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
This standard provides methods for the measurement of the insertion loss of hearing protection devices in specified continuous and impulsive noise environments.
The microphone-in-real-ear (MIRE) method utilizes human test subjects and may be used for hearing protectors that enclose the ears and make supra-aural or circumaural contact
with the head, whereas the acoustical test fixture (ATF) method employs an inanimate fixture and can be used for any hearing protection device.
The standard contains information on instrumentation, calibration, and electroacoustic requirements including details regarding the sound field of test facilities,
the acoustical characteristics of ATFs, and subject selection and training and location of ear-mounted microphones for MIRE testing.
Methods for measuring or determining sound pressure levels in the ear are also specified as well as methods for reporting the calculated insertion loss.
Methods for Measuring the Real-Ear Attenuation of Hearing Protectors
Specifies laboratory-based procedures for measuring, analyzing & reporting passive noise-reducing capabilities of hearing protection devices. The procedures consist of psychophysical tests conducted on human subjects to determine real-ear attenuation measured at hearing threshold. Two fitting procedures are provided: Method A-trained subject fit and Method B-inexperienced subject fit, intended to approximate protection that can be attained by groups of informed users in workplace hearing conservation programs.
Methods of Estimating Effective A-Weighted Sound Pressure Levels When Hearing Protectors are Worn
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.
Hearing Loss Prevention in Construction and Demolition Workers
This standard applies to all construction and demolition workers with potential noise exposures (continuous, intermittent and impulse) of 85 dBA and above.
Guide to noise control on construction, maintenance and demolition sites (FOREIGN STANDARD)
Provides guidance in noise control in respect of engineering construction, maintenance and demolition works. It covers hearing protection of persons on site, investigation and identification of noise sources, neighbourhood nuisance, measurement of sound and its assessment and control of noise at source and its spread. Appendices provide information on statutory requirements estimation of noise from sites (with examples). A-weighted levels of neighbourhood noise, sound levels from construction, maintenance and demolition plant, remedies and their effectiveness according to machine and source of noise, and use of acoustic screens and enclosures.
Occupational noise management - Hearing protector program (FOREIGN STANDARD)
Specifies administrative responsibilities associated with a hearing protector program; the selection, use and maintenance of various types of hearing protectors; and training and motivation in regard to hearing protector programs.
BS EN ISO 4869-3:2007
Acoustics. Hearing protectors. Measurement of insertion loss of ear-muff type protectors using an acoustic test fixture (British Standard)
ISO 4869-3:2007 specifies a method for measuring the insertion loss of ear-muff type hearing protectors using an acoustic test fixture. The method is applicable to the investigation of production spreads of performance as part of type approval or certification procedures, and to the investigation of the change of performance with age. It is intended to ensure that ear-muff hearing protector samples submitted for subjective testing of attenuation according to ISO 4869-1 have performances typical of the type. The method specified in ISO 4869-3:2007 is not applicable as the basic test for type approval. Performance data obtained by this method are not intended to be quoted as representing the real-ear sound attenuation of an ear-muff, nor the protection provided by the ear-muff.
CAN/CSA Z94.2-02 (R2011)
Hearing Protection Devices - Performance, Selection, Care, and Use
General Clauses 4 to 7 of this Standard cover performance and testing requirements for personal hearing protection devices. Clauses 8 to 12 cover the selection, care, and use of hearing protection devices as required for an effective hearing conservation program.