This document specifies the performance requirements for rigid or flexible metal flue liners, rigid metal connecting flue pipes and their fittings used to convey the products of combustion from appliances to the outside atmosphere (including their supports). Vitreous enamelled connecting flue pipes are also covered by this document. Rigid flue liners can be used as flue liners for renovation or adaptation of existing chimneys and as flue liners of custom built chimneys. Flexible metal flue liners described in this document are exclusively for renovation or adaptation of existing chimneys. Flexible connecting flue pipes and extensible flexible products designed to be compressed or extended along their length are excluded from the scope of this document. This document also specifies the requirements for marking, manufacturer's instructions, product information and evaluation of conformity. Single wall and multi-wall system chimney products are covered by prEN 1856-1.