Match your noise character to published glazing data, then prepare a supplier enquiry. Laboratory glass ratings describe the stated build, not the finished room.
Your noise and opening
Interactive
A glazing target from your specifier; not an outdoor-to-indoor noise subtraction.
Mixed or unknown noise: compare all spectrum figures and consider a site acoustic assessment before setting a target.
Identify the existing construction and available depth before selecting a replacement. Keep frame, seals, vents and installation in the assessment.
4 sourced acoustic references match these filters.
April 2020 named Optiphon 6.8 product. Ply split shown for planning mass only; supplier must confirm actual product construction. Whole-opening performance differs.
Assembly and processing conditions
Acoustic data is a lookup for the named product, not a prediction for generic PVB.
Frame, seals, vents and installation affect the finished opening.
Rw is a weighted laboratory sound-reduction index. C and Ctr adapt it to different source spectra: fast transport and speech differ from low-frequency urban traffic, slow trains, distant aircraft or bass-heavy music. Use the source assessment, rather than treating all transport identically.
A change of about 3dB is just perceptible; about 10dB can roughly halve or double perceived loudness. These are general perception guidelines, not a guarantee that a given glass upgrade will halve room noise.
Do not subtract laboratory Rw directly from outdoor sound levels to promise indoor noise. Frame leakage, flanking paths, seals, trickle vents and installation affect the whole opening. Published historical product data needs current supplier confirmation.