Audiometric Calibration and Standards: Introduction
Since the 1950s, an extensive body of specification standards has been created by the British Standards Institution (BSI), the International Organization for Standardization (ISO) and the International Electrotechnical Commission (IEC), giving agreed methods for audiometric testing, reference levels for normal hearing, and minimum performance requirements for audiometric equipment.
These specification standards are essentially national and international agreements which provide a common basis for the conduct of hearing tests and the statement of test results by practitioners and researchers in different medical centres, in different countries. Those dealing with equipment encourage manufacturers to describe the performance of their products in an agreed format, so that the performance of products from different manufacturers can more easily be compared.
Often, as in the case of pure-tone audiometers, equipment is classified by the specification standards into a number of different types or classes, related to its accuracy or specific purpose.
The British Standard should always be used in preference to a differing International Standard, because if it does differ it will do so for good reasons. Nowadays, however, dual-numbering is the norm and such conflicts should become increasingly rare.
In 1997 IEC introduced a new numbering system for all of its international standards, guides and technical reports. A block of numbers ranging from 60000 to 79999 is now used when assigning numbers to its publications making it necessary to add 60000 to the existing base number. Older publications will continue to carry the old series of numbers on printed copies until they are revised, but these publications will appear with the new 60000 numbers when referenced.
Standards relevant to audiometry are presented here, separated under the headings:
- Methods for Audiometry
- Reference Levels
- Audiometers and Impedance Admittance Meters
- Calibration Equipment
- Hearing Aids
- Instrumentation
BSI/ISO/IEC websites
For the most up-to-date information regarding current audiometric standards, as well as pricing and ordering details on all the standards listed here, please contact the relevant standards organisation:
Members of the BSA (British Society of Audiology) can register for the BSA Standards Forum (hosted by NPL), which allows members to view and comment on standards which are currently in development or under revision.
NPL also offers audiometric calibration services, as well as training courses on all aspects of audiometry.