Hearing Protection Devices

Hearing protection devices, or HPDs, are your best defense when you are unable to reduce your exposure to loud noise levels.  When worn properly, hearing protection can greatly reduce the decibel level that reaches your ear.  HPDs act as barriers to reduce sound entering the ear.  They are very important, in that they decrease the risk of excessive noise exposure and subsequent hearing loss.

There are three basic types of hearing protection devices:

• ear muffs
• ear plugs
• canal caps

Each of these types will be discussed in greater detail in the next three slides.

An important concept to understand regarding HPDs is the assignment of a Noise Reduction Rating, or NRR, for each type of device.  The NRR is a number that indicates the degree to which that device reduces your noise exposure.  In the example to the right, these ear muffs will reduce the noise level you perceive by 25 decibels if strap is worn over the head, 24 decibels if worn behind the head, and 23 decibels if worn under the chin.

Let's discuss ear plugs in more detail.