Understanding NRR and Hearing Protection

Why is it important?

When selecting an earplug or earmuff, it is helpful to monitor the level of noise to know how much protection is needed. It is also very useful to understand some of the basic terminology and the noise reduction rating of products in order to pick the right hearing protection.

NRR Ratings

The performance of earplugs and earmuffs varies between brands and styles. One way to choose a hearing protector is to compare Noise Reduction Ratings. The Noise Reduction Rating, or NRR, measures the muff's or plug's ability to block out noise or "attenuate"; sound. This measurement is stated in decibels; a plug with an NRR of 26 blocks out a maximum of 26 decibels of noise. The NRR listed is the maximum protection that could be achieved if the plug fit the wearer perfectly and was inserted correctly. In most work situations attenuation is half of the listed NRR. For example, if the NRR is 30 the hearing protector most likely blocks out 15 decibels of noise.

All of the earplugs and muffs we stock have been tested by an accredited laboratory that assigned an NRR rating. As you look through our selection, look for the NRR rating by each style of protection.

How damaging are your work activities?

Common Sound Decibel Rating

Lowest audible sound  

0 dB

Quiet empty barn, babbling trout stream, gentle breeze

50 dB

Normal conversation

60 dB

Chicken coop, farrowing area

70 dB

Tractor or combine idling, barn cleaner, conveyor, elevator: You can begin to lose your hearing at this dB if you're exposed to it for eight (8) hours or more per day.

85 dB


Blower compressor, pneumatic wrench, chopping silage (no cab), full-throttle mower: If you are exposed to noises at this level for four (4) hours or more per day, hearing loss can occur.

90 dB


Tractor at 80% load, squealing sows, power tools, hand-held metal grinder: One hour of exposure per day is the limit at this decibel level.

100 dB


Full-throttle combine, 10-HP vane-axial barn fan: Anything over 15 minutes exposure per day can cause damage.

110 dB


Thunderclap (near), sandblasting, bad muffler, old chain saw: The danger is immediate.

120 dB

Gunshot, engine back-fire, dynamite blast, jet engine. Any length of exposure time is dangerous and may actually cause ear pain.

140 dB


As noise gets louder, damage can occur sooner. There is no "cure" for hearing loss. This chart is only a guideline. Anything over 85 dB can be damaging to your hearing.
Chart provided courtesy of the National Farm Medicine Center

How do you know if noise is damaging your hearing?

You may have a problem if you:

  • Hear ringing, other noises or a fullness in your ears
  • Can't hear people when they talk to you
  • Can't hear high pitched or soft sounds

What hearing protection is best for me?

All hearing protection equipment has pros and cons. Not one hearing protection device is best for all operations. Skim this list of pros and cons below and then apply it to your operation. Weighing cost, ease of use and protection

Disposable Ear Plugs


Fits many different ear canals

Usually has higher NRR compared to other protective devices

Initially less expensive compared to others

Maintenance free; can toss instead of clean


Can be difficult to insert

If not properly inserted, you may not get the highest NRR possible

More expensive over time

Reusable Ear Plugs


Easily inserted and worn

More economical over time compared to disposable plugs


Pre-formed so does not fit as wide a variety of ear canals as disposables

Must take time to clean to avoid infection

Earmuffs and Stereo Earmuffs


Easy to use and wear

Can get stereo muffs, which makes working more fun and comfortable

Requires less training to use correctly compared to plugs

More economical in the long run compared to earplugs


Needs more storage space

Must take time to clean to avoid infection

Sometimes gets more uncomfortable in warmer weather compared to plugs

Can make wearing other PPE such as glasses more cumbersome