This part of ISO 717

a) defines single-number quantities for the impact sound insulation in buildings and of floors;

b) gives rules for determining these quantities from the results of measurements carried out in one-third-octave bands in accordance with ISO 140-6 and ISO 140-7, and in octave bands in accordance with that option in ISO 140-7 for field measurements only; and

c) defines single-number quantities for the impact sound reduction of floor coverings and floating floors from the results of measurements carried out in accordance with ISO 140-8.

The single-number quantities in accordance with this part of ISO 717 are intended for rating the impact sound insulation and for simplifying the formulation of acoustical requirements in building codes. The required numerical values of the single0number quantities are specified according to varying needs.

The ratings of results from measurements carried out over an enlarge frequency range is dealt with in annex A.

A method for obtaining single-number quantities for bare massive floors according to their performance in combination with floor coverings is described in annex B.

An example of the calculation of a single number quantity is given in annex C.