Types of Steel Tubing for Fireplace Inserts

Chimney Liners

• A stainless steel liner needs to be used when installing a new fireplace insert. While you can use the old chimney, it must be properly relined in order to deal with the new fireplace exhaust. The easiest way to do this is with stainless steel piping designed specifically for fireplace inserts. While a number of different pipe types are available, you must use a steel chimney pipe or liner rated for and consistent with your fireplace insert type.

Steel Chimney Liner Size and Types

• The size of the steel pipe for your insert will depend on the size of the collar on the fireplace insert. Steel chimney liners are typically available in 6- or 8-inch diameters. But the exhaust and supply pipes do not need to be tube-shaped in order to work. If you are using oval piping in your system, there are multiple options available. Consult your fireplace insert installation guide for more specific information. The steel tubing must also be rated for the type of heat created, such as gas, wood or electric.

Rigid or Flexible Steel Chimney Liners

• Steel fireplace insert tubing can be either rigid or flexible. Flexible sections help navigate strangely shaped chimneys. The rigid lengths of pipe are for areas where you have a clear shot through the chimney. Insulation is an important part of either option, and building codes often require insulated chimney pipe between chimney walls and rigid piping, if the chimney is made of flammable materials. This prevents heat from passing through the tube and into more flammable parts of the chimney.

Fireplace Insert Collar

• When relining the chimney, the collar is a piping component that connects the steel chimney liner to the fireplace insert. Collars atop the fireplace insert or in the back allow the insert and its piping to form an airtight connection, preventing any dangerous exhaust from escaping. Follow instructions when attaching the steel chimney tubing to the collar. Use high-temperature caulk if you seal the collar connection to prevent heat and air flow.