EXAIR Digital Sound Level Meters Measure Noise Exposure Levels

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Digital Sound Meter

EXAIR offers the model 9104 Digital Sound Level Meter.  It is an easy to use instrument for measuring and monitoring the sound level pressures in and around equipment and other manufacturing processes.

Sound meters convert the movement of a thin membrane due to the pressure waves of sound into an electric signal that is processed and turned into a readable output, typically in dBA.  The dBA scale is the weighted scale that most closely matches the human ear in terms of the sounds and frequencies that can be detected.

Noise induced hearing loss can be a significant problem for many workers in manufacturing and mining. To protect workers in the workplace from suffering hearing loss OSHA has set limits to the time of exposure based on the sound level.  The information in the OSHA Standard 29 CFR – 1910.95(a) is summarized below.

OSHA Noise Level

The EXAIR Digital Sound Level Meter is an accurate and responsive instrument that measures the decibel level of the sound and displays the result on the large optionally back-lit LCD display. There is an “F/S” option to provide measurement in either ‘slow’ or ‘fast’ modes for stable or quickly varying noises. The ‘Max Hold’ function will capture and hold the maximum sound level, and update if a louder sound occurs.

Certification of accuracy and calibration traceable to NIST (National Institute of Standards and Technology) is included.

If you have questions about the Digital Sound Level Meter, or would like to talk about any of the quiet EXAIR Intelligent Compressed Air® Products, feel free to contact EXAIR and myself or one of our Application Engineers can help you determine the best solution.

Jordan Shouse
Application Engineer
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Measuring and Adding Sound Levels

Noise-induced hearing loss, or NIHL, is one of the most common occupational diseases. This doesn’t occur overnight, but the effects are noticed gradually over many years of unprotected exposure to high sound levels. This is 100% preventable! Through proper engineering controls and personal protective equipment (PPE), NIHL can be prevented. It is irreversible, so once the damage is done there’s no going back. OSHA standard 19 CFR 1910.95(a) states that protection against the effects of noise exposure shall be provided when the sound levels and exposure time exceed those shown in the table below.

OSHA Chart

Intensity of the sound pressure level is expressed in decibels (dB). The scale is logarithmic, a 3 dB reduction cuts the sound level in half. A 10 dB reduction decreases it by a factor of 10, and a 20 dB reduction decreases the sound level by a factor of 100. To calculate the dB level, we use the following formula:

Sound SPL

Where:

L – Sound Pressure Level, dB

P – Sound Pressure, Pa

Pref – reference sound pressure, 0.00002 Pa

For example, normal conversation has a Sound Pressure of .01Pa. To calculate the dB level:

dB = 20 log10 (.01Pa/.00002Pa)

 = 54 dB

When designing a new blowoff process, it’s important to consider the sound levels produced before implementation. EXAIR publishes the sound level for all of our products for this very reason. If you’re implementing multiple nozzles, you’ll need to add the sound levels together. To do so, we use the following formula:

Sound Addition

Where:

L1, L2… represent the sound pressure level in dB for each source

A customer was using ¼” open ended copper tubes for a blowoff application removing trim after a stamping operation. They had a total of (4) tubes operating at 80 PSIG. Not only were they VERY inefficient, but the sound level produced at this pressure was 94 dBA. To calculate the sound level of all (4) together we use the above formula:

L = 10 x log10(109.4+ 109.4 + 109.4 + 109.4)

L = 100 dB

At this sound level, permanent hearing loss begins to occur in just two hours of unprotected exposure. We recommended replacing the loud and inefficient copper pipe with our 1” Flat Super Air Nozzle, Model 1126. At 80 PSIG, the 1126 produces a sound level of just 75 dBA.

L = 10 x log10 (107.5 + 107.5 + 107.5 + 107.5)

L = 81 dB

At almost a 20 dB reduction, that’s nearly 100x quieter! Don’t rely on just PPE to keep your operators safe from NIHL. Replacing loud inefficient blowoff methods with EXAIR’s Intelligent Compressed Air Products will take it one step further in ensuring your creating a safe working environment for your employees.

Tyler Daniel
Application Engineer
E-mail: TylerDaniel@EXAIR.com
Twitter: @EXAIR_TD

EXAIR Nano Super Air Nozzles for Science and Industry!

A few weeks ago I was on vacation with my family. My wife and I had taken our three daughters to Columbus, OH for three days after camping in a tent for a few days. One of the focal points to the trip was COSI, the Center of Science and Industry. In case you live anywhere near Columbus, OH and have not heard of how amazing this interactive museum is, you should definitely check it out. This isn’t your normal museum.

While the Mythic Creatures exhibit and the Jim Henson exhibit were both absolutely amazing for my 9, 6 and 4 year old daughters, it was also entertaining for my wife and myself. Now you may be asking what does this interactive science place and trip with kids have to do with EXAIR.

Well, while my daughters and I were watching this enormous pendulum that knocks ball bearings off boxes every few minutes I could hear that all too familiar, gentle sound of compressed air blowing every now and then. I couldn’t however see where the noise was coming from.

COSI Pendulum

As we wandered through the different sections I saw several examples of compressed air use but none were the exact sound or display I had heard. When we were walking through the Space exhibit just above where the pendulum was located and that gentle sound was getting closer. All of a sudden I saw it. Next thing I know I look up and my 6 year old was using a joystick to control a scaled down Lunar Lander propelling it in circles. This was where the sound was coming from.

Propelled Lunar Lander

While I was amazed by this interactive piece I could tell they were using compressed air and I was curious as to how it was working. That’s when I noticed the distinct design of our Nano Super Air Nozzle on the bottom of the Lander. Here’s a close up picture, well as close as the handrail would allow me to get without over reaching.

EXAIR Model 1110SS-NPT – Nano Super Air Nozzles

The interesting part to this is how this setup gives an idea of the amount of thrust given off by a nozzle that only consumes 8.3 SCFM of compressed air when powered at 80 psig inlet pressure. These nozzles can easily be fitted to blast debris or moisture out of small pockets or hard to reach areas. They also can be used to help direct product that may be getting diverted to a new conveyor. And, obviously, they can be used to propel scale models of lunar landers. 

If you would like to discuss any application for point of use compressed air, and I do mean ANY, give us a call. If I can’t help with the application we will at the very least do our best to send you in the right direction.

Brian Farno
Application Engineer
BrianFarno@EXAIR.com
@EXAIR_BF

Limiting Noise Exposure with Mufflers for Compressed Air

Mufflers come in many shapes and sizes. Each with their own benefits.

If you have ever walked into a manufacturing facility and heard the hiss or even worse the banshee scream of compressed air being exhausted to ambient, whether it be from a cylinder discharge, a timed drain going off, or a bypass valve being activated, they all could be hushed with a muffler. A muffler for compressed air comes in several shapes and sizes. EXAIR offers four separate types from stock to help attenuate the noise disruption within your facility.

The OSHA standard for allowable noise exposure is 29 CFR-1910.95(a) and outlines the number of hours per day any individual can be exposed to a particular noise level. These noise levels are expressed in decibels (dbA).

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.
Reclassifying Mufflers attenuating the exhaust of a pneumatic cylinder.

The first type I would like to showcase are the Reclassifying Mufflers. These are ideal for cylinder exhausts or valves which commonly contain an oil mist within the air stream which can easily contaminate the surrounding area. The patented design of the removable element separates oil from the exhausted air so virtually no atomized oil is released into the environment. They also attenuate the exhaust noise level up to 35 decibels. The filter element helps the exhaust to meet the OSHA Standard 29 CFR 1910.1000, a worker’s cumulative exposure to oil mist must not exceed 5 mg/m³ by volume in any eight hour shift of a forty hour work week.

The chart below helps to properly size the Reclassifying Muffler for a pneumatic cylinder. One key to proper installation of these mufflers is they must be installed vertically in order to properly trap and drain the oil.

Reclassifying Muffler Quick Pick Chart
Sintered Bronze mufflers are excellent choices for tight installation locations and are easily sized.

The next type of muffler to discuss are the Sintered Bronze Mufflers that are offered in ten different sizes. These are an excellent low cost solution which easily install into new or existing ports. Each size is designed to provide minimal back pressure and restriction for the individual port size. The quick pick chart below helps to easily select the correct size for attenuating the exhaust of a pneumatic cylinder. One key difference between these and the Reclassifying Mufflers is, these do not have to be oriented vertically as they do not collect the oil out of the exhaust air.

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The model 3913 – 3/4″ NPT Straight Through Muffler

If the process air needs to be directed or plumbed away from the operator then the Straight Through Mufflers are the ideal selection as they offer an NPT threaded inlet and exhaust. They are available in three standard NPT sizes from stock. These mufflers can be installed in any orientation and work well with our Vortex Tubes to help pass the cold air through while lowering the operating sound level of the tube. The average noise reduction of the Straight-Through Mufflers is 20 dB. This can easily reduce the noise level of an operation to below the OSHA standard requiring hearing protection for operators in the area.

The model 3903 Heavy Duty Muffler

The final option for mufflers from EXAIR are the Heavy Duty Mufflers. These are available in two sizes from stock and are constructed of corrosion-resistant aluminum with a stainless steel internal screen. These can be installed in any orientation and are ideal for protecting exhaust ports from contaminants that may clog or damage the device they are attached to. The typical noise reduction from installation is 14 dB with these mufflers.

These are available in two sizes from stock and are constructed of corrosion-resistant aluminum with a stainless steel internal screen. These can be installed in any orientation and are ideal for protecting exhaust ports from contaminants that may clog or damage the device they are attached to. The typical noise reduction from installation is 14 dB with these mufflers.

To summarize, EXAIR offers a multitude of options when it comes to lowering sound levels in operation areas that are caused by exhausted compressed air. Each of the mufflers discussed above are shipped same day from stock to meet your immediate need. If you are unsure of which muffler to use for your application, feel free to contact an Application Engineer.

Brian Farno
Application Engineer
Ph. 1-513-671-3322
BrianFarno@EXAIR.com
@EXAIR_BF

Brian Farno
Application Engineer
BrianFarno@EXAIR.com
@EXAIR_BF