Buildings with various noise reduction functions must comply with the criteria provided by the NBN S 01-400 standard.
The NBN ISO 717 standard defines the single-number quantities for the airborne sound insulation in buildings and building elements.
The different sound level spectra of various noise sources are considered to determine these quantities. The single-number values make it possible to determine the quality of the sound insulation and to simplify compiling acoustic performance requirements. The single-number quantities are determined by using the measurements in conformity with the NBN EN ISO 140 standard, so that a model measurement and system can be set. The result in situ may deviate from this.
The calculated single-number quantities are:
Rw = sound insulation of the material tested, in dB, without considering the adjoining materials. Depending on the spectrum of the sound source(s), correction factors can be applied to this.
C = especially for medium and high frequencies,
Ctr = especially for low frequencies (traffic noise).
The single-number value and the correction factor indicated are added together to define the sound insulation of the glass. Displayed as: Rw (C;Ctr)