ULC 640

This National Standard of Canada covers lining systems for new masonry chimneys. Liners are for use with gas, liquid and solid fuel fired residential appliances and building heating equipment, where the flue gas temperatures normally do not exceed 650 °C.
Liners are intended for field installation in masonry or concrete chimneys located inside or outside of buildings to provide an essentially vertical conduit or passageway for conveying flue gases to the outer air from the above described class of appliances.