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ANSI/ASA S12.68-2007 (R2020)
American National Standards Institute/Acoustical Society of America (ANSI/ASA)
Title

"Methods of Estimating Effective A-Weighted Sound Pressure Levels When Hearing Protectors are Worn"

Description

This standard specifies three methods, in ascending order of complexity of use and potential accuracy, for the estimation of the sound pressure levels that are effective when a hearing protector is worn. The application of the procedures in turn requires an estimate of the real-ear attenuation of the device for groups of users and an estimate of the noise levels to which the users are exposed. The simplest method is the Noise Level Reduction Statistic for use with A-weighting (NRSA) that can be directly subtracted from an A-weighted sound level or sound exposure estimate. A more accurate procedure is the Noise Level Reduction Statistic, Graphical (NRSG) that requires measurements of both the A- and C-weighted sound levels or exposures, and the application of a set of graphical data. Potentially the most accurate approach is the octave-band method utilizing the octave-band real-ear attenuation and noise measurement data. Each of the simplified ratings, the NRSA and NRSG, is to be computed at both the 80th and 20th percentiles to reflect the range of performance to be expected based on the variation in the attenuation data.

Standard Type(s)
Test Method

A definitive procedure that produces a test result: Examples of test methods include, but are not limited to: identification, measurement, and evaluation of one or more qualities, characteristics, or properties. A precision and bias statement shall be reported at the end of a test method.

Personal Protective Equipment
Hearing Protection

All equipment and/or accessories (whether or not detachable) designed and manufactured specifically to protect the ears and ear canal from decibel limits put forth by OSHA. This includes all equipment warn inside or over the ear.

  • Hearing protectors
Hazards
Physical
  • Noise
Standard References
Referenced Standard

ANSI/ASA S12.6-2016 (R2020) - Methods for Measuring the Real-Ear Attenuation of Hearing Protectors

ANSI/ASA S12.42-2010 (R2020) - Methods for the Measurement of Insertion Loss of Hearing Protection Devices in Continuous or Impulsive Noise Using Microphone-in-Real-Ear or Acoustic Test Fixture Procedures

Comments

Additional References:

  • ANSI S1.4, American National Standard Specification for Sound Level Meters
  • ANSI S3.20, American National Standard Bioacoustical Terminology
  • ANSI S12.6, American National Standard Methods for Measuring the Real-Ear Attenuation of Hearing Protectors
  • ANSI S12.42, American National Standard Microphone-in-Real-Ear and Acoustic Test Fixture Methods for the Measurement of Insertion Loss of Circumaural Hearing Protection Devices.

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