Soundproof Glass

While awareness of the importance of protecting oneself from atmospheric and noise pollution is growing, the average noise level in large companies, on busy thoroughfares, and in cities shows no sign of significant decrease. The surest way to guard against the degradation of living conditions caused by annoying noises is to reduce their penetration into the environments where we live and work. Since it is not always possible to act on the sources of noise, it becomes necessary to increase acoustic insulation, ensuring good protection by installing barriers capable of keeping the din out.

To protect against noise, it is possible to install frames with high insulating power, which must be fitted with anti-noise glass to guarantee effectiveness. Depending on the intensity and type of noise, different models of acoustic or anti-noise glass must be chosen to protect indoor environments. Vetreria Re offers its customers a wide variety of anti-noise glass capable of isolating interiors from road traffic, tram clatter, the shouting from markets or public venues open late, airport or station traffic, and noise from large industries or sorting centers.

While it is true that increasing mass increases a glass’s insulating capacity, a simple glass pane—even of considerable thickness—cannot ensure uniform insulation across varying noise frequencies. On the contrary, the use of laminated glass significantly improves acoustic insulation by combining the protective mass of the glass with the insulating action of the plastic interlayer between the panes. Perfect for achieving good insulation against airborne and contact noises, anti-noise glass prevents the penetration of vibrations, acting as a sort of shock-absorbing cushion. It also guarantees high levels of passive safety and protection for people and property, as it is made of robust laminated glass.

Composed of two safety panes joined by a special anti-noise film that increases the glass’s elasticity and ability to absorb vibrations, acoustic insulating glass ensures a noise reduction from the outside that is approximately double that of windows equipped with standard glass. Furthermore, in cases where noise is particularly pervasive, acoustic insulation can be further increased using bonded panels with a sandwich structure, ensuring maximum acoustic silence, a high-quality finish, and superior domestic comfort.

Acoustics in construction is regulated by precise legislation. Specifically, since the entry into force of the Decree of 5/12/1997, “Determination of the passive acoustic requirements of buildings” (March 1998), designers and builders have been obliged to ensure acoustic insulation within buildings using suitable materials capable of reducing the transmission of airborne and impact noise. Respecting these indications during the design phase prevents the need for later interventions—which are often not definitive—and avoids legal disputes and repair costs.

To establish a maximum ceiling for noise levels and impose passive acoustic requirements, the Decree identifies different categories of buildings based on their intended use:

These categories allow for precise parameters to evaluate acoustic characteristics based on:

• Noise of internal systems

• Sound-insulating power of horizontal walls

• Sound-insulating power of vertical walls

To establish the limit values that buildings must respect, reference is made to the following parameters:

Legend:

• Rw (dB): Acoustic insulation of vertical separation elements between distinct housing units.

• D2m,nT,w (dB): Facade acoustic insulation.

• Ln,w (dB): Impact noise level of floors (horizontal).

• LAeq (dB): Sound level produced by continuous internal systems.

• LAsmax (dB): Sound level produced by discontinuous internal systems.

Regarding glass elements, the Facade Insulation Index (D2m,nT,w) is particularly important. The decree requires its consideration for new constructions, renovations, and window frame replacements. To ensure high performance, the insulation of frames, roller shutter boxes, and air vents must be considered. The material insulation index (Rw) is determined by the difference between the noise reduction curve and the reference curve, expressed in decibels.

Beyond the Decree of 5/12/1997, the UNI EN ISO 717-1 standard also governs materials for acoustic insulation, introducing spectral adaptation terms:

• C: index for the pink noise spectrum (TV, HI-FI).

• Ctr: index for traffic-related noise.

In Italy, the European Directive 2002/49/EC was assimilated through Legislative Decree 194 of 19/08/2005, which tasked regions with acoustic planning and mapping to reduce noise sources through soundproofing techniques.

How do you evaluate the acoustic insulation capacity of windows with anti-noise glass? Since windows consist of two distinct parts, the frame affects about 20% of the performance, while the glass affects the remaining 80%. Therefore, to ensure high performance, the insulating capabilities of the frame must be considered alongside the glass.

In contrast, when considering only the acoustic performance of the glazing, the transmission through the frame is not counted; for this reason, the insulation values of the glass itself are always higher than those of the finished window installed on-site. To choose the glass that ensures the best results, one must consider:

• External noise levels (area, traffic, urbanization).

• The intended use of the internal environment (home, office, etc.) and relative reference values from the Decree of 5/12/1997.

• The frames or sashes on which the glass will be installed and their air permeability.

To maximize noise reduction values, it is necessary to increase the surface mass of the material: thicker panes correspond to glass with greater insulating power. However, attention must be paid to the critical resonance frequency, which can reduce the ability to block sound depending on the pane’s thickness. This is why insulating glass units are often made with panes of different thicknesses.

Vetreria Re is available to its selected international clientele to suggest the most suitable solutions for optimal acoustic insulation in private, commercial, or professional settings. With over 20 years of experience in structural glass and prestigious projects in Italy and abroad, Vetreria Re offers cutting-edge solutions to ensure peace, acoustic silence, and comfort.