When noise becomes or is anticipated to become an issue, the first proposed solution is generally high STC (sound transmission class) partitions and high CAC (ceiling attenuation class) ceiling systems. However, neither approach is enough because sound easily passes through gaps and holes called sound flanking paths. If these paths aren’t closed, increasing STC or CAC will do nothing to lessen the noise.
This is Reverberation Control
Controlling sound within a room involves managing the reverberation time, which is the lingering of sound in a space that makes it echo-y or too noisy. One factor of the reverberant sound is the cubic volume of the room. However, the other factor is entirely manageable – the amount of sabins, or sound absorbing surface, that is provided by the materials in the room.
Impact Noise Reduction
A key source of noise is activity in floors above the ceiling, as noise travels through the floor structure and radiates into the space below. This is known as impact noise or footfalls, which are measured by a standard called Impact Insulation Classification (IIC).
Fire partitions are rated for 1-hour, and are required as separations for dwelling units in apartments, condominiums and assisted living facilities. They are also required to separate sleeping rooms in hotels and dormitories. These are the same partitions where sound control is desired, and in some cases required by the Code.