Hearing protection devices, such as ear plugs and earmuffs, are given a Noise Reduction Rating (NRR), unit of measurement, to determine their effectiveness in decreasing exposure to sound. The ability to reduce noise and sound is measured in decibels (dB) which is used to classify a given ear plug or earmuff and provide an associated NRR. The American National Standards(ANSI) and the Occupational Safety & Health Administration (OSHA), provide testing and approval metrics for manufacturers to follow,so they can appoint the appropriate NRR class for a particular hearing protection item or device.

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How do NRR levels change the exposure to noise decibels?

When wearing hearing protection, the level of exposure to sound is directly related to the NRR rating of the specific ear protection product you are using. However, even though the NRR’s are measured in decibels the amount of protection provided does not reduce the level of sound or noise that is in the users environment by that specific rating amount. I.e. if you are working on a construction site and the level of sound exposure is 100 dB and the earplugs or earmuffs you are wearing have an NRR of 33dB, your level of exposure would not be reduced to 67dB. To find the actual level of sound protection, it is necessary to take the NRR decibel number, minus seven, divided by two. The construction site example mentioned above would thus look like this: (33-7) / 2 =13, therefore the actual level of sound exposure would be 100dB – 13dB = 87dB.

*In order to maximize noise reduction and hearing protection, ear plugs and earmuffs must be worn properly.

Can I wear dual hearing protectors and Increase the NRR?

Absolutely! Wearing earplugs and earmuffs at the same time is a great way to ensure that you are protecting your hearing and ears as best that you can. However, it is important to note that when determining the new NRR level of noise protection, one does not add the two ratings together, but rather you add 5 additional decibels of protection to the device that has the highest NRR and thus come up with the new combined NRR. I.e. if using the 3M™ E-A-R™ Classic Earplugs that have a NRR of 29, with the 3M™ Peltor™ H7 Deluxe Earmuffs (that have a NRR of 27, you would achieve a new total Noise Reduction Rating of about 34 decibels, or (29+5=34).

What Does OSHA Consider Excessive Noise?

Various testing instruments and devices are able to measure sound exposure in any given work environment or condition. OSHA generally defines exposure to 85dB of sound or more for periods of 8 hours or more to be excessive. In this type of environment, it is required that employers provide hearing protection for their employees. The decibel level of a particular environment determines the OSHA Action Level necessary and each hearing protection device must meet the ANSI S3.19-1973 NRR test levels.

If the sound levels in an environment exceed the values shown in the chart below, a certified, effective hearing preservation program should be implemented.

Below are few common situations and associated decibel levels that OSHA has defined as being potentially harmful to your ears and hearing: lawnmowers, tractors, music concerts, guns, fireworks, headphones, motorcycles, drilling equipment, ATV’s, chain saws, power tools and industrial equipment and machinery. It is strongly suggested that you use hearing protection devices when working (or playing) in environmentswhere noise and sounds commonly exceed 90 decibels.

Painful:

150 dB = Rock or Music Concerts at Peak
140 dB = Guns, Tornado warnings, Air-Raid Sirens, Jet Engines
130 dB = Jackhammers, Drilling Equipment
120 dB = Airplane Take-off, Amplified Music at 4-6 ft., Car Stereo, Band Practice, Drums

Extremely loud:

110 dB = Equipment or Machinery, Model Airplanes
100 dB = Four Wheelers, Three wheelers, Snowmobiles, Chain saws, Pneumatic Drills
90 dB = Trains, Lawnmowers, Shop Tools, Truck Traffic, Subway

Very loud:

80 dB = Alarm Clocks, Busy Street Traffic
70 dB = Vacuum Cleaners, Power Washers, Weed Trimmers
60 dB = Conversation, Dishwashers, Furnaces, Washing Machines, Dryers

Moderate:

50 dB = Moderate Rainfall, Chirping birds
40 dB = Quiet room

Faint:

30 dB = Whisper, Quiet Library, Courtroom

How to Save Your Hearing

To avoid permanent damage to your hearing and ears it is recommended that you avoid exposing yourself to environments that produce high decibel sound levels. If it is necessary for you to be in that environment, please protect your hearing and ears with the proper hearing protection earplug or earmuff hearing protector. If you have additional questions or concerns about the ear protection products on our website, please reach out to our customer service department and our dedicated staff will be happy to assist you and answer any questions you may have regarding hearing safety and noise reduction.