Image courtesy of Roxul Inc.

Sound Absorbency
The higher density of stone wool insulation contributes to achieving higher acoustical performance than most other insulating materials. Further, the non-directional fiber orientation of the stone wool helps with the absorption of acoustic waves and can reduce the intensity and propagation of noise. Stone wool compositions also have higher densities to effectively reduce airflow and essentially, sound transmissions. These denser structures, coupled with tight, seamless joints create effective barriers to noise and contribute to much quieter and safer work environments.

Acoustical design is based on people's response to sound and noise. Image courtesy of Roxul Inc.

Application for Acoustical Quality
In general acoustic design, noise should be dampened to such an extent that it no longer interferes with the intended activity of the space. Just 30 decibels is disturbing to sleep. Noise with sound levels of 35 decibels or more interferes with the intelligibility of speech in smaller rooms. Even lower background levels are needed for adequate speech intelligibility for vulnerable groups - such as the hearing impaired, the elderly, children in the process of language and reading development, and individuals who are not familiar with the spoken language Rooms with many hard surfaces may result in disturbing 'echo' which must be avoided. A reverberation time below 0.6 seconds is desirable, even in a quiet environment. A 10 dB difference is perceived by the human ear as a doubling (or halving) of the audible sound.

The unique non-directional structure of stone wool insulation is denser than traditional insulations. This effectively reduces airflow and essentially, sound transmissions. Higher air flow resistivity means better sound attenuation. The excellent overall sound control achieved with stone wool batt insulation is also achieved with higher density products rigid and semi-rigid board products.

Green Building Contributions
Stone wool insulation has a number of inherent characteristics that make it intrinsically eligible for US Green Building Council LEED® credits. These include:

• Energy & Atmosphere:
  Energy saving performance through consistently high R-values over time

• Materials & Resources – MRc4 Credit Recycled Content:
  Natural, inorganic materials with a minimum of 75% and up to 93% recycled content available from some stone wool manufacturers.
  
  
• Materials & Resources – MRc2 Credit Construction Waste Management:
  When removed undamaged, stone wool products may be reused and recycled for other projects.

• Indoor Environmental Air Quality:
  Naturally non-combustible without adding undesirable chemicals
  Chemically inert with no outgassing or emissions
  Resistance to growth of mold, fungi, and bacteria
  Will not sustain vermin
  CFC and HCFC free product and process

• Innovation & Design Process:
  Excellent sound absorption for occupants' acoustical comfort
  

  Exemplary performance for MRc4 (Recycled Content) and MRc5 (Region Content)

• Regional Priority Credit (RPc1) for Durable Buildings (Canada):
  Dimensionally stable

Stone wool manufacturing is heavily dependent on recycling. Image courtesy of Roxul Inc.

Application in Buildings
In well-designed buildings, insulation is integrated fully within the envelope design. Generally these systems fall into several typical categories with different stone wool insulation products being well suited to each.