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Cashins & Associates Blog

Industrial Hygiene - Hearing Protection Devices

Posted by Eileen Watkins on Fri, Nov, 08, 2013 @ 11:11 AM

NoiseIf you work in a noisy environment - or if your company is required to implement a Hearing Conservation Program because noise exposures exceed an 8-hour time-weighted average of 85 , then you may be using a hearing protection device (HPD).  This article shares some important hearing protection reminders.  It also describes the different types of HPDs and how to use them properly. 

The first thing to remember is that hearing protection devices are the least preferred method of reducing noise exposures.  OSHA requires that engineering and/or administrative controls be investigated first.  HPDs are allowed while these controls are being implemented in the workplace or when they are not feasible.  

If your company relies on HPDs it's important to understand that the success of your hearing protection/conservation program is predicated on choosing appropriate HPDs and ensuring that they are worn properly.

Not only must employers provide hearing protection devices at no cost to their employees and replace those devices "as necessary", but they must allow their employees to choose their HPD from a suitable variety.  OSHA interprets this to mean that at least 1 ear plug style and 1 ear muff style be offered to employees.  While some employers may consider this requirement an inconvenience, it's important to remember that employees are much more likely to comply with any safety requirement when they are regarded as important participants.  In the case of HPDs, your workers are much more likely to wear them if they find them comfortable, well-fitting, and practical.

Disposable ear plugs are probably the most common type of hearing protection device.  They can be preformed or made of moldable foam.  Disposable ear plugs are easy to store and carry, inexpensive, and considered more comfortable than ear muffs in hot, humid work areas.  Reusable ear plugs, including custom-fitted ear plugs, are also available.  They are more expensive and require more care than disposables.  It's easy to wear all ear plug types with other personal protective equipment such as safety glasses and hard hats.

Ear plugs reduce noise exposures by blocking the ear canal.  Proper ear plug insertion is therefore crucial for effective exposure reductions.  The illustration below shows the proper insertion method, which requires you to reach behind your head, pull the outer ear back, then insert the plug.  This technique expands the ear canal and allows for deeper insertion and better blockage of the canal. 


Ear_PlugEar muffs fit over the ears and are constructed with sound-reducing materials that help to reduce noise exposures.  While they are more expensive, heavy, and less portable than ear plugs, they are easy to see (thus making it easy to monitor workers for HPD use)  and sometimes considered more comfortable than ear plugs.  It's important that the headband fit tightly over the head in order to maintain an effective seal around the ears.  Ear muffs can be worn in conjunction with ear plugs when a single HPD is ineffective.  

All hearing protection devices are required by law to have Noise Reduction Ratings (NRRs).  In theory, the NRR represents the decibel reduction that a HPD provides.  The NRRs are determined in ideal, controlled laboratory conditions.  Unfortunately, there is strong evidence that the NRR reduction measured in these settings is rarely achieved in the workplace. 

With this in mind, OSHA recommends that the NRR first be reduced by 7, then further reduced by 50% in order to get a more meaningful NRR - and provide adequate hearing protection to noise-exposed workers.  The equation for this calculation is:

Estimated noise exposure (dBA) = Time-weighted average exposure (dBA) - [(NRR-7) x 0.5] Therefore an ear plug with a NRR of 32 would actually have an effective rating of 12.5. This is a big difference!!

Does your company require the use of hearing protection devices?  Does your hearing conservation program meet OSHA requirements? Do you have current noise exposure measurements?  Cashins & Associates can evaluate your hearing conservation program and other employee safety and health programs, as well.  Click on the button below for your free inquiry.

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Topics: industrial hygiene, hearing loss

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