IEC 61249-2-30:2012 gives requirements for properties of non-halogenated epoxide modified cyanate ester woven glass laminate 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.