The testing procedures adopted for evaluating the quality parameters of active hearing protection are listed in the ANSI S-3.19 and CE-EN-352.1 standards. They are used for certifying the ear protection muffs for usage in industrial, construction, shooting (sporting and hunting) and other commercial areas where the level of noise could vary from 90 dB to 164 db and above. In all these cases the selection of materials for production and the design of the product are considered to be highly critical parameters. They determine the quality and product reliability under varying environmental conditions.
Noise Frequency of Active Hearing Protection
The frequency range in which the active hearing protection mechanism is tested varies from 60 Hz to 8000 Hz. The variables used for testing are Assumed Protection Value, Standard Deviation and mean Attenuation values. They are measured under low, medium and high frequency conditions. The value of Assumed Protection Value is derived by subtracting the standard deviation value from the mean value for each frequency. The average of all the mean values can be used to evaluate the quality of ear cup and the foam material used in the ear protection muffs.
- There are many valid reasons for recommending ear muffs rather than plugs or other devices. One of them is supposed to be the coverage and sealing range. By using the muffs for active hearing protection, the rear ear bone region is actively sealed from being exposed to excessive noise levels. As you are aware, the noise levels can be continuous waves within a specific range, varying at odd intervals of time.
- The working of chain saw, industrial machines and other cutting and sawing power driven devices. Impulsive noise is produced by shooting in the sporting and hunting zones. The peak values of these vibrations are called muzzle blasts. They can reach an intensity of 164DB or higher within a time span of less than 3 milliseconds. But these sharp spikes within the noise waves can be highly harmful for the human ear, though their duration lasts only for few milliseconds. In such cases it is critical for the active hearing protection devices to cancel all such spikes of vibrations over extended period of exposure. Since ear muffs cover maximum possible area around the ear including the rear ear, they are highly recommended for multiple types of ear protection applications.
Single Digit Evaluation of Active Hearing Protection
The noise levels generated from gunshots not only produce vibrations of air molecules, but also create high pressure zones around the active hearing protection zone. This is a factor which must be reduced by at least 98% in order to protect the ear and rear ear bone from damages.
The swivel ear cup design which seals the ear bone can actively reduce the pressure to the desired level within a few micro seconds. Coupled with the protective foam pad it can provide maximum protection to ears. Once of the devices which have been found to possess all the above specified features is the ClearArmor 141001 Shooters Hearing Protection Safety Ear Muffs.