Minimize Exposure to Hazards Using the Hierarchy of Controls

The CDC (Center for Disease Control) published a useful guide called “Hierarchy of Controls” that details (5) different types of control methods for exposure to occupational hazards while showing the relative effectiveness of each method.

CDC Hierarchy of Controls

The least effective methods are Administrative Controls and PPE. Administrative Controls involve making changes to the way people perform the work and promoting safe practices through training. The training could be related to correct operating procedures, keeping the workplace clean, emergency response to incidents, and personal hygiene practices, such as proper hand washing after handling hazardous materials. PPE (Personal Protective Equipment) is the least effective method because the equipment (ear plugs, gloves, respirators, etc.) can become damaged, may be uncomfortable and not used, or used incorrectly.

In the middle range of effectiveness is Engineering Controls. These controls are implemented by design changes to the equipment or process to reduce or eliminate the hazard. Good engineering controls can be very effective in protecting people regardless of the the actions and behaviors of the workers. While higher in initial cost than Administrative controls or PPE, typically operating costs are lower, and a cost saving may be realized in the long run.

The final two, Elimination and Substitution are the most effective but can be the most difficult to integrate into an existing process. If the process is still in the design phase, it may be easier and less expensive to eliminate or substitute the hazard. Elimination of the hazard would be the ultimate and most effective method, either by removing the hazard altogether, or changing the work process to the hazardous task is no longer performed.

EXAIR can help your company follow the Hierarchy of Controls, and eliminate, or reduce the hazards of compressed air usage.

Engineers can eliminate loud and unsafe pressure nozzles with designs that utilize quiet and pressure safe engineered air products such as Air Nozzles, Air Knives and Air Amplifiers. Also, unsafe existing products such as air guns, can be substituted with EXAIR engineered solutions that meet the OSHA standards 29 CFR 1910.242(b) and 29 CFR 1910.95(a).


In summary, Elimination and Substitution are the most effective methods and should be used whenever possible to reduce or eliminate the hazard and keep people safe in the workplace.

If you have questions about the Hierarchy of Controls and safe compressed air usage from any of the 15 different EXAIR Intelligent Compressed Air® Product lines, feel free to contact EXAIR and myself or any of our Application Engineers can help you determine the best solution.

Brian Bergmann
Application Engineer
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Reduce Sound Level with EXAIR’s Flat Super Air Nozzles

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

The patented design of EXAIR’s 1” and 2” Flat Super Air Nozzles make them a highly efficient option when seeking a powerful, flat airflow. A precise air gap across the width of the nozzle provides a forceful stream of high velocity, laminar airflow without consuming high amounts of compressed air and also resulting in a greatly reduced sound level compared to some of the alternative flat nozzles available in the market.

EXAIR’s Flat Super Air Nozzles are safe, reliable, and efficient. Here on the EXAIR Blog we frequently discuss dead-end pressure as explained in OSHA Standard 1910.242(b). This directive states that the when compressed air is used for cleaning purposes, the dead-ended pressure must not exceed 30 psig. When pressures greater than this occur, there is potential for an air embolism.

EXAIR’s Flat Super Air Nozzles cannot be dead-ended, which allows us to operate at pressures well above the 30 psig limit. Some competition markets their nozzles as “Extremely Quiet”, but a deeper look into their performance specifications shows that the published sound level reading was taken at a pressure of 29 psig. They must use a pressure of 29 psig because the nozzles are not OSHA compliant at pressures exceeding 30 psig. For the same competitive nozzle, there is no path for air to escape if the nozzle were to be dead-ended or pressed up against the skin. At 29 psig, the nozzle simply isn’t very effective as it doesn’t provide enough force for most applications. This very same nozzle, when operated at 80 psig, actually has a sound level of 85 dBA.


EXAIR’s Model 1122 delivers more force, more efficiently, and at a sound level of just 77 dBA at 80 psig. Remember, sound levels are expressed in dBA as a logarithmic function. This represents a decrease in sound level by 60%! If you’re looking for a means of reducing sound level in your plant, EXAIR’s 1” and 2” Flat Super Air Nozzles are just what you need.

In addition to being very quiet EXAIR’s flat super air nozzles integrate a shim used to adjust the air gap, which changes the maximum airflow and force. Thicker shims will produce more force and flow, while a thinner shim would do just the opposite.Some applications require more force and some require less, which is not always achieved through simple pressure adjustments so the shims provide the flexibility needed for success.

They’re on the shelf in stock. With same day shipping on orders placed by 3:00 ET and an Unconditional 30-Day Guarantee, there’s no excuse to not give them a try!

Tyler Daniel
Application Engineer
Twitter: @EXAIR_TD

What is Sound and Interesting Facts About Sound

In physics, sound is a wave of pressure. It occurs in a medium, which can be a solid, liquid or gas. Sound cannot travel through a vacuum, such as in space. The wave of pressure reaches our ears and causes the ear drum to vibrate, which then goes through a complex process to ultimately be perceived as audible sound.

There are several characteristics of sound waves that can be measured and help define the sound. A sound wave can be visualized as a repeating sinusoidal wave (see below), and can be described by these properties – frequency and wavelength, amplitude, and speed.

Sound Wave
Sound Wave
  • Frequency is the number of cycles in 1 second, and is measured in Hertz (Hz)
  • Wavelength is the distance over which 1 cycle occurs, and for audible sound is  between 17 m and 17 mm long
  • Amplitude is the measure of its change over a single period, and normally a measure of sound loudness
  • Speed is the distance traveled per unit time

The speed of sound in air can be found using the equation:  a = Sqrt (γ•R•T)

where for air:
γ = ratio of specific heats = 1.4,
R = gas constant = 286 m²/s²/K
T = absolute temperature in °K (273.15 + °C)

At room temperature, 22°C (71.6°F), the speed of sound is 343.8 m/s (760 mph)

Some interesting facts about sound:

  • Sounds generally travels faster in solids and liquids than in gases.
  • You can estimate the distance from a lightning strike by counting the seconds that pass between seeing the lightning flash and hearing the thunder.  Take this duration an divide by 5 to get the distance away, in miles.
  • Humans normally hear sound frequencies between 20 Hz and 20,000 Hz.
  • Sound waves above 20,000 Hz are known as ultrasound, and sound waves below 20 Hz are known as infrasound.
  • Sound travel through water close to 4 times faster then through air.
  • The sound of a cracking whip occurs because the speed of the tip has exceeded the speed of sound.

Sound that is too loud can be a problem. The Occupational Safety and Health Administration (OSHA) has set limits on the noise exposure that an employee can be subjected. Exceeding these values can cause permanent damage to your ears and cause noise induced hearing loss. So, knowing and reducing the sound levels within a manufacturing operation is important.

OSHA Chart

EXAIR has many products that can help reduce the sound levels in your processes.  With products such Air Knives, Air Wipes, Air Amplifiers, Air Nozzles and Jets, and Safety Air Guns, strong, quiet and efficient blowoff, drying, and cooling can be performed.

Quiet Products

If you have questions about sound and keeping your sound levels in check or any of the 15 different EXAIR Intelligent Compressed Air® Product lines, feel free to contact EXAIR and myself or any of our Application Engineers can help you determine the best solution.

Brian Bergmann
Application Engineer
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Understanding Decibels & Why OSHA Pays Attention to Your Noise Exposure

In the simplest of metric terms, a decibel is one-tenth of a bel.  But, historically, bel was a unit created to honor Alexander Graham Bell who invented the telephone.  In the early days with telephone wires, they noticed that the signal strength would decay over a long distance.  In order to determine power requirements to connect people for communications, they determined that they could use the ratio of power levels.  As a start, it had to be based on a minimum amount of power required for a person to hear on the telephone.  They found that the signal power level to generate an angular frequency of 5000 radians per second would be that minimum value as determined by an average number of people.  They used this mark as a reference point in the ratio of power levels.  Because of the large variations in values, they simplified the equation on a base-10 log scale and dividing the bel unit by 10.  Thus, creating the measurement of decibel.

Today, this same method is used to measure sound.  Like frequency waves that travel through the telephone wires, pressure waves travel through the air as sound.  This sound pressure is what our ears can detect as loudness, and it has a pressure unit of Pascals (Pa).  As an example, a small sound pressure would be like a whisper while a large sound pressure would be like a jet engine.  This is very important to know as high sound pressures, or loudness, can permanently damage our ears.

With sound pressures, we can determine the Sound Pressure Level (SPL) which is measured in decibels (dB).  Similar to the equation for the telephone power signals above, the SPL also uses a ratio of sound pressures in a base-10 logarithmic scale.  For a minimum reference point, an average human can just start to hear a sound pressure at 0.00002 Pa.  So, the equation for measuring sound levels will use this minimum reference point as shown in Equation 1.

Equation 1:

L = 20 * Log10 (p/pref)


L – Sound Pressure Level, dB

p – Sound pressure, Pa

pref – reference sound pressure, 0.00002 Pa

Why is this important to know the decibels?  OSHA created a chart in 29CFR-1910.95(a) that shows the different noise levels with exposure times.  This chart was created to protect the operators from hearing loss in work environments.  If the noise level exceeds the limit, then the operators will have to wear Personal Protection Equipment (PPE), or suffer hearing damage.  EXAIR offers a Sound Level Meter, model 9104, to measure sound levels in decibels.  It comes calibrated to accurately measure the sound to determine if you have a safe work environment.

Sound Level Meter

There is a term that is used when it comes to loud noises, NIHL.  This stands for Noise Induced Hearing Loss.  Once hearing is damaged, it will not come back.  To keep your operators safe and reduce NIHL, EXAIR offers many different types of blow-off products that are designed to decrease noise to a safe level.  So, here’s to Alexander Graham Bell for creating the telephone which can be used to contact EXAIR if you have any questions.

John Ball
Application Engineer
Twitter: @EXAIR_jb


Photo of Telephone by Alexas_FotosCC0 Create Commons

General Good Ideas For The Compressor Room

When considering your compressor room all too often the phrase applies “out of sight and out of mind”.  Of course, we all know that is not a good approach to the compressor room or really anything in life.  Unfortunately, many of us take for granted that very system that delivers the power to keep our machines, equipment and tools operating.

Air Compressor
Compressor Room Located Outdoors

So, what can we do keep the ‘lungs” of our plants performing reliably and efficiently?  Since this Blog is about “General Good Ideas For The Compressor Room”, I have some points below for your consideration.

  • Ideally the compressor room should be centrally located to minimize the length of the pipes and allows for easier noise control. With long piping runs leaks become more likely and frictional losses are increased.
  • The compressor room should be sized to allow for easy maintenance and future expansion.
  • For efficient operation air compressors need clean intake air. Intake air that is dusty, dirty or contains gaseous contamination will reduce the efficiency and possibly the longevity of your equipment.
  • The compressor room needs adequate ventilation since air compressors generate significant heat. If excessive heat is allowed to build up it reduces the efficiency of the air compressor raising utility costs, causes compressor lubricant to break down prematurely that could possibly result in increased maintenance and compressor failure.
  • What is the velocity of the air through the main headers? If the speed is above 1200 FPM many dryers have reduced efficiency and speeds greater than this can also carry moisture past the drainage drop legs.
  • Excess friction caused by too small of a diameter piping creates pressure loss, which reduces efficiency and if the compressor is ran above its pressure rating to overcome the frictional losses increases energy consumption, maintenance costs and down time.

Now that your compressor room is shipshape in Bristol fashion, you might think that all is well.  While that may be true, chances are there are other significant additional savings to be had.  EXAIR specializes in point of use compressed air products that are highly efficient and quiet!  If you have any blow-offs that are open tube or howl as loud as the ghost of Christmas yet to come, check out EXAIR’s Super Air Nozzles.  They are highly efficient and quiet, in fact they meet OSHA Standard 29 CFR – 1941.95 for maximum allowable noise and OSHA Standard 29 CFR 1910.242 (b) for higher than 30 PSIG blow-off pressure.  All of EXAIR’s compressed air products are engineered to minimize compressed air consumption and take advantage of the Coanda effect.  Simply stated EXAIR’s highly engineered, intelligent designs entrain (combine) ambient air with the compressed air supply which saves you money!

EXAIR Super Air Nozzle entrainment

EXAIR also offers the Ultra Sonic Leak Detector.  Simply point the device at a suspected leak which are typically found at unions, pipes, valves and fittings from up to 20’ away.   Plants that are not maintaining their plumbing can waste up to 30% of their compressors output through undetected leaks.

EXAIR Ultra Sonic Leak Detector

EXAIR has a complete optimization product line that the Ultra Sonic Leak Detector is in that includes the Electronic Flow Control, Digital Flowmeter’s and a Digital Sound Level Meter.  All designed to either increase the safety or efficiency of your compressed air usage.

EXAIR has 15 other product lines all designed to increase your process efficiency and save you money by using you compressed air supply efficiently.  Why not visit the EXAIR website or call and request a free catalog?

When you are looking for expert advice on safe, quiet and efficient point of use compressed air products give us a call.   We would enjoy hearing from you!

Steve Harrison
Application Engineer
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Image taken from the Best Practices for Compressed Air Systems Handbook, 2nd Edition

Ultrasonic Leak Detector: Because Leaks Won’t Find (Or Fix) Themselves

I once worked in an equipment repair shop with a small and simple compressed air system…just a 5HP single acting piston compressor that sat atop a 50 gallon tank, in the corner by “The Big Truck”. The majority of our work was field service, and management was big on maintaining our service trucks, so we checked tire pressures every Monday morning as we rolled out, and kept a tire chuck handy to ensure proper inflation. It was also used to supply a couple of air guns that were used at our drill press and soldering/assembly station. One morning, I noticed the air compressor was running when I arrived…I thought it was odd, because I knew for a fact it hadn’t been used in at least 16 hours, but that compressed air went someplace, right? We had a leak. Well, at least one.

This was mid-December, and the week between Christmas and New Year’s Day was characteristically slow, and typically devoted to a thorough shop cleaning. We also took the opportunity to get some bottles of soapy water and check for leaks at the handful of pipe fittings that comprised the system…for the uninitiated, if you have a leaky fitting, the escaping air blows bubbles in the soapy water (a cheap, messy way in other words). We found some bubbling, undid those fittings, cleaned them, and applied fresh pipe thread sealant (I don’t want to start any arguments, but I was taught that tape is more of a thread protectant than an effective sealing agent) and, in addition to replacing a couple of well-worn hoses, we were up and running.  And we never heard the compressor running first thing in the morning again.

Not all compressed air systems are as simple as that, though.  Many go from a room with several large & sophisticated air compressors, to corners of every building on the grounds.  Through valves & manifolds, to cylinders, machinery and blow offs, with more connections than you could soap-and-water check in a month.

In those cases, the EXAIR Model 9061 Ultrasonic Leak Detector makes short(er) work of finding the leaks.  With both visual (LED’s on the face) and audible (headphones) indications, even very small leaks are easy to detect with the parabola installed.  The precise location can then be found with the tubular extension.

EXAIR Ultrasonic Leak Detector “hones in” on the exact location of a leak in a compressed air line.

You’ll still have to fix the leaks yourself, but finding them is oftentimes more than half the battle.  And, once fixed, it can be worth a million (cubic feet of compressed air, that is.)

EXAIR’s Ultrasonic Leak Detectors are not only useful for finding compressed air leaks; they’re popular in a variety of other areas:

Additionally, they can be used to identify faulty bearings, brake systems, tire & tube leaks, engine seals, radiators, electrical relay arcing…anything that generates an ultrasonic sound wave.  If you’d like to find out more, give me a call.

Russ Bowman
Application Engineer
EXAIR Corporation
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Sound Power Vs Sound Pressure

EXAIR Intelligent Compressed Air Product dBA ratings as compared to other sounds

When trying to explain or state a number associated with how loud a sound or noise is it can be somewhat confusing or at the very least, ambiguous.  This blog will help to make it clear and easy to understand the difference between Sound Power and Sound Pressure.

Sound Power is defined as the speed at which sound energy is radiated or transmitted for a given period of time.  The SI unit of sound power is the watt. It is the power of the sound force on a surface of the medium of propagation of the sound wave.

Sound Pressure is the sound we hear and is defined as the atmospheric pressure disturbance that can vary by the conditions that the sound waves encounter such as furnishings in a room or if outdoors trees, buildings, etc.  The unit of measurement for Sound Pressure is the decibel and its abbreviation is the dB.

I know, the difference is still clear as mud!  Lets consider a simple analogy using a light bulb.  A light bulb uses electricity to make light so the power required (stated in Watts) to light the bulb would be the “Sound Power” and the light generated or more specific the brightness is the “Sound Pressure”.  Sound just as with the light emitting from the bulb diminishes as the distance increases from the source.  Skipping the math to do this, it works out that the sound decreases by 6 dB as the distance from the sound source is doubled.  A decrease of 3dB is half as loud (Sound Pressure) as the original source.  As an example sound measured at 90 dB @ 36″ from the source would be 87dB at 54″ from the sound source or 84dB at 72″.

We at EXAIR specialize in making quiet and efficient point of use compressed air products, in fact most of our products either meet or exceed OSHA noise standards seen below.

OSHA Noise Level

EXAIR also 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.

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 or any Application Engineer.

Steve Harrison
Application Engineer

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