This document specifies the requirements and test methods for flue dampers that are used as components, carrying flue gas, in order to limit the flow in a chimney. Flue dampers may be manually adjusted, sited in connecting flue pipes or chimneys, in order to reduce the burning rate (solid fuel stoves/fireplaces) or to work as a shut-off slide preventing back flow of soot during cleaning of the chimney, or mechanically driven for reducing/closing the flue, in order to reduce the stand-by losses or to prevent the backflow of the flue gas e.g. in case of multi-served chimneys. This document covers only flue dampers incorporated in a housing and installed inside a building. Flue dampers already tested together with system chimney products or other chimney components, e.g. flue liners, connecting flue pipes, are not covered by this document. This document also specifies the requirements for marking, manufacturers instruction, product information, Assessment and Verification of Constancy of Performance (AVCP), cleaning and maintenance.