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1.1 This laboratory test method measures the degree to which reflected sound is attenuated by the most commonly found vertical surfaces in open-plan spaces. Reflection of sound from vertical surfaces is a concern in open-plan spaces because it can reduce speech privacy. The vertical surfaces covered by this test method include wall finishes such as sound-absorbent panels, and furniture panels or screens. It does not cover such items as window finishes or furniture other than panels.1.2 This test procedure was originally developed using the foot-pound system of units for prescribing measurement positions and distances. However, the use of SI units is preferred by ASTM. For this reason, dimensions are provided in SI units, with approximate foot-pound conversions indicated in parentheses.1.2.1 Unless otherwise qualified, all dimensions specified in this test method shall be understood to have a tolerance of ± 25 mm (± 1 in.), even though the indicated approximate conversion of the numerical dimensions given will not always be accurate to this extent. All measurements shall be made in SI units or the corresponding exact foot-pound units.1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

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This specification covers measurement systems used in making sound pressure level measurements in buildings in accordance with ASTM standards and guides. The measurement system includes all the components necessary to indicate measured sound pressure levels, such as microphones, preamplifiers, cables, processing units, filters, computers, display units, and other peripheral devices. Where the system is composed of components, specifications are given for microphone type and orientation, filters and windscreens. This specification does not cover systems for making sound pressure level measurements in other environments, but may include these environments in the future. Performance criteria required for measurement of sound pressure levels in building acoustics are addressed in this specification, along with the requirements for measurements systems which are not designed to conform to a normative sound level meter performance standard.1.1 This specification is for measurement systems used in making sound pressure level measurements in buildings in accordance with ASTM standards and guides. Systems for making sound pressure level measurements in other environments are not addressed in this specification. A future expansion of this specification may include these environments. The systems addressed include one or more microphones and associated components to process the output of the microphone measurement system conforms to a sound level meter specification it is sufficient to specify the category of precision and accuracy required by the measurement system and that direction is given in the user manual for proper use. Where the system is composed of components, specifications are given for microphone type and orientation, filters and windscreens.1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.1.4 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

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