An acoustical noise declaration is a concise statement about the noise emissions from a product—how "loud" it is, in layman's terms. Technically, there are many ways to describe how loud or how quiet a certain product is, some being very detailed and complex. But in order for a noise declaration to be of any benefit to consumers or prospective purchasers who want to compare one product to another, the information in the noise declaration must be presented in a relatively simple and uniform manner.
Manufacturers and suppliers of Information Technology equipment have agreed amongst themselves to do just that, by developing a consensus international standard that describes precisely how to determine the noise emission levels to declare and how to present the required information to the public. That standard is ISO 9296: Acoustics—Declared Noise Emission Values of Computer and Business Equipment, available at http://www.iso.org (link resides outside of ibm.com). When the requirements of this standard are followed by the declarer, the prospective buyer can be confident that he or she can compare "apples to apples." The noise declaration should state that the noise emissions have been "declared in conformance with ISO 9296."
To make sure the declared levels are accurate as well as uniform, ISO 9296 requires that the noise emission levels must have been measured in accordance with another international standard: ISO 7779: Acoustics—Measurement of Airborne Noise Emitted by Information Technology and Telecommunication Equipment, also available at http://www.iso.org (link resides outside of ibm.com). This standard requires the use of special acoustical test facilities and instrumentation, and specifies in great detail the procedures that must be used to measure the noise levels. In this way, if a given product were measured at different laboratories, each following ISO 7779, the same noise emission values would result. The noise declaration should also state that the noise emissions have been "measured in conformance with ISO 7779."
For more information and background on product noise declarations, the following references may be consulted:
- Nobile, Matthew A. and Eames-Harlan, David, "Web-based product noise declarations," Sound and Vibration, Vol. 38, No. 7, pp. 14-21, July 2004. [Available from Sound and Vibration magazine at http://www.sandv.com/downloads/0407nobi.pdf (PDF, 292KB).]
- Nobile, Matthew A. and Eames-Harlan, David, "Web-Based Product Noise Declarations for the Information Technology Industry," Proc. NOISE-CON 04, 2004 July 12-14, Baltimore, MD, (Noise Control Foundation, Poughkeepsie, NY, 2003). [Available from the Institute of Noise Control Engineering at http://www.inceusa.org (link resides outside of ibm.com)]