| The principal tests performed in the reverberation chambers involve sound absorption,
sound transmission loss, impact sound transmission, sound power, sound pressure and dB(A)
measurements. RAL tests all kinds of building materials as well as consumer items ranging
from engines to hair dryers. Briefly, sound absorption tests measure the sound level
reduction capabilities attributed to sound absorbing qualities of a specimen. Absorption
coefficients, Sabins and noise reduction coefficients (NRC) are units indicating a
product's sound absorption qualities.
Sound transmission loss tests determine the airborne sound reduction attributed to
barrier elements such as doors, floors, panels, walls and windows. Noise reduction (NR),
transmission loss (TL) and sound transmission class (STC) are units indicating a product's
sound barrier qualities.
Impact sound transmission tests determine the structureborne sound reduction attributed
to a floor ceiling assembly as exposed to an impact device. Normalized sound pressure
levels (Ln) and impact insulation class (IIC) are units indicating a product's sound
insulation qualities.
Various types of floor coverings can be evaluated for their effectiveness at reducing impact sound transmission through a standard concrete floor 6 inches thick.
Reduction in impact sound pressure levels (Lref, c) and the improvement in impact insulation class due to the floor covering (∆IIC) can be determined.
Sound power tests determine the average sound intensity level attributed to sound
sources in watts per unit area. Typical sound pressure tests consist of measurements in
decibels of the average magnitude of sound waves emitted from sound sources. dB(A)
measurements are weighted decibel levels that refer to the response of the human ear to
sound.
RAL Client Confidentiality
Test data collected for a client is considered proprietary and is treated with the highest confidentiality. All research, tests, data, and any additional information attributed to a client, belongs solely to that client and can not be used by any RAL staff member or provided to anyone else for any purpose without the written consent of the client. The RAL staff will not discuss any client's testing endeavors with any non-staff person without the permission of the client. All client documentation is maintained in a client's file and maintained in a secure, locked area where access is only allowed for RAL staff members.
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