A flue lining in a masonry chimney is defined as "A clay, ceramic, or metal liner.
The chimney is one of the most taken-for-granted parts of a home. Typically it tends to receive neither the attention nor the concern usually accorded other household service systems. The fact that chimneys may do their job reasonably well, even when abused or neglected, contributes to this atmosphere of indifference. Chimneys are far from the passive black holes that most people assume them to be. They perform several vital functions, and their simple appearance misrepresents their complex construction and performance requirements. A chimney deteriorated by constant exposure to the weather can be a potential safety hazard. Weather-damaged lining systems, flue obstructions and loose masonry materials all present a threat to residents. Regular chimney maintenance is essential to prevent damage, deterioration and future high-cost chimney repairs.
National Fire Protection association states the following:
Damaged or deteriorated liners:
If the flue liner of a masonry chimney has been softened, cracked, or otherwise deteriorated such that it no longer has the continued ability to contain the products of combustion, i.e heat, moisture, creosote and flue gases, it shall be either removed and replaced, repaired, or relined with a listed liner system or other approved material that will resist corrosion, softening, or cracking from flue gases at temperature appropriate to the class of the chimney service.
A Stainless Steel chimney liner is air and water tight. It locks in moisture and flue gases in your chimney and keeps them out of your home. This unique alloy is designed specifically to resist acids coming from gas appliances in the flue and extreme stresses of hot and cold cycles. Stainless Steel 316Ti liner has been UL Tested under the most extreme conditions including multiple simulated chimney fires exceeding 2100 F so you'll sleep soundly at night knowing that your home is safer for yourself and your family.
Liners in chimneys serve three main functions: