Tag: noise exposure

Reducing Pneumatic Exhaust Noise with EXAIR Mufflers

Published on by Jordan T ShouseLeave a comment

In many manufacturing facilities, compressed air systems are one of the largest contributors to workplace noise. Pneumatic cylinders, valves, vacuum generators, and cooling devices all exhaust compressed air, often creating sound levels high enough to require hearing protection. OSHA Standard 29 CFR 1910.95 outlines permissible workplace noise exposure levels, making noise reduction an important part of maintaining a safer and more comfortable work environment.

To help solve these issues, EXAIR offers several different styles of Silencing Mufflers designed for specific applications. Choosing the correct muffler can improve operator safety, reduce exhaust noise, and even help eliminate oil mist from compressed air systems.

Reclassifying Mufflers – Maximum Noise Reduction and Oil Removal

Reclassifying Mufflers are EXAIR’s most advanced muffler option. These mufflers are designed not only to reduce noise, but also to remove oil mist from exhausted compressed air. In pneumatic systems where lubricated air is used, exhausted oil mist can create slippery surfaces, contaminate products, and affect air quality.

EXAIR Reclassifying Mufflers can reduce sound levels by up to 35 dB while separating oil from the exhaust stream through a removable filter element. The collected oil drains into an integrated reservoir, helping facilities maintain cleaner and safer operations.

These mufflers are ideal for:

  • Pneumatic cylinders
  • Air valves
  • Lubricated compressed air systems
  • Applications where oil mist must be controlled

Sintered Bronze Mufflers – Simple and Cost Effective

Sintered Bronze Mufflers are a popular low-cost solution for reducing exhaust noise from pneumatic equipment. Their porous bronze construction allows compressed air to pass through with minimal back pressure, helping maintain proper equipment performance.

These mufflers are:

  • Easy to install
  • Available in a wide range of sizes
  • Ideal for standard cylinder and valve exhausts
  • Designed for minimal airflow restriction

Unlike Reclassifying Mufflers, Sintered Bronze Mufflers do not remove oil mist from the exhaust air. However, they remain an excellent option when a simple and economical noise reduction solution is needed.

Straight-Through Mufflers – Ideal for Remote Exhaust Applications

Straight-Through Mufflers are designed for applications where exhaust air needs to be piped away from operators or sensitive areas. These mufflers feature a corrosion-resistant aluminum shell lined with sound-absorbing foam and can reduce noise levels by up to 20 dB.

Their threaded inlet and outlet design makes them especially useful for:

  • Vortex Tubes
  • E-Vac Vacuum Generators
  • Cabinet Cooler Systems
  • Remote exhaust routing

Because the airflow passes directly through the muffler body, Straight-Through Mufflers are also less susceptible to clogging in certain applications.

Selecting the Right Muffler

Each EXAIR muffler style is designed to solve a different challenge:

Muffler TypePrimary BenefitTypical Use
Reclassifying MufflersBest noise reduction and oil removalPneumatic cylinders and lubricated systems
Sintered Bronze MufflersLow cost and easy installationGeneral pneumatic exhaust applications
Straight-Through MufflersRemote exhaust routing and lower clogging riskVacuum generators, vortex tubes, cabinet coolers

Reducing compressed air exhaust noise is often a simple upgrade that can have a major impact on workplace safety and operator comfort. Whether the goal is maximum sound reduction, oil mist filtration, or economical silencing, EXAIR offers a muffler solution designed for the application.

Jordan Shouse
Application Engineer
E: JordanShouse@exair.com
O: (513) 671‑3322
F: (513) 671‑3363
A: 11510 Goldcoast Dr Cincinnati OH 45249
www.exair.com

Find time on my calendar by scheduling a meeting here.

Measuring and Adding Sounds

Published on by John BallLeave a comment

My colleague, Russ Bowman, wrote a blog about “Sound Power vs Sound Pressure vs Sound Pressure Level”.  He discussed the logarithmic equations around sound.  I will be discussing what happens when you have more than one sound source, as often heard within manufacturing plants.  Sounds can be added together to determine the overall sound level that you hear.  This is very important when it comes to minimizing hearing loss.

In looking at a single source of sound, sound pressure is created by the loudness of a noise.  The units are measured in Pascals.  The lowest pressure perceived by human hearing is 0.00002 Pa, and we can use this value as a reference point.  From sound pressures, we can arrive at a sound pressure level which is measured in decibel, dB.  This correlation between sound pressures and sound pressure levels are calculated by Equation 1:

L = 20 * Log10 (P / Pref)

L – Sound Pressure Level, dB

P – Sound pressure, Pa

Pref – reference sound pressure, 0.00002 Pa

As an example, the sound pressure from a passenger car as heard from the roadside is 0.1 Pa.  With Equation 1, we can get the following decibel level:

L = 20 * Log10 (0.1Pa/0.00002Pa) = 74 dB

Because human ears are sensitive to different frequencies, the sound pressure levels can be modified, or weighted, to indicate an effective loudness level for humans.  This adjustment is done in two different ways; A-weighting and C-weighting.  The C-weighting is for very loud noises with high peaks or sharp impacts like gunfire. The A-weighting is the most used value as the sound pressure levels are adjusted by the frequency level.  For higher and lower frequencies, the change in the sound value is much greater than the mid-level frequencies that are within our hearing range.  Sound measurements for safety are measured on an A-weighted scale.  OSHA created a chart in the standard 29CFR-1910.95(a).  It shows the noise levels over exposure times for an operator.  To use the OSHA chart accurately, the total noise level in dBA should be calculated.

Hearing loss is the best known, but not the only, ill effect of harmful noise exposure. It can also cause physical and psychological stress, impair concentration, and contribute to workplace accidents or injuries.

To determine the total sound level, we can add all the sound pressure levels together by Equation 2:

Equation 2:

Where L1, L2… represents the sound pressure level in dBA for each sound source.

As an example, a manufacturing plant had an operator using a machine that had four copper tubes to blow off a cutting operation (reference photo below).

Blow off station

The decibel level for a copper tube was measured at 98 dBA.  The total amount of sound that the operator was exposed to was determined by Equation 2 with four values.

L = 10 * log10 (109.8 + 109.8 + 109.8 + 109.8)

L = 104 dBA

In looking at the OSHA chart above, the operator would only be allowed to operate the machine only a little over one hour without hearing protection.  In this same example, we replaced the copper tubes with an EXAIR Super Air Nozzle, model 1100SS.  The noise level for each nozzle is 74 dBA at 80 PSIG (5.5 bar).  By replacing all four copper tubes with Super Air Nozzles, Equation 2 becomes:

L = 10 * log10 (107.4 + 107.4+ 107.4 + 107.4)

L = 80 dBA

The total sound level is now in accordance with OSHA regulations for the operator to work all 8 hours at the machine without hearing protection.

A commonly used acronym for hearing safety is NIHL, or Noise Induced Hearing Loss.  To keep your operators safe and reduce NIHL, it is important to measure the total sound level in that area.  As a protocol in safety, it is a requirement to use engineering standards before purchasing personal protective equipment or PPE.  For the customer above, they followed that protocol with our Super Air Nozzles.  If you need to reduce noise levels in your facility, EXAIR offers a large line of blow-off products that can meet the safety requirements.  You can contact an Application Engineer for more information. 

John Ball
Application Engineer
Email: johnball@exair.com
Twitter: @EXAIR_jb

Photo: Ear by PublicDomainPictures  Pixabay License

Sound Level of Cicadas

Published on by Jordan T ShouseLeave a comment

At the time of writing this blog, Cincinnati is experiencing our usual 17-year brood of cicadas. Millions, if not billions, of 17-year cicadas have emerged in Cincinnati and Southwest Ohio, making spending any amount of time outside unbearable. My four-year-old’s favorite part of the day is swinging on the back porch, and he even wants to go right back inside after just a few minutes.

I stuck the EXAIR 9104 Digital Sound Level Meter inside of one of our bushes here at the office. Within a 3′ radius, I counted 10–15 cicadas crawling around pretty casually. And they were producing a whopping 90 dBA! And if i shook a branch and really got them worked up, it peeked over 101 dBA.

Now while it takes repeated exposures of sufficient duration to cause hearing loss. And in a few weeks these cicadas will be gone; you probably don’t need to worry about the 2025 cicadas affecting your hearing. Noise exposure is, however, a real issue for most manufacturing facilities. Due to this risk, OSHA strictly enforces standard 29 CFR-1910.95(a).

This directive outlines the effects of noise and limits exposure based on the dBA. The table below indicates the maximum allowable exposure time to different noise levels. Sound levels that exceed these levels should first be addressed by proper engineering controls, such as isolating the source of the sound from personnel or replacing the cause of the sound with something like an engineered compressed air nozzle. When such controls aren’t feasible, proper PPE must be worn to protect the operator.

Hearing loss is the best known, but not the only, ill effect of harmful noise exposure. It can also cause physical and psychological stress, impair concentration, and contribute to workplace accidents or injuries.

Hearing loss can occur in as little as 30 minutes when exposed to sound levels of 110 dBA or greater. Operators have a tendency not to use PPE as directed. If an OSHA inspector comes to your facility and notices that the sound levels exceed the maximum allowable level without PPE protection being worn, hefty fines will soon be following. In this example from the United States Department of Labor, a company was fined a total of $143,000 for failing to protect their employees.

EXAIR 9104 Sound Level Meter

In order to identify the places or processes in your facility that are causing the problems, you’ll need a tool to measure the sound level. EXAIR’s easy-to-use Digital Sound Level Meter allows you to measure and monitor the sound level pressure in a wide variety of industrial environments. The source of the loud noise can then be identified and isolated so that corrective action can be taken. For compressed air-related noise, EXAIR manufactures a wide variety of engineered compressed air products that can reduce the sound level dramatically. In many cases, EXAIR products are capable of reducing noise levels by as much as 10 dBA. Since the dBA scale is logarithmic, this equates to cutting the sound level in half!

If there are processes within your facility that are above these limits, and you’d like to eliminate relying on proper PPE, give an Application Engineer a call. We’ll help walk you through the selection process and make sure that when the OSHA inspector comes knocking you’re prepared! Sorry, but we will not be able to help you with your Cicada problems. We just have to let nature do its thing, and they will be gone in a few weeks. Until 2027, that is, when we get hit with the 10-year brood!

Jordan Shouse, CCASS

Application Engineer

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Industrial Safety: Compressed Air

Published on by John BallLeave a comment

At EXAIR, we have a statement that says, “Safety is everyone’s responsibility.”  EXAIR builds its name around manufacturing safe and protective compressed air products.  In the United States, we have an organization called the Occupational Safety and Health Administration (OSHA) that enforces governmental directives for safe and healthy working environments.  They do training, outreach programs, and educational assistance for manufacturing plants to reduce injuries and fatalities.  They can also enforce these directives with heavy fines for violations.  With compressed air systems, the two most common violations are 29CFR 1910.242(b) for dead-end pressure/chip shielding and 29CFR 1910.95(a) for maximum allowable noise exposure.

Unsafe Nozzle

Here is an example of a nozzle that is dangerous.  As you can see, there is only one path where the air can pass through.  Other similar types of blow-off devices that would fall into this same group would include copper tubes, flexible lines, and open pipes.  They are dangerous as compressed air cannot escape if it is blocked by your body or skin.  If operated above 30 PSIG (2 bar), these nozzles could penetrate the skin and create an air embolism within the body, which can cause bodily harm or death.  This is a hazard that can be avoided by using EXAIR Super Air Nozzles and Safety Air Guns.  The nozzles are designed with fins, which allow the air to escape and cannot be blocked by your skin.  So, you can use the EXAIR Super Air Nozzles safely above 30 PSIG (2 bar) and remain OSHA compliant.

Unsafe Air Gun

To counteract the dead-end pressure violation, some nozzle manufacturers create a hole through the side of the nozzle (reference photo above).  This will allow the compressed air to escape, but now the issue is noise levels.  With an “open” hole in the nozzle, the compressed air is very turbulent and very loud.  The National Institute for Occupational Safety and Health (NIOSH) states that 70% to 80% of all hearing loss within a manufacturing plant is caused by compressed air.  OSHA created a chart to show the maximum allowable noise exposure.  This chart shows the exposure time and noise limits before hearing protection is required.  The EXAIR Super Air Nozzles, Super Air Knives, and Super Air Amplifiers are designed to have laminar flow, which makes them very quiet.  As an example, the model 1210 Soft Grip Safety Air Gun has a sound level of only 74 dBA, well under the noise exposure limit for 8 hours.

One of the last things that companies think about when purchasing compressed air products is safety.  Loud noises and dead-end pressure can be missed or forgotten.  To avoid any future fines or having to purchase additional personal protective equipment (PPE), it will be much safer to purchase EXAIR products.  If you would like to improve the safety of your facility and reduce energy costs, an Application Engineer at EXAIR can review your current blow-off devices.  Remember, safety is everyone’s responsibility. 

John Ball
Application Engineer
Email: johnball@exair.com
Twitter: @EXAIR_jb

Photo: Industrial Security Signal by DavidRockDesign.  Pixabay license