ISO 10848 specifies measurement methods to be performed in a laboratory test facility in order to characterize the flanking transmission of one or several building components. The performance of the building components is expressed either as an overall quantity for the combination of elements and junction (such as Dn,f and/or Ln,f ) or as the vibration reduction index Kij of a junction. This part of ISO 10848 contains definitions, general requirements for test specimens and test rooms, and measurement methods. Guidelines are given for the selection of the quantity to be measured depending on the junction and the types of building elements involved. Other parts of ISO 10848 specify the application for different types of junction and building elements. The quantities characterizing the flanking transmission can be used to compare different products, or to express a requirement, or as input data for prediction methods, such as EN 12354-1 and EN 12354-2.