Some people think that if you have a metal chimney liner installed in your masonry chimney that a chimney fire won’t be that dangerous. Let’s first start out by saying that a chimney fire is dangerous no matter what.
What causes a chimney fire?
If a chimney builds up creosote (which all wood burning stoves will do) there is a potential for a chimney fire to start in the chimney liner, whether it is made of metal or masonry/terra-cotta. It is incredibly important that if you burn wood you have your chimney cleaned annually even semi-annually if you burn a lot of wood. Unseasoned wood also will increase creosote build-up dramatically.
How can a metal chimney liner help during a chimney fire?
If a chimney liner is properly installed it can help keep the fire contained in the chimney. Properly installed means, insulated with 1 inch high temperature chimney insulation wrap, or insulation mix. This is not normal insulation. It is specifically designed for a chimney and can deal with temperatures up to 2000 degrees. When a chimney fire spreads to a house it is usually because of cracks in the chimney. Also, the masonry can get incredibly hot and in some cases ignite nearby combustibles.
If you have a metal chimney liner installed and it is insulated this can contain the flames and contain the high temperatures. A metal chimney liner should never be thought of as a device that needs little maintenance. A metal chimney liner must be cleaned just like a chimney without a chimney liner.