Slippery Rock Gazette

Sharon Koehler

Stone Industry Consultant

Stone shops can be noisy places. It’s not a secret. We all know it. There really isn’t much you can do to avoid the noise the tools, saws, forklifts, and trucks make. Not to mention people yelling to be heard over the noise, and the music being played at the top on the volume control to be heard over all the other shop noise.

The EPA recommends no more than 75 decibels over an 8-hour exposure period, or 70 decibels over a 24-hour exposure period. You can safely listen to 80 decibels approximately 40 hours per week. At 85 decibels, you can only listen to that 8 hours per week. At 90 decibels, the time goes down to 4 hours. At 100 decibels, the recommended exposure time is 15 minutes. Anything over these recommended times can result in hearing loss.

The average conversation in an office is 65 decibels. A refrigerator runs up to 47 decibels. A dishwasher goes to about 70 decibels. In your daily non-work life, so far, so good.

But what about your shop life?

• A grinder averages 85-95 decibels. 
  
  
• A CNC when cutting can run up to 120 decibels or more. 
  
  
• A bridge saw, when in use, can go up to 110 decibels, if not more. 
  
  
• A stone drill, even with a muffler system is around 100 decibels. 
  
  
• The average forklift is between 85-100 decibels. 
  
  
• A newer commercial truck averages 100 decibels, more if it’s older. 

That is a lot of noise, probably all at one time, and it can definitely affect your hearing if you aren’t careful.

• The CDC has recommendations for what you can do to help your ears and hearing not to become damaged in loud environments. Unfortunately, the first 2 recommendations aren’t particularly useful for on-the-job noise: 
  
  
• Turning the volume down and walking away from the noise (NOT a very helpful recommendations for a work environ- ment.) However, there are some other recommendations that are helpful:
  
  
• Earmuffs can reduce noise by 25%.
  
  
• Foam earplugs can reduce noise by 50%.
  
  
• Custom earplugs/earbuds can reduce noise by 75%.

Noise-canceling headphones are another great way to drown out noise. However, you must get the right ones. PNC headphones (passive noise canceling) are great for people who work in loud occupations. The thing is that many people find they are uncomfortable to wear for very long. They are designed to envelope the whole ear and can feel tight or heavy. They may take some getting used to.

ANC headphones (active noise canceling) will also reduce noise. However, they don’t drown out sudden noise like car horns and they work better canceling lower frequencies. 

Like anything else, you get what you pay for. The $17 noise canceling headphones won’t do the job nearly as well as a pair you get custom-made, but there are plenty of great over-the-counter headphones in the $100-$400 range. If you prefer, you can get noise canceling headphones that do both PNC and ANC.

How do you know if a noisy workplace is affecting your hearing?

• You have temporary hearing loss after leaving work.
  
  
• You have a ringing sound in your ears after you leave work (tinnitus).
  
  
• You must shout to be heard by a co-worker who is 3 feet or less away.

Are you wondering how loud noise affects your hearing? It’s pretty simple. OSHA actually says it best: “Exposure to loud noise kills the nerve endings in our inner ear. More exposure will result in more dead nerve endings. The result is permanent hearing loss that cannot be corrected through surgery or with medicine. “Noise-induced hearing loss limits your ability to hear high frequency sounds and understand speech, which seriously impairs your ability to communicate. Hearing aids may help, but they do not restore your hearing to normal.” 

According to the OSHA website: The hearing conservation program tries to prevent occupational hearing loss, preserve remaining hearing, and arm employees with the knowledge they need to protect their hearing. The hearing conservation program also helps to educate employers on reducing their noise in one of three ways:

1) Engineering Controls

• Choose low-noise tools and machinery.
  
  
• Maintain and lubricate machinery and equipment (e.g., oil bearings).
  
  
• Place a barrier between the noise source and employee (e.g., sound walls or curtains).
  
  
• Enclose or isolate the noise source.

2) Administrative Controls:

• Operate noisy machines during shifts when fewer people are exposed.
  
  
• Limit the amount of time a person spends at a noise source.
  
  
• Provide quiet areas where workers can gain relief from hazardous noise sources.
  
  
• Controlling noise exposure through distance is often an effective, yet simple and inexpensive administrative control. Specifically, for every doubling of the distance between the source of noise and the worker, the noise is decreased by 6 dBA.

3) Hearing Protective Devices 

You can choose to provide effective noise reduction equipment and ensure employees use it properly.

Our ability to hear is one of our most important assets. You should do all you can to protect it. Once your hearing is lost, you can’t get it back. Hearing aids will help, but unfortunately, once your hearing is gone it’s gone for good.

Please send your thoughts and comments on this article to Sharon Koehler at Sharonk.SRG@gmail.com .

Writers Note: Last month we presented an article about catalytic converter theft. Approximately 2 weeks later Fox News reported that the Oscar Mayer Weinermobile had its catalytic converter stolen while parked at a hotel in Las Vegas, Nevada.

Ahhh, Las Vegas – home of hot slots, hot broads, hot dogs, and hot car parts.