The science of measurement, embracing both experimental and theoretical determinations at any level of uncertainty in any field of science and technology." The National Metrology Institute of South Africa (NMISA) is responsible for maintaining the SI units and to maintain and develop primary scientific standards of physical quantities for SA and compare those standards with other national standards to ensure global measurement equivalence. It must also provide reference analysis in the case of a measurement dispute and maintain and develop primary methods for chemical analysis to certify reference materials for SA and the region.