This European Standard specifies the materials, dimensional and performance requirements for straight concrete system chimneys for balanced flue applications comprising a concrete flue liner and a combustion air supply duct, and a combination of compatible chimney components, which may be concrete flue blocks (see clause 4), obtained or specified from one manufacturing source with product responsibility for the whole chimney. The standard does not apply to concrete system chimneys with back ventilation. This standard does not cover products designated wet (W) in conjunction with corrosion class 3. This European Standard also applies to concrete system chimneys constructed from storey-height elements and flue blocks reinforced for handling. NOTE Any reference to the term flue blocks implies both flue blocks and their fittings, except where otherwise indicated.