Control options
Once you have identified a noise exposure, you need to manage that exposure. Within the safety field we consider a hierarchy of control methods for a given hazard.
Elimination — If it is possible to remove the noise source, which would be the most effective strategy. It is not always possible to do.
Substitution — Changing the noise source to a quieter option. Replacing gas powered lawn equipment with electric lawn equipment is an example of this solution
Engineering Controls — You may be able to isolate the noise source by enclosing it, adding sound barriers, sound absorption material or relocating the noise source to an area that is not occupied. Placing a noise source outside the work area is an effective engineering control
Administrative Controls — can be purposely limiting the exposure time for any person to a level below what the noise standards indicate can cause hearing loss. Putting time limits on noise producing activities can be effective at reducing your exposure. Administrative controls may also include subcontracting the work to a third party. If you do this, you have a duty to warn the other party of the hazard that is present on your premises. If the subcontractor supplies the equipment that produces the noise that was not otherwise present on your premises, the subcontractor will have primary responsibility to protect the hearing of exposed workers.
Personal Protective Equipment (PPE) — provides the exposed person with protective devices that they wear to prevent exposure to hearing loss. The devices can be widely grouped as in ear products, plugs, inserts and over the ear products, headphone, and muffs. This is the most common method of reducing a person’s exposure to noise. This is also one of the least predictable controls as it relies on consistent use and care of the device.
Image courtesy of Michael Pittman – NIOSH
Selecting Hearing Protection
To be effective the hearing protection must be properly fitted, worn properly, and worn whenever they are exposed to a high noise level. PPE used for noise protection are rated with a Noise Reduction Rating (NRR). This is a number that represents the level of noise reduction that the PPE provides. If the product does not have a NRR assigned to it by the manufacturer, it should not be considered an appropriate device for personal protection.
If you know the sound level for the work area in question, you can estimate the effectiveness of the PPE by subtracting 7 from the NRR and that result is subtracted from the measured noise level. This would approximate the noise level under the protective device.
Example – Consistent use of lawn mower - 89 dBA- ear plugs with NRR of 29 would have the 89 reduced by 22 to 67dBA. This should be an effective choice of hearing protection.
For extremely high noise exposures such as gunfire, you may use both in the ear and over the ear hearing protection. You cannot add the two NRR ratings together for a higher NRR. The OSHA Technical Manual allows employers to add 5 dB for the second hearing protector. An example: if wearing an earplug with an NRR of 25 together with an earmuff (also with an NRR of 25), expect a combined NRR of 30. Keep in mind, however, that this rule of thumb is a general estimate.
Use of noise cancelling headphones may be effective if the device has a NRR figure from the manufacturer. If the headphones do not have a manufacturer supplied NRR, they should not be relied on for hearing protection. Use the method above to apply the NRR to the noise exposure to evaluate this type of hearing protection.
Earbuds, headphones, and music to mask noise is a poor choice. You may be compounding the exposure by having a high energy noise source in addition to the environmental noise exposure that already existed. Substituting one high level noise for another does not improve the situation.
Fitting hearing protection
To be effective the hearing protection must properly fit the user. Many foam-based products are one size fits all. There is a specific method to insert these foam devices in your ear. The Centers for Disease Control CDC describes this as the Roll- Pull and Hold method.
Roll the earplugs up into a small thin “snake” with your fingers.
Pull the top of your ear up and back with your opposite hand to straighten out the ear canal. The rolled-up plug should slide right in.
Hold the earplug in place with your finger until it expands to fill the ear canal. Your voice will sound muffled if the plug makes a good seal.
You must use this method to properly get the benefit of in the ear hearing protection.
The Driehaus Difference
Most of the major workers compensation carriers have programs to assist clients with hearing conservation programs. We can help you identify the resources needed to measure noise levels, set up a hearing conservation program and protect your interests with the right insurance program. Call us at 513-977-6860 or contact us via our website at https://www.driehausins.com/. We want to be your insurance provider.
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