The American National Standard Methods for Measuring the Real-Ear Attenuation of Hearing Protectors (ANSI/ASA S12.6) explains lab techniques for measuring, examining, and reporting the noise-reducing abilities of ear protectors. The American National Standards Institute (ANSI) developed these procedures with the Acoustical Society of America (ASA), an association that specializes in sound.
What are the ANSI/ASA S12.6 testing methods for hearing protectors?
The ANSI S12.6 defines two approaches to testing. The methods are:
- Method A: Trained Subject Fit
- Method B: Inexperienced-Subject Fit
The main difference is the level of assistance the subjects receive before the tests. Both methods are useful in examining the protector’s performance when worn, but Method B may be more reflective of real people.
With method A, test subjects are trained on how to properly use the equipment before testing begins. The testing consists of the subject fitting the hearing protector before noise is played. They are also told to adjust the protector to increase or decrease the sound.
For method B, the subjects must have no prior knowledge of how to fit hearing protectors. Before the tests, the subjects are given the hearing protector in its packaging and the developer’s written instructions. The subjects must fit and adjust the hearing protector without verbal or physical help. The experimenter may only point out product misuse, such as inserting earplugs backward.
The same testing procedure is performed for method B as is used in method A, with the exception of the difference in training and knowledge beforehand.
Processing the Data
The subjects in both methods are exposed to frequencies of 125, 250, 500, 1000, 2000, 4000, and 8000 Hz. The thresholds, minimum decibels heard by the subject’s ear, are recorded for each frequency. The REAT at each frequency is calculated by averaging the two trials (the difference between the occluded and open thresholds). The NRR is estimated with the overall attenuation mean, which includes the REAT for each frequency and individual results.
Why ANSI s12.6?
Purchasing and using equipment that meets ANSI s12.6 guidelines ensures the utmost safety of yourself and your employees. Proper hearing protection helps to avoid injury or permanent damage to the ears. Defender Safety ear and hearing protection equipment all meets the ANSI s12.6 standard and provides the best protection for your needs in any work environment.