The international standard ISO 20189

describes how different furniture products should be evaluated and declared regarding acoustic performance, with focus on the final user. It describes which furniture that can be evaluated with sound absorption factor, sound absorption area per object and what types of screens that can be evaluated with sound level reduction.

The essence of the standard is

that products that in practice are not used as large surfaces should be evaluated with their sound absorption area per object. Only objects larger than 10 square meters can be declared using the absorption factor. This means that small objects cannot be evaluated using absorption classes.

The same applies to sound level reduction

which can only be used for declaration of floor-standing screens. Table screens cannot be declared with sound level reduction as they are too low in effective screen height.

The absorption area per object is evaluated in the individual octave bands 125, 250, 500, 1000, 2000 and 4000 Hz, and the values are calculated from the sound absorption areas in the corresponding 1/3 octave bands.