Mufflers to Protect Manufacturing Workers Hearing

Mufflers

Many manufacturing plants have a strong focus on safety for their workers.  One major safety concern that is overlooked is noise.   OSHA, Occupational Safety and Health Administration, has a directive that defines the noise exposure over time; 29CFR 1910.95(a).   For an eight-hour day, the maximum noise level is 90 dBA.  Hearing loss is irreversible, but it can be preventable.  The CDC, Center for Disease Control, and NIOSH, National Institute for Occupational Safety and Health, report that “approximately 18% of all manufacturing workers have hearing difficulty”1

EXAIR manufactures engineered products to reduce noise levels in the work environment.  We offer Super Air Nozzles and Safety Air Guns for blow-off applications and pneumatic mufflers for discharge exhaust.  In this blog, I will cover the different types of EXAIR Mufflers that we offer.   

  1. Reclassifying Mufflers are designed to have two functions. They can cut noise levels by 35 dB and remove oil mist from the exhaust air.  Cylinders and valves that exhaust pressurized air may have oil in the line to keep the seals from sticking.  When exhausted, it can create a fine mist which is dangerous for operators.  The Reclassifying Mufflers can reduce the loud noise as well as collect any contamination from the exhaust air.
  2. Sintered Bronze Mufflers are simple in design, cost effective, and easy to install. They have a minimal back pressure to not restrict operations of the pneumatic device.  They come in sizes from #10-32 thread to 1-1/2” NPT.  For a quick and simple way to reduce noise, the Sintered Bronze Mufflers are in stock for fast delivery.
  3. Straight-Through Mufflers offer a way to reduce noise levels without worrying about clogging. They have an aluminum shell lined with sound absorbing foam, and they can reduce the noise level by 20 dB.  EXAIR offers them with ports of ¼” NPT, 3/8” NPT, and ¾” NPT.  One side has a female thread while the opposite side will have a male thread.  This can allow you to connect other items like hose kits to reduce noise.
  4. Heavy Duty Mufflers are used within aggressive environments.  They have an outer aluminum shell with an internal stainless-steel screen.  They protect components like valves and cylinders from contamination entering into the part.  And, the Heavy Duty Muffler can keep contaminant like rust from being ejected at high speed into the work area. They have a typical noise reduction of 14 dB.

Here is a test for you.  If you go and stand in your plant, you can probably hear loud noises coming from your compressed air system.  EXAIR has an engineered product to solve most of them.  On the Hierarchy of Controls for NIOSH, Personal Protection Equipment, PPE, is the least effective.  A better control would be to isolate your operators from the hazard with an engineered product.  EXAIR can offer that solution for many of your blow-offs and pneumatic discharges to reduce noise levels.  This would include; and not limited to; Super Air Nozzles, Safety Air Guns, Super Air Knives, and Mufflers.  If you wish to discuss further the safety improvements that EXAIR can provide, you can contact an Application Engineer.  We will be happy to help. 

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

Note 1: https://www.cdc.gov/niosh/topics/ohl/manufacturing.html

EXAIR Product Overview: Mufflers

Noise, we all hate it to some extent. From the hustle and bustle of crowed streets to the whine of a jet engine noise has plagued the world for eons leaving people to search for a way to escape into a moment of peace and quiet. The majority of people that I know pack their massive over sized backpacks and head deep into the mountains for days on end to escape the noise sometimes traveling for 10+ miles at a time. But how can we help eliminate this monstrosity that we have created in our manufacturing environments? The answer is mufflers, and no I don’t mean your car muffler (although they do the same thing) I mean compressed air mufflers. Compressed air can be a loud utility inside of a plant environment and exceed the OSHA guidelines for personnel noise exposure. But this noise can easily be mitigated with the use of Intelligent compressed air products and mufflers.

Big Sandy Lake Trail – Wind River Range State Park, WY

OSHA Standard 29 CFR 1910.95(a) outlines the total noise exposure to a particular noise level per day and dictates that noise exposure at or above 85 decibels require ear protection. By placing a muffler on the end of the pipe one can reduce the sound level significantly to the point it could be the difference between having to wear ear protection and not having to. With that being said EXAIR offers four different types of mufflers to choose from and they are Reclassifying, Sintered Bronze, Straight-Through, and Heavy Duty.

Reclassifying mufflers offer the best noise reduction at 35 dB and have the added benefit of removing oil mist from the air line. This means that the Reclassifying mufflers are ideal for pneumatic cylinders. Per OSHA Standard 29 CFR 1910.1000 worker shall not be exposed to more than 5mg/m3 of oil by volume in a 40-hour work week. The patented design of the removable element separates oil from the exhausted air and meets or exceeds the OSHA Standard.

Sintered Bronze Mufflers are an excellent low-cost solution which can be easily installed into your current existing ports. These mufflers also come in the largest variety of different sizes ranging from thread sizes of #10-32 to 1.5” NPT. Also, the Sintered Bronze Mufflers are specifically designed to provide the minimal amount of back pressure and restriction. The main difference between these mufflers and the reclassifying is that the Sintered Bronze Mufflers cannot collect oil out of the exhaust.

The quick pick chart for easily choosing which muffler you need

If the process air needs to be directly plumbed away from personnel, then the Straight-Through Muffler is the way to go. Straight-Through Mufflers are ideal for situations that require both a threaded inlet and exhaust. In most applications you will see the Straight-Through Muffler pair with our E-Vac vacuum generators or Vortex Tubes to provide noise reduction of the unit. All in all, the Straight-Through Muffler can reduce noise levels up to 20 dB.

Model 3913 Straight-Through Muffler

Lastly, the Heavy Duty Muffler provides a corrosion resistant aluminum outer shell with a stainless steel inner screen. This design allows the muffler to catch any contaminants such as rust from being ejected potentially causing harm or quality defects. Typically, this muffle will reduce noise levels up to 14 dB.

Model 3903 Heavy Duty Muffler

If you have any questions or want more information on EXAIR’s E-Vacs and their Accessories. Give us a call, we have a team of application engineers ready to answer your questions and recommend a solution for your applications.

Cody Biehle
Application Engineer
EXAIR Corporation
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Benefits of Engineered Air Jets and Nozzles

EXAIR’s Engineered Air Nozzles and Air Jets provide a superior solution to minimize compressed air usage and reduce noise levels for compressed air blow-off operations.

Air Nozzles and Jets – when compared to commonly used open copper tubes or pipes the compressed air savings can be as high as 80%. With less compressed air, sound levels are greatly reduced.  A 10 dBA noise level reduction is typical.  All EXAIR Air Nozzles and Jets meet OSHA guidelines for dead end pressure and sound level exposure standards.
EXAIR Air Jets

EXAIR Nozzles and Jets are designed and manufactured to take advantage of the Coanda (wall attachment of a high velocity fluid) effect which can amplify the airflow up to 25 times. The compressed air exits through the small holes on the nozzle which entrains the surrounding air. The effect from this is a high volume, high velocity blast using less compressed air.  EXAIR manufactures many sizes and styles of air nozzles from the smallest, but quite powerful M4 x 0.5 thread Atto Super Air Nozzles to our largest 1-1/4 NPT Super Air Nozzle.  We also offer Flat Super Air Nozzles, and the Back Blow style nozzle for cleaning out tubes, pipes, channels or holes from 1/4″ to 16″ in diameter.

The Air Jets are 1/8 NPT threads and blow air out at a right angle from the inlet. They produce a vacuum on the larger diameter side which pulls in surrounding ambient air into the total output flow. Air Jets are available in brass or Type 303 stainless steel. You can choose from a fixed flow style or an adjustable flow style to provide flexibility for your applications. The adjustable flow models have a clear micrometer air gap indicator to assure consistent and accurate results.

All of our Air Nozzles and Jets  are engineered to meet or exceed OSHA Standard 1910.24(b) for 30 PSIG dead end pressure, they cannot be dead-ended as there is always a route for the air to escape. In addition, our products are going to meet the OSHA Standard CFR 29 – 1910.95(a) for allowable noise exposure levels.

EXAIR’s Flat Super Air Nozzles have been blowing away the competition since 2003.

EXAIR’s Swivel Fittings make it easy to adjust the position of the Air Nozzles and Air Jets.  The fittings allow for movement of 25° form the center axis for a total movement of 50°.  There are nine different models available and all of them are made from stainless steel

EXAIR Swivel fittings

If you would like to discuss blow off, noise levels, dead end pressure or any of EXAIR’s Intelligent Compressed Air® usage solutions, I would enjoy hearing from you…give me a call.

Jordan Shouse
Application Engineer

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Two Important Safety Factors When Choosing Air Nozzles

At EXAIR, we have a statement, “Safety is everyone’s responsibility”.  And we also manufacture safe compressed air products.  In the United States, we have an organization called Occupational Safety and Health Administration, OSHA, that enforces directives for safe and healthy working environments.  They do training, outreach programs, and educational assistance for manufacturing plants.  They will also enforce these directives with heavy fines for violations.  The two most common violations with compressed air are air guns and blow-off devices are described in 29CFR 1910.242(b) for dead-end pressure/chip shielding and 29CFR 1910.65(a) for maximum allowable noise exposure.

Here is an example of a nozzle that is dangerous.  As you can see, there is only one opening where the air can come out from the nozzle.  Other types of nozzles that would fall into this same group would include copper tube, extensions, and open pipes.

Unsafe Nozzle

They are dangerous as the compressed air cannot escape if it is blocked with your body or skin.  If operated above 30 PSIG (2 bar), these nozzles could create an air embolism within the body which can cause bodily harm or death.  This is a hazard which can be avoided by using EXAIR Super Air Nozzles and Safety Air Guns.  The nozzles are designed with fins which allows the air to escape and not be blocked by your skin.  So, you can use the EXAIR Super Air Nozzles safely even above 30 PSIG (2 bar).

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 for the compressed air to escape, but, now the issue is noise level.  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 time and noise limits before requiring hearing protection.  The EXAIR Super Air Nozzles, Super Air Knives, Super Air Amplifiers are designed to have laminar flow which is very quiet.  As an example, the model 1210 Safety Air Gun has a sound level of only 74 dBA; well under the noise exposure limit for 8 hours.

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.

NIOSH created an overview of how to handle hazards in the workplace.  They call it the Hierarchy of Controls to best protect workers from dangers.  The most effective way is by eliminating the hazard or substituting the hazard.  The least effective way is with Personal Protective Equipment, or PPE.  For unsafe compressed air nozzles and guns, the proper way to reduce this hazard is to substitute it with an engineered solution.

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 stop any future fines or additional personal protective equipment (PPE), it will be much cheaper to purchase an EXAIR product.  And with the Hazard Hierarchy of Controls, the first method is to remove any hazards.  The last method for control is to use PPE.  In the middle of the hierarchy is for an engineered solution.  EXAIR products are that engineered solution.  If you would like to improve the safety in your facility with your current blow-off devices, an Application Engineer can help you.

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

Picture:  Safety First by SuccoPixabay License