Installation of Absorbents
The amount, location, and installation method for absorbents are all significant in a room. As discussed in Art. 11.79.6, the material is located on surfaces from which reflections are undesirable and where it is reasonably free from damage. The amount of material required can be determined from noise-reduction and reverberation-time calculations. (For most simple spaces, a full ceiling treatment is acceptable.)
Acoustical absorbents can be cemented directly to a smooth, solid surface, nailed or stapled to furring strips, or suspended by any of a number of mechanical systems, such as that shown in Fig. 11.100.
While acoustical absorbents are usually installed as, or on, flat, horizontal surfaces,
various other configurations are used. Coffers, grids of hanging panels, and similar are often employed. The acoustical performance of each configuration must be tested to determine its effectiveness.
Sprayed-on and trowel-applied acoustical products are also employed, although their use is limited.
The structural, fire-resistance, and acoustical performance of most acoustical panels and tiles are significantly affected by the installation method. It is imperative that performance data be explicitly related to the specific installation method.
Partition Bypassing. When partitions or other sound barriers are constructed to (but not through) a suspended acoustical tile or panel ceiling, sound transmission through the tile from one space, over the top of the partition, into an adjacent space can be a serious annoyance. Figure 11.101 shows how sound can bypass a partition, and alternative methods of preventing this.
Similarly, structure-borne flanking transmission along the continuous metal runners of some suspension systems may seriously degrade the performance of an acoustical ceiling as a sound barrier. Performance data for most typical commercial ceilings are published in various bulletins and advertising matter.
