This part of IEC 61249 gives requirements for properties of non-halogenated phenolic cellulose paper copper-clad laminated sheets, economic grade, in thicknesses of 0,8 mm up to 3,2 mm. This standard covers materials with different requirements on flammability and are designated according to the following: Material 61249-2-23-1: general purpose grade, requirement on flammability not specified, Material 61249-2-23-2: materials of defined flammability (vertical burning test). These grades of material provide for one of two flammability requirements and designated as FV0 or FV1 in Table 8.