Appendix 3 Definitions

For a more detailed and technical glossary of terms see ANSI12.60-2006.

Absorbent (sound absorbing) material which is sound absorbing is usually soft and fibrous or cellular and porous. The small air spaces between fibers or within cells “traps” sound and does not allow it to reverberate back into the open space. Examples of such materials include fabric, draperies, foam, acoustical tile, insulating batts or attenuation blankets, acoustical panels, upholstery, etc.

Acoustics the science of sound waves that includes (infrasound, audible sound, and ultrasound)

Acoustical panels manufactured panels designed to absorb specific frequencies of sound waves by “trapping” the energy of the waves within the material; some of the remaining energy is reflected from the surface back into the space, and some is transmitted to the other side.  Panels are available for both walls and ceilings.

Amplification an artificial increase in sound volume created through electronic means

ANSI an acronym for American National Standards Institute

Attenuation (blanket) a soft fibrous device, sometimes with a heavy mass layer inside used to reduce sound levels in a space or the passing of sound through it.

Background Noise Sound in a furnished, unoccupied learning space, including sounds from outdoor sources, building services and utilities. For the purposes of this standard, background noise  excludes sound generated by people within the building or sound generated by temporary or permanent instructional equipment. Noise level or sound level is expressed in decibels, unit symbol dB. In this standard booklet, dB refers to dBA.

Decibel or dB in our case, it is a unit of measurement of the magnitude of the sound level.

Frequency distance between waves depending on the pitch of the sound

IIC  acronym for Impact Isolation Class

OITC  acronym for Outdoor Indoor Transmission Class

NRC  acronym for Noise Reduction Coefficient

Reverberation refers to the persistence of sound in and area or space after an impulse such as a balloon popping.

Separation Wall  the wall between classrooms or between classroom and corridor or classroom and another space.

Sound (sound waves) fluctuations in air pressure that travel from a source to a listener, where they are perceived via the ear and brain as sound. Sound waves behave like light waves; they can be reflected, refracted, diffracted, transmitted, absorbed, and so on.

Signal to Noise Ratio the perceived sound level of the desired source relative to the background noise level (location specific). A minimum signal to noise ratio for good intelligibility of a person speaking is 15dB.

STC  acronym for Sound Transmission Coefficient.

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