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Seasoning - Wood drying (also seasoning lumber or wood seasoning) reduces the moisture content of wood before its use.

Smoke Chamber - Chamber in a fireplace directly above the smoke shelf and extending to the base of the flue.

Smoke Shelf - The area at the bottom of the smoke chamber created as the back wall of the firebox arches forward. The shelf is located at the intersection of the smoke chamber and the firebox. A damper is normally located on the forward side of the smoke shelf.

Soot - A black powdery or flaky substance consisting largely of amorphous carbon, produced by the incomplete burning of organic matter.

Stainless Steel Liners - Stainless steel pipe, either rigid or flexible, made for relining flues of masonry chimneys when the original clay liner has cracked or broken. May also be used to create a lining in a masonry chimney that was made without a clay liner.

Stack Effect - The tendency for warmer air to rise within a structure, creating lower pressure in the lower areas of the building.