This part of IEC 61249 gives requirements for properties of bismaleimide/triazine modified with non-halogenated epoxide woven E-glass reinforced laminated sheets of defined flammability (vertical burning test), copper-clad in thicknesses of 0,03 mm up to 1,60 mm. The flammability rating is achieved through the use of non-halogenated inorganic and/or organic compounds acting as fire retardants. These fire retardants are contained as part of polymeric structure or in addition to it. The glass transition temperature is defined to be 160 °C minimum. Some property requirements may have several classes of performance. The class desired should be specified on the purchase order, otherwise the default class of material may be supplied.