This part of IEC 61249 gives requirements for properties of modified brominated epoxide woven E-glass reinforced laminate sheets of defined flammability (vertical burning test), copper-clad in thicknesses of 0,05 mm up to 3,2 mm. The flammability rating is acheived through the use of brominated fire retardants reacted as part of the epoxide polymeric structure. The glass transition temperature is defined as being between 150 °C and 190 °C. Some property requirements may have several classes of performance. The class desired needs to be specified on the purchase order, otherwise the default class of material may be supplied