Noise-control solutions on the rise

Double-pane glass variants and thicker aluminum profiles are being adopted to improve acoustic insulation ratings.

China suppliers of windows and skylights are gearing product development toward sound reduction, now one of the line’s key selling points.

Effective acoustic insulation has emerged as a key buyer concern following studies linking loud noise to stress, nervousness, insomnia, poor concentration and even cardiovascular ailments. More architects, in fact, are being required to incorporate sound control elements in building design.

To meet demand, manufacturers are combining different forms of acoustic treatments.

Double-pane solutions are the priority since the degree of noise attenuation depends mainly on the type of glass used.

Most companies are tapping laminated variants made of polyvinyl butyral or PVB film sandwiched between two glass sheets. Owing to its viscoelastic property, the interlayer is able to absorb sound waves that penetrate through the first ply of glass. Only minimum noise, as a result, is transmitted to the second pane.

Commonly used in midrange models, PVB glass provides 28 to 34dB of acoustic insulation.

For the high-end segment, enterprises turn to resin-laminated counterparts with a sound protection level of more than 35dB.

Another alternative gaining popularity is insulating glass. Rated at 35 to 60dB, this is preferred in designs meant to reduce high-frequency noise such as those from conversations and amplified music.

Insulating glass similarly adopts two sheets, except the gap is filled with air or gas. The structure prevents sound vibrations from resonating through both panes. Low-frequency noise, however, is not filtered.

Some suppliers are taking a step further with vacuum-sealed versions. In this kind of assembly, the space between the glass plies is evacuated so there is no medium for transmitting sound from the inner to the outer pane. Small support mounts hold the two sheets apart. A low-emissivity coating is applied on the interior faces to keep heat from escaping.

While it provides only 31 to 33dB acoustic insulation, vacuum glass generates the most energy savings. Applications, however, are limited because of its complex manufacturing requirements.

For noise flanking paths, companies are equipping upscale models with PP or PVC seals to close off all possible entry points.

In addition, suppliers are taking sound control into account when producing or purchasing profiles. Aluminum types, for one, are favored over plastic counterparts. The former is heavier and can therefore stop more noise.

To ensure optimum performance, extrusions measuring between 1 and 1.2mm are employed. Thicker than the standard 0.8mm frame, these also improve heat and cold resistance.

The focus and scope of sound abatement efforts vary depending on makers’ individual expertise. More than 40 percent of companies produce mainly aluminum or plastic profiles, while 30 percent specialize in glass manufacture. Other factories are equipped for the fabrication of both inputs.