Technical Data Of Type 100 Movable Partition :
Top Seal (mm)/Pressure (kg)
In architectural acoustics, we are concerned with controlling the amplitude and/or the duration of sound. In walls and partitions, this is done by controlling sound transmission loss and sound absorption.
When sound waves strike a partition, some are reflected from the surface, staying in the same room as the source of the sound. Some are absorbed by the material of the partition, being converted to heat energy. And some are transmitted to the other side.
Sound absorption is the effectiveness of a surface or material at preventing the reflection of sound. It does this by converting sound energy to heat. The more sound absorption, the less echoing will exist. The absorption of a material is measured in Sabines and is found by the equation:
A = .921 Vd/c where
V = the room volume
d = the measured rate of decay in decibels per second
c = the speed of sound
It is important to note the difference between a barrier and an absorber. Typical barriers made of hard, dense material may actually increase the echoes in the room, while absorbent leather of insulation allow sound to pass through as if they weren't there.
Glossary of Acoustical Terms
ABSORPTION - The reduction of reverberating sound by the use of porous, non-dense materials.
AMBIENT NOISE - The ongoing regular noise of a given environment. Also known as background noise.
DECIBEL (dB) - Common unit of loudness, actually a logarithmic ratio of sound pressure level to a reference level.
FLANKING PATH - Leaks in the surrounding construction of a movable partition in which sound can travel. Shoddy construction, customary construction practices, or poor installation of the partition can all contribute to the leaks.
FREQUENCY - The rate of vibration, determining how high or low the pitch is. Frequency is measured in cycles per second, or Hertz (Hz).
HERTZ - Unit of frequency. One Hertz equals one cycle per second. Abbreviated Hz.
NIC (Noise Isolation Class) - This is a number describing the performance of ALL building elements in isolating one room from another. Perhaps the most practical way to state the acoustical performance of movable partitions already installed.
NR (Noise Reduction) - difference between the sound levels in the source and receive rooms.
NRC (Noise Reduction Coefficient) - average of absorption coefficients at four key frequencies. Rating of the absorptive characteristic of a surface.
PINK NOISE - Broadband noise with equal power at each constant-percentage bandwidth, often used for acoustic testing.
RECEIVING ROOM - Room opposite the room with the sound source, in acoustic measurement.
REVERBERATION - The reflection of sound from hard surfaces. Contributes to loudness.
SOURCE ROOM - In architectural acoustic measurements, the room that contains the sound source.
STC (Sound Transmission Class) - the most widely accepted standard for ranking the acoustical performance of accordion and operable partitions.
STL (Sound Transmission Loss) - is the effectiveness of a barrier at preventing sound from getting from one side to the other. It is measured in decibels (dB), the same as amplitude.
ASTM (Formerly American Society for Testing and Materials) - Organization which establishes standards for testing and application in many areas including acoustics.