The acoustics are an important factor of indoor environmental quality (IEQ), and it’s essential that surface finishes and systems be selected to enhance the functionality of any space relative to its design usage. Speech intelligibility is a big concern in classrooms, conference rooms, doctor’s offices, etc., and the choice of ceiling tile and acoustical wall treatment will have a  major effect on noise level and echoing within these spaces. Privacy of conversations is also a real concern in hospitals, clinics, offices, etc., and the choice of ceiling and wall systems will have a significant impact on the amount of sound travelling between spaces.

In many cases, a sound absorbing material (ceiling or wall) will also have a significant sound damping  effect, such that both aspects should be taken into consideration.

Fiberglass Ceiling Panel or Mineral Fiber?

More than 90% of all ceiling panels installed in North America are either fiberglass or mineral fiber with mineral fiber being the more widely used of the two. However, fiberglass is a much more effective sound absorber than is mineral fiber. As such, most every fiberglass ceiling panel is a “Class A or B” sound absorber while most every mineral fiber ceiling panel is a “Class C or D” sound absorber.

Noise Reduction Coefficient – What Is It?

Typically a product’s sound absorption capability is defined by three letters: NRC. This abbreviation stands for Noise Reduction Coefficient and is an arithmetic average (rounded off to the nearest 0.05 of the sound absorption capability of a product at only four frequencies: 250, 500, 1000, and 2000 hertz. These frequencies are representative of the center range of human speech. In order to place this important concept in perspective, one might consider a number of interesting pieces of information:

• Humans can hear sounds from a very low frequency of 20 hertz to an extremely high frequency of 20,000 hertz – far above and below the limited range described by NRC.
• Because NRC is an average of four values, it is certainly possible that two products could have very different sound absorption performance characteristics, yet the same NRC.

The amount of NRC you need really depends on the application and the degree of “quiet” that is desired. A private office doesn’t require as much noise absorption as a first-grade classroom yet, both would be enhanced by a high quality ceiling system. Generally speaking, an NRC of 0.55 is average performance and anything above an NRC of 0.70 is considered good.

Companies use the International Standard for Classification of Sound Absorbers (EN ISO 11654). This standard evaluates products over a wide range of frequencies (200-5000 hertz). It rewards products for high levels of absorption across the entire range of frequencies and penalizes a product for any weak areas of absorption. Products are graded on their individual performance from “A to E” with “A” being the highest class.

Indoor Environmental Quality (IEQ)

Acoustics is an integral factor of indoor environmental quality (IEQ), and it’s essential that surface finishes and systems be selected to enhance the functionality of any space relative to its design usage. Speech intelligibility is of obvious concern in classrooms, conference rooms, doctor’s offices, etc., and the choice of ceiling tile and acoustical wall treatment will have a significant effect on noise level and reverberation within these spaces. Speech privacy is likewise a real concern in hospitals, clinics, offices, etc., and the choice of ceiling and wall systems will have a significant impact on the sound intrusion between spaces.

In many cases, a sound absorbing material (ceiling or wall) will also have a significant sound attenuation effect, such that both aspects should be taken into consideration.

These are the three factors:

1. Absorption
   Sound absorption is the part of the incident sound that is not reflected by the tile.
2. Attenuation
   Sound attenuation is the control of sound transmission between adjacent spaces with a common void above them.
3. Reduction
   Sound reduction is the control of sound generated in the plenum or coming from the floor above.

Whether the concern is speech or noise or sound quality, a combination of sound absorption (surface finishes), sound attenuation (walls, floor, ceiling barriers), and background noise will combine to determine the acoustic performance of the space.

Some spaces such as open offices will do well with a moderate level of background noise for privacy, whereas other spaces such as classrooms will do best with low levels of background noise for intelligibility.

If you want to improve the sound quality in your office or home, talk to Energy Smart Inc. today for more information.