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 measured quantities 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. This part of ISO 10848 is specifically referred to in ISO 10848-1:2006, 4.4, as being a supporting part to the frame document. This part of ISO 10848 applies to structurally connected light elements forming a T or X junction. A light element is defined in ISO 10848-1:2006, Clause 3. The relevant quantity to be measured is selected according to ISO 10848-1:2006, 4.4. 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. Dn,f and Ln,f depend on the actual dimensions of the elements, while Kij is in principle an invariant quantity. For general application of the test results, Dn,f and Ln,f are the relevant quantities to measure for lightweight, well-damped types of elements (for example, timber or metal framed stud walls or wooden floors on beams), where the actual situation has no real influence on the sound reduction index and damping of the elements. If the acoustical properties of the elements are substantially influenced by the actual situation, Kij is the relevant quantity to measure.