This Standard 61249-2-23 gives requirements for properties of non-halogenated phenolic cellulose paper copper-clad laminated sheets, economic grade, in thicknesses of 0,8 up to 3,2 mm. This standard covers materials with different requirements on flammability and they are designated to the following: EN 61249-2-23-1 General purpose grade. Requirement on flammability not specified. EN 61249-2-23-2 Materials of defined flammability. (Vertical burning test). This grade of materials provides for one of two flammability requirements as designated as FVO or FV1 as shown in Table 8. Some property requirements may have several classes of performance. This class desired must be specified on the purchase order otherwise the default class of material may be supplied.