high acoustic performances

1.Transmission Loss in Panels The Sound Reduction between two spaces is dependant on all of the elements of the structure separating them. ALL Sound Transmission Paths need to be considered when assessing the total sound reduction. Sound Transmission Loss varies with frequency. The sound pressure waves cause the material to vibrate. It is these movements, which are so small they are not normally visible, which result in re-radiated sound from the panel itself. It can also cause vibrations in supporting members. The sound reduction of a solid wall is frequency-selective as can be seen from the...

The sound transmission loss also varies with the direction of the incident sound waves and is generally assumed to be the average for all possible angles of coincidence. Above the critical frequency, stiffness takes over to give a further though less steep increase in sound reduction. The transmission of sound between rooms involves not only the direct path through the separating assembly, but also the 'flanking' paths around the assembly as well. Stiff panels are needed if high performance is required at low frequencies. Stiff panels however have a lower coincidence frequency, which reduces...

In practical situations, the measured transmission loss often differs from that determined theoretically from the Mass Law. The typical Transmission loss for some common building materials is illustrated in Fig3. As would be expected, the greater mass of the concrete exhibits much higher transmission loss than a sheet of plywood. However, significant deviations from the mass law are evident for all three materials. The curves for plasterboard and plywood (both around 10kg/m2) show very similar transmission loss at low frequencies, increasing steadily in accordance with the mass law. At higher...

1.3. MASS-AIR-MASS RESONANCE There is a practical basis for designing a minimum spacing between cavity layers. When sound waves strike a partition they cause it to vibrate. The air trapped in the cavity between the layers acts like a spring transferring vibration energy from one layer to the other. This energy transfer is significant only in a small frequency range where it causes a sharp lowering of the transmission loss. The frequency of the mass-air-mass resonance depends on• • The mass of the layers and The distance between the layers The larger the air space, or heavier the materials, the...

2. ACOUSTIC WINDOWS The two main types of glass that can be used are: Plate/Float-which is typical glass ranging from 3mm to 25mm thick and Laminated-in which an interlayer of PVB is sandwiched between layers of glass. The noise reduction produced by a barrier is proportional to its mass, area, limpness and air-tightness. As the glass thickness increases the mass will increase. However, at a certain point there will be no more increase in transmission loss due to resonance effects. As the window opening gets bigger, extra glass thickness is more desirable since it will vibrate less in a control...

2.2 SINGLE SHEET LAMINATED GLASS The transmission loss is dominated by the damping at the critical frequency. STC rating Transmission Loss values Fitted STC Contour (blue) of standard 6mm laminated glass. In Fig2 the major difference can be seen between 6mm plate and 6mm laminated glass at 2.5kHz. This is because of the laminated damping interlayer. The bending waves transmitted through the glass cause shear strains within the viscous interlayer material, which in turn transforms the bending waves into heat energy. The laminated glass is less susceptible to excitation by the incident sound waves...

Normal PVB resin Acoustic PVB Fig.3 The example shows the structure of S-LEC® Acoustic Film with 2 outside layers of PVB and an inside layer with significantly enhanced acoustic sound attenuation performance. With 3-layer technology surface quality remains consistent at any location on both sides of the film. 2.2.3 SIGNIFICANT MORE ACOUSTIC PROTECTION THAN STANDARD PVB. Laminated glass already has some noise reducing properties. S-LEC 3-layer Acoustic Film, with its special low elastic resin layer core, delivers significantly better sound attenuation. Sound Transmission Loss of Each Glass Laminate...

In the following table (as a reference) the acoustic performance of some single sheet laminates are shown. ACOUSTIC PERFORMANCE MONOLYTIC GLASS LAMINATED GLASS with S-LEC PVB LAMINATED GLASS with S-LEC SAF Improvement (Indicative) Thickness Rw dB Construction Rw dB Construction Rw dB (mm) + 4 to 5 dB 31 33.1 32 33.1A 36 6 When 31 44.1 33 44.1A 38 standard 8 S-LEC vinyl 31 55.1 35 55.1A 39 10 All values of acoustic blocking have been measured and certified according to the is compared with SAF most recent European norms EN 20717 E DIN 52210. 2.2.4. APPLICATIONS FOR S-LEC ACOUSTIC FILM. S-LEC Acoustic...

the 6mm air-gap. Between 1kHz and 4kHz the critical frequency of the 6mm single pane glass causes it to have a considerably lower transmission loss than the double-glazing. At about 4kHz the critical frequencies of the individual 3mm panes causes the double glazing to be slightly lower than that of the 6mm single pane alone. Near the resonant frequency (250-500Hz) the transmission loss of the double-glazing is actually LESS than that for a single layer of the same glass. At lower frequencies the double glass has higher transmission loss, which is due to the overall doubling of the mass of glass....

The laminated glass consists of two panes of 3mm monolithic glass laminated together with a 0.76mm thick PVB interlayer. As a reference point, the performance of 12mm plate glass is included. It can be seen that the critical frequency dip has been greatly reduced. However, the laminated sections still suffer from resonance effects, which reduce the sound transmission at 150Hz. 2.4.2 ACOUSTIC DOUBLE GLAZING The acoustic performance can be increased further using S-LEC SAF. EXAMPLES OF INSULATING GLASS WITH S-LEC ® SAF Glass All values of acoustic blocking have been measured and certified according...