This part of IEC 62607 establishes a method for determining the surface conductance of twodimensional (2D) single-layer or multi-layer atomically thin nano-carbon graphene structures. These are synthesized by chemical vapour deposition (CVD)@ epitaxial growth on silicon carbide (SiC)@ obtained from reduced graphene oxide (rGO) or mechanically exfoliated from graphite [3]. The measurements are made in an air filled standard R100 rectangular waveguide configuration@ at one of the resonant frequency modes@ typically at 7 GHz [4]. Surface conductance measurement by resonant cavity involves monitoring the resonant frequency shift and change in the quality factor before and after insertion of the specimen into the cavity in a quantitative correlation with the specimen surface area. This measurement does not explicitly depend on the thickness of the nano-carbon layer. The thickness of the specimen does not need to be known@ but it is assumed that the lateral dimension is uniform over the specimen area.