall thickness and can expose combustible materials to heat and gases, making the liner defective and unsafe for continued use.