UL 1777

Chimney Liners

UL 1777

1 Scope

1.1 These requirements cover metallic and nonmetallic chimney liners intended for field-installation into new or existing masonry chimneys that are used for the natural draft venting of Category I gas-fired, Type L vented oil-fired, and solid-fuel-fired residential-type appliances in which the maximum continuous flue-gas outlet temperatures do not exceed 1000°F (538°C).

1.2 Chimney liners are intended to be installed in existing masonry chimneys with or without a liner of fire-clay tile, or to be used as a substitute for masonry fire-clay tile flue liners in new chimneys.

1.3 Chimney liners are intended to be installed in accordance with the Standard for Chimneys, Fireplaces, Vents, and Solid Fuel Burning Appliances, NFPA 211; National Fuel Gas Code, NFPA 54 and codes such as the International Building Code, International Gas Code, International Mechanical Code, International Residential Code, and the Uniform Mechanical Code.

1.4 Chimney liners as covered by these requirements are not intended for use with Category II, III, or IV gas burning appliances as defined by the National Fuel Gas Code, NFPA 54, or other appliances that result in condensation of corrosive acids on the liner of the chimney, or that create positive pressures in the chimney system.

1.5 Chimney liners with cementitious or refractory flue gas conveying conduits shall be evaluated and marked in accordance with the solid-fuel-fired-appliance sections of these requirements.