OSHA 29 CFR 1910.95 (a) – It’s a Noise Exposure Standard, Not Just a Confusing Number

Strings of numbers and characters can often appear daunting.  For instance, if I wrote in binary code it would be a string of ones and zeros.  (01000101 01101110 01100111 01101001 01101110 01100101 01100101 01110010 01101001 01101110 01100111 00100000 01101001 01110011 00100000 01000001 01010111 01000101 01010011 01001111 01001101 01000101.) That can look like gibberish and cause concern if unknown or it can make sense to programmers and people familiar with binary code.

Other alphanumeric strings may cause some concern for industry professionals.  Take, for instance, OSHA standards. The OSHA standard 29 CFR 1910.95 (a) may be unfamiliar to some, and thus concerning. Many Environmental Health and Safety Engineers will recognize this code.  It is an OSHA standard that revolves around the amount of time an employee is permitted to be exposed to specific sound levels. These sound levels are all based on the weighted sound level of the noise the operators are exposed to. To better understand how the octave and frequency of the sound play into this, there is a chart provided below.

Equivalent A-Weighted Sound Level Chart – (1)

The weighted sound level is the level at which a Digital Sound Level Meter will read the current level of noise within an environment. This scale is then used to move further into the OSHA directive that we focus on helping companies meet to best provide safe environments for their employees to work in.

If you notice, the lowest weighted sound level is 90 dBA, this is also the lowest-rated noise level that OSHA speaks of in 1910.95(b)(2). It has been shown that noise levels over this level for extended periods will result in permanent hearing loss. The standard then goes on to discuss the duration an employee can be exposed to noise levels even with the use of personal protective equipment as well as even impulsive or impact noise.  The table of permissible time limits is shown below.

Permissible Noise Exposures (2)

As you can see from the table above provided by OSHA, any noise level that an operator is exposed to for eight hours cannot exceed 90 dBA. Noises within an industrial environment can also be variable throughout the day. For instance, the operator stands outside of a sheet metal press and the concussive strike on the press gives off a 90 dBA strike for every stroke of the press. This would not be a continuous noise level. Maybe the operator is operating a CNC machine that is cutting a nest of parts and uses a handheld blowgun to remove debris and coolant from the parts before taking them from their fixture. This blowgun is not used continuously and therefore would not be rated as such for the exposure time. A time study would be conducted on the average length of time the operator is utilizing this gun along with the level of noise it produces during use. OSHA then gives a calculation to use to appropriately combine the sound level while the gun is being used and when it is not in use. That equation is written out below.

Mixed Environment Exposure Fraction
C1/T1+C2/T2+… = ____
Total Exposure Fraction
Cn/Tn = ____

Where:
C1 = Duration of time for a specified noise level
T1 = Total time of exposure permitted at that level
Cn = Total time of exposure at a specified noise level
Tn = Total exposure time permitted at that level

Should the summation of the fractions for different exposures be greater than the Total Exposure fraction, the summation value should be used. As mentioned above, a time study on exposure to noise levels will be needed to obtain the information needed for this type of study. Once the study is done the process can proceed to the next level within the OSHA standard which is a hearing conservation program.

I would like to interject a small side-step at this point. Rather than rolling straight into the implementation of PPE which is proven to be the lowest reliable factor of protection by the CDC and NIOSH. If any of these noise levels being generated are due to the use of compressed air points of use, EXAIR can potentially lower the noise of these point of use applications. In the events, open blowoffs or “band-aid” fixes are in place to keep processes running, and Engineered Solutions can easily be implemented that will reduce the noise level produced by this operation. Whether it is on the handheld Safety Air Gun in the hands of a CNC operator, or if it is a part/scrap ejector that is blowing the sheet metal press out after every strike, we have products that have proven time over time using an Engineered Solution will save air, reduce noise levels, and still get the job done.

If you would like to discuss OSHA directives revolving around compressed air, share with us a recent citation you received from an inspector for this standard, or just discuss compressed air usage in general, contact us.

Brian Farno
Application Engineer
BrianFarno@EXAIR.com
@EXAIR_BF

 

1 – Equivalent A-Weighted Sound Level Chart – Retrieved from OSHA.Gov – https://www.osha.gov/pls/oshaweb/owadisp.show_document?p_id=9735&p_table=standards

2 – Permissible Noise Exposures – Retrieved from OSHA.Gov – https://www.osha.gov/pls/oshaweb/owadisp.show_document?p_id=9735&p_table=standards

 

EXAIR’s Efficiency Lab can Help With your Energy Audit, Quantify Savings and Provide an ROI

I recently received an inquiry from a customer to test their current air guns through our Efficiency Lab service. According to the operators, the handheld blow gun they were purchasing from a commercial retailer was too loud and complaints were rolling in.  They were also hoping to save some compressed air in the process as they were performing an energy audit at the same time.

Commercial Air Gun w/ Cross Cut Hole
Commercial Air Gun w/ Cross Cut Hole
Cross Cut Hole Nozzle
Cross Cut Hole Nozzle

The gun they sent in looked fairly similar to our Precision Safety Air Gun but it did not have an engineered nozzle on the tip of it.   Instead, it was simply a cross cut hole in a piece of material.   The air inlet to the gun was a 1/4″ NPT just like our Precision Safety Air Gun, the extension on the gun was slightly longer, the only significant variance I saw was the tip.

EXAIR Model 1410SS-CS
EXAIR Model 1410SS-CS
The Model 1110SS Nao Super Air Nozzle and Chip Shield
The Model 1110SS Nao Super Air Nozzle and Chip Shield

To try and get as much information as possible I measured the O.D. and I.D. of the extension, the hole size was approximately .140″.  I measured the extension on our Precision Safety Air Gun just to see what is different, it came in at the same size.  So, I flow tested the competitive blow gun with their tip on it and came up with air consumption of 12.69 SCFM, noise level of 92 dBA at 3′ away, and a blowing force of 11.5 oz at 80 psig.   I then measured the same attributes of EXAIR’s model 1410SS-CS Precision Safety Air Gun at 80 psig inlet pressure.  The model 1410SS-CS measured 8.3 SCFM, gave 8.1 ozs of working force, and only produced a 75 dBA sound level from 3′ away.

The sound level reduction was a total of 17 dBA which is below the OSHA standard for allowable noise level exposure, as well as reduced their air consumption by 4.39 SCFM.  That is almost a 35% reduction in their compressed air usage per gun replaced.  After seeing these levels of reduction the customer had more than enough information to provide management with in order to replace the blow guns not just for noise level reduction but also because it will reduce air use and save money. A clear supportive role in their energy audit.

If you would like to discuss how EXAIR can provide some free force, flow, and noise level testing for your facility, please contact an Application Engineer or check out the Efficiency Lab page on our site.

Brian Farno
Application Engineer Manager
BrianFarno@EXAIR.com
@EXAIR_BF

Can Fish Hear & Other Noise Exposure Facts?

When I was visiting a supplier in Japan, our host was extremely proud of their koi pond and wanted to demonstrate something. He took us to the pond’s edge and clapped his hands. From the murky depths of the pond emerged huge koi breaking the surface with open mouths. As their reward, he tossed them a handful of fish food.

While everyone else was enamored with his ability to have trained the fish, I was awestruck with the fact that they could hear the sound of clapping deep down into the pond. No wonder dad kept telling me to be quiet or you will scare the fish away.

According to the National Wildlife Federation fish don’t have ears that we can see, but they do have ear parts inside their heads. They pick up sounds in the water through the lateral lines that runs down each side of its body and transmitted to their internal ear.

While human auditory abilities may not be as sensitive as the rest of the animal kingdom, the inner workings of our ears are very sensitive easily damaged. Listening to loud noise for long periods of time can damage the hair cells in the inner ear. Noise-induced hearing loss usually develops gradually and painlessly. We live in a noisy world and hearing loss among Americans is significant. According to the Center for Hearing and Communications, approximately 12% of the U.S. population or 38 million Americans have a significant hearing loss.

For 30 years EXAIR has been designing and manufacturing compressed Super Air Nozzles, jets, knives, and amplifiers that significantly reduce sound levels and compressed air costs. Protect your hearing as well as your employee’s and save money by contacting our application engineers and they will show you how.

Joe Panfalone
Application Engineer
Phone (513) 671-3322
Fax   (513) 671-3363
Web: www.exair.com
Twitter: EXAIR_JP

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Safety – When You Least Expect It You Need it Most

The cold weather kept me indoors this weekend and I conceded to being a couch potato in front of the TV. One of the shows I watched was the lumberjack competitions – and let me tell you, those guys are crazy. Standing on a board wedged into a notch in the side of a tree, up 40 feet in the air and swinging an ax is just not safe. But, that was the way it was done in the early days before mandated safety rules.

Afterward, I watched a little news only to see hundreds of motorists stranded in their cars due to inclement weather. Folks were on their way home from work and ended up sleeping in their cars. I know it is recommended that you carry an emergency kit in your car but I never gave it any thought it would be needed it in the city. Then I was jolted from my couch when the smoke alarms went off. I forgot about my buffalo wings in the oven. Wow! What if I had left the house?

In the workplace, compressed air safety should be a top priority. Open compressed air lines are extremely noisy and can cause permanent hearing loss which is addressed  OSHA Standard 29 CFR – 1910.95 (a) regarding the allowable noise exposure. High pressure compressed air can pierce the skin and enter the blood stream, causing a dangerous blood embolism – this is why OSHA has standard CFR 1910.242(b), 30 PSI maximum dead end pressure for compressed air blow off.

One of the main issues with regulating all of your compressed air lines to less than thirty psig is, thirty psig does not provide a very effective blow off.  With EXAIR’s  engineered nozzles the air can be kept at higher line pressure and still meet or exceed the OSHA standard. Higher pressure equate to higher velocity and more force upon your application. Because of this, we can solve the application, keep compressed air to a minimum, and keep safety a top priority.

Air Nozzle and Safety Air Gun

EXAIR nozzles are safe, provide very effective blow off, and reduce compressed air consumption. By design they produce output flow up to 25 times the compressed air consumed. For more information or help with your application call our application engineers at 1-800-903-9247

Joe Panfalone
Application Engineer
Phone (513) 671-3322
Fax (513) 671-3363
Web: www.exair.com
Twitter: www.twitter.com/exair_jp
Facebook: http://www.facebook.com/exair