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 = ____

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


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


Protecting Employees With PPE vs. Engineered Controls and Substitution

PPE has been a hot topic and new buzzword for a lot of people and throughout many industries over the past 6 months, and rightfully so. When you look at manufacturing though, PPE has been a buzzword for decades. We continue to evolve processes, equipment, and wearables to ensure the safety of operators.  It all boils down to the fact that PPE and the equipment have to be used, and used appropriately in order to be effective.

When reviewing the CDC’s guides for Hierarchy of Controls the least effective method to protect workers is PPE that they must implement and wear/use properly. The fact is, PPE is one of the cheaper entry levels to get to safe working conditions upfront. However, the cost of ownership can quickly surpass more effective methods of providing safe conditions for operators, such as installation of engineered controls or even substituting the hazard w/ engineered solutions.

CDC’s Hierarchy of Controls


So what exactly does that mean to the people on the shop floor? Rather than having to grab a set of pinch and roll earplugs every day on the way through the breezeway to get to the production line, permanently installing quiet products like Super Air Nozzles or Super Air Knives in place of open-ended pipes and drilled pipe blowoffs could eliminate the need for these uncomfortable nuisances. And reliance on personnel to use them correctly, or use them at all is a gamble.

How else can EXAIR help in this pursuit of operator safety and happiness? We offer a free service, the EXAIR Efficiency Lab, which will test your current blow-off products for force, flow, air consumption and noise level. We then recommend an engineered solution if we can improve upon those parameters (spoiler alert, we can) that will meet or exceed OSHA standards for dead-end pressure and allowable noise level exposure.

EXAIR’s Free Efficiency Lab

For this example, installing a quiet product to aid in lowering noise levels can create an environment that no longer needs PPE for protecting personnel. The fix is permanent and eliminates forgotten, lost or broken PPE and the expensive associated with them.

If you would like to discuss any of these options further, please let me know.

Brian Farno
Application Engineer


Video Blog: Meet Brian Bergmann, Application Engineer

Here is a brief video that provides a few details about my background and interests.

To discuss your application and how an EXAIR Intelligent Compressed Air Product can help your process, feel free to contact EXAIR and myself or one of our Application Engineers can help you determine the best solution.

Brian Bergmann
Application Engineer

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Video Blog: Meet Brian Farno

In case you haven’t seen or heard enough of me through the informal videos, here is a brief video that tells a little about myself, my background, and what I like to do outside of work.

Brian Farno
Application Engineer