What is a Chimney Liner?
A flue lining in a masonry chimney is defined as “A clay, ceramic, or metal conduit installed inside of a chimney, intended to contain the combustion products, direct them to the outside atmosphere, and protect the chimney walls from heat and corrosion.”
Chimney Safety Institute of America Varying from state to state, chimney liners have been highly recommended since the early part of this century, and in fact nowadays many fire codes mandate chimney linings.
Three main functions of a chimney liner according to The Chimney Safety Institute of America (CSIA) (http://www.csia.org/)
- They protect the home from dangerous heat transfer to combustibles.
- Liners protect the chimney structure from combustion byproducts.
- Liners can be sized correctly so your appliance performs at optimum efficiency. Modern appliances require a properly sized flue to create the proper draft. A chimney that is too large or too small will effect the draft.
My Chimney Is Unlined…Is It Safe?
The National Bureau of Standards, also referred to as the NBS, is a measurement research company. They tested unlined masonry chimneys in the 1940’s, and again in the late 1970’s using the facilities of the National Institute of Standards and Technology (N.I.S.T.). At the conclusion of the testing, the N.I.S.T. stated that building an unlined chimney was “little less than criminal.” (www.nist.gov) In addition, according to the NFPA 211 Standard for chimneys, fireplaces, vents, and solid fuel-burning appliances, 2010 edition, “Masonry chimneys shall be lined.”
What Are My Options as Far as Chimney Liners?
- Stainless Steel
- Fireguard Repair System
- Cast In Place/Bladder Pour
Breakdown of each different type of stainless liner
- 304L Stainless Steel Alloy
- This liner is used for solid fuels, such as wood or wood pellets. It is resilient against corrosives and rust.
- 316L Stainless Steel Alloy
- This liner is more resilient against corrosion than the 304L liner, due to the slight change in alloy. Also, it is processed as a low carbon alloy which also makes it more corrosion resistant than the 316. This liner is very good for oil burners, coal stoves and low efficiency gas appliances or non-condensing appliances.
- AL294C Stainless Steel Alloy
- This is the most resilient against corrosion than all the rest. The down side is it is not as good as the 316TI for high flue temperatures. This liner is primarily used for higher efficiency, high-condensing, lower temperature units; to combat the high acidic by-products of these units such as corn burners and high-efficiency gas burners.
Cast In Place/Bladder Pour
Cast in place systems have been used since the 1960’s. This concept originated in Europe and quickly spread to the United States and Canada after gaining respect in the industry due to its versatility and durability. Cast-in-place chimney liners are made of a lightweight refractory material that is cast around a removable rubber balloon. As chimney relining systems go, this system is the best for many reasons. This system is used for almost every type of heating appliance, whether it burns coal, wood, oil or gas. It is designed to withstand extremely high temperatures without cracking or deteriorating.