This European Standard specifies the materials, dimensional and performance requirements for precast concrete flue blocks as defined in clause 3 for use in chimneys. The flue blocks may be of single wall or multi-wall construction. This standard does not apply to flue blocks with back ventilation. This standard does not cover products designated wet (W) in conjunction with corrosion class 3. This standard also specifies a type of flue block to dimensionally co-ordinate with masonry unit coursing height, referred to as a type B (bonding block). It also applies to storey-height and flue blocks reinforced for handling.