This NORDTEST method contains supplementary specifications to the measurement procedure stated in ISO/R 354-1963 (E) with regard to measurements on discrete sound absorbers, like noise absorber pads. Noise absorber pads are commonly manufactured as flat absorptive bodies intended for suspension from a ceiling with the flat side vertical.
In practice, some sort of pattern arrangement of noise absorber pads will normally be used when the noise absorber pads are installed in a room. Generally, the absorption of the pads will be influenced by the presence of neighbouring pads, i.e. the absorption will depend on the characteristics of the pattern arrangement and on the absorption capacity of the individual pads.
The present NORDTEST method does not cover test objects like screens which are dealt with in NT ACOU 032, Approved 1981-06.