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

Compressed Air Safety with EXAIR’s Intelligent Compressed Air Products

Compressed air is a necessary utility in any manufacturing environment. When used improperly, this compressed air can pose very real and serious dangers to your personnel. It’s imperative that you’re aware of the potential risks associated with the use of compressed air and educate yourselves and your operators to ensure you’re operating safely.

OSHA (Occupational Safety and Health Administration) provides standards designed to mitigate the risks of compressed air usage. If not adhered to, fines can be administered for each infraction. Fines are given out for each individual infraction. Meaning, if you have unsafe blowguns that are used in your facility you’ll get a notice for each individual gun that is identified during an inspection. Inspections aren’t something that happen often, but they will show up unannounced and often at the worst possible times.

OSHA Standard 1910.242(b) discusses the use of compressed air for cleaning and blowoff. It states that the use of compressed air for cleaning purposes is prohibited if the dead-ended pressure exceeds 30 psig. This phrase means the downstream pressure of the air nozzle or gun, used for cleaning purposes, will remain at a pressure level below 30 psig for all static conditions. In the event that dead ending occurs, the static pressure at the main orifice shall not exceed 30 psi. If it does exceed this pressure, there is a very high potential for it to create an air embolism. An air embolism, left untreated, can quickly impede the flow of blood throughout the body. This can lead to stroke, heart attack, and sometimes death.

With this in mind, there are only two options for staying within compliance of this standard. Either install an engineered solution that will reduce the air pressure to less than 30 psig if dead-ended, or regulate the pressure below 30 psig. For the vast majority of operations, regulating the input pressure below 30 psig is useless. The force and flow from the nozzle at this pressure is greatly reduced and likely not enough to be effective in most applications. All of EXAIR’s Safety Air Guns are designed so that the flow cannot be dead-ended. The fins on the Super Air Nozzles are not only useful in amplifying the force by drawing in ambient air, but they also prevent an operator from completely obstructing the airflow.

In addition to being concerned about dead-end pressure, OSHA 1910.242(b) also states that compressed air used for cleaning should include effective chip guarding. By this, they mean that some method or equipment must be installed that will prevent chips and particles from coming back into the eyes or skin of the operator. In addition to offering OSHA compliant nozzles and guns, EXAIR also has Chip Shields that can be installed onto any of our Safety Air Guns. The polycarbonate shields protect the operator from any flying debris while performing a drying or blowoff operation. Simply add a “-CS” to the end of any Safety Air Gun Model number to have a Chip Shield installed on the gun.

Hearing loss due to high noise levels is another common problem in many industrial facilities. Without the use of proper PPE, hearing loss can occur quickly. This is a serious concern as hearing loss is permanent and once the damage is done there’s no way to reverse it. Due to this risk, OSHA strictly enforces standard 29 CFR-1910.95(a).

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.

This directive discusses 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.

The Occupational Safety and Health Act of 1970 does not contain any provisions that allow for the approval or endorsement of equipment. Alteration or the misapplication of what was once a safe piece of equipment would create a dangerous scenario that is out of the control of the original manufacturer. Any nozzles or guns marketed as “OSHA approved” should immediately throw up a red flag. Identifying and implementing a safe, OSHA compliant solution rests in the hands of the manufacturer themselves. If you’ve got questions about compressed air safety or have an existing blowoff in place that does not adhere to this OSHA directive, give us a call. We’ll be sure to recommend a solution that will keep your operators and wallets safe!

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

Understanding Noise: Sound Power Vs. Sound Pressure

Sound Power and Sound Pressure have been covered a few other times here on the EXAIR Blog. Once here by Brian who made the visual correlation in regards to a speaker and a musical instrument. And here by Russ who breaks down how you calculate sound power level with the below equation!
Sound Power Equation
too lou Sound Power Level Equation
All machines generate sound when they are in operation. The propagated sound waves cause small changes in the ambient air pressure while traveling. A sound source produces sound power and this generates a sound pressure fluctuation in the air. Sound power is the cause of this, whereas sound pressure is the effect. To put it more simply, what we hear is sound pressure, but this sound pressure is caused by the sound power of the emitting sound source. To make a comparison, imagine for example a simple light bulb. The bulb’s power wattage (in W) represents the sound power, whereas the bulb’s light intensity represents the sound pressure.
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Light Bulb
Sound power does not generally depend on the environment. On the contrary, the sound pressure depends on the distance from the source and also on the acoustic environment where the sound wave is produced. In the case of indoor installations for example, sound pressure depends on the size of the room and on the sound absorption capacity of the surfaces. For instance, say the room walls don’t absorb all the sound but reflect parts of it, then the sound pressure will increase due to the so called reverberation effect. (reverberation time is broadly defined as the time it takes for the sound pressure to reduce by 60 dB after the sound emitting source has been shut off). OSHA puts the following limits on personnel exposure to certain noise levels:
Working in areas that exceed these levels will require hearing protection.
EXAIR’s line of Intelligent Compressed Air Products are engineered, designed, and manufactured with efficiency, safety, and noise reduction in mind.  If you’d like to talk about how we can help protect you and your folks’ hearing, call us. Jordan Shouse Application Engineer Send me an email Find us on the Web  Like us on Facebook Twitter: @EXAIR_JS Light Bulb image courtesy of  josh LightWork  Creative Commons License

Benefits of Air Nozzles Replacing Coolant Lines used for Air

Over the years, EXAIR has come across many different types of blow-off devices.  We have seen copper tubes, pipes with crushed ends, fittings with holes drilled into them, and modular flex lines.  For compressed air use, these are very dangerous and very inefficient.

A plastic machining center was looking for a better way to blow compressed air.  They were using modular flex lines, similar to Loc-line, which are mainly designed for spraying coolant.  They had 14 blow-off lines in their plant that were about 18” (457mm) long and operated 8 hours a day at 40 PSIG (2.8 bar).  They liked the positioning feature of the flex line, but they could tell by the loud noises that they were wasting compressed air.  So, they contacted EXAIR.

When EXAIR started to manufacture compressed air products in 1983, we created a culture in making high quality products that are safe, effective, and very efficient.  With our Super Air Nozzles, we engineered a way to entrain the ambient air to add mass to the air stream to use less compressed air with a strong force.  This is done by the Venturi method.  We create a high velocity which will make a low pressure at the exit.  The surrounding air is drawn into the compressed air stream increasing efficiency.  We also engineered fins to support OSHA compliance in noise levels and dead-end pressure.  So, if your skin comes in contact with an EXAIR nozzle, the end will not be able to be blocked and allow air to penetrate the skin membrane; even above 30 PSIG (2 bar).  I went over the cost savings and safety solutions that EXAIR’s products could give.

EXAIR Super Air Nozzle entrainment

Since the modular flex lines had a ¼” (6mm) opening, I recommended the model 1100 Super Air Nozzle with a Stay Set Hose.  This recommendation is from experience with these types of blow-off devices.  The Stay Set Hoses will give them that possibility of manually adjusting and re-adjusting the Super Air Nozzles.  The hoses have a “memory” function and will not creep or droop until you physically move it.  They work well to direct air flows at specific target areas like the flex lines above.  For the company above, I recommended the model 1100-9218 which is a model 1100 Super Air Nozzle with an 18” (457mm) long Stay Set Hose.  It was easy to remove the flex line and replace it with a safer and more efficient product

Model 1100-9218

Now, let’s look at the savings.  The Super Air Nozzle with the 18” Stay Set Hose cost $92.00 each.  The flex line is generally around $10.00 each.  But this is not the total cost of ownership.  As an efficiency comparison, the model 1100 Super Air Nozzle will only use 8 SCFM (227 SLPM) of compressed air at 40 PSIG (2.8 bar); and, the noise level is reduced to 70 dBA for each nozzle.  At 40 PSIG (2.8 bar), the flex line had a noise level of 97 dBA and an air usage of 19 SCFM (538 SLPM).

For the annual savings and the payback period, I will look at the electrical cost.  (Since the Super Air Nozzle is using less compressed air, the maintenance and wear on your air compressor is reduced.)

  • The air savings is calculated from the difference in air usage; 19 SCFM for flex line – 8 SCFM for Super Air Nozzle = 11 SCFM savings per blow-off device.
  • With 14 flex lines, the total compressed air savings will be 11 SCFM * 14 = 154 SCFM.
  • To get into the cost, an air compressor can produce 5.36 SCFM/KW of electricity at a cost of $0.10/KWh.  For an annual savings, we have the figures from the information above; 8 hours/day * 250 days * 154 SCFM * $0.10/KWh * 1KW/5.36 SCFM = $5,746.27/year.
  • For a payback period, the model 1100-9218 has a price of $92.00 each, or $1,288.00 for 14 systems.  The flex lines were $10.00 each, or $140.00 total.  The payback period will be ($1,288 – $140) / ($5,746.27/year) * (12 months/year) = 2.4 months.  Wow, what a savings!

Not all blow off devices are the same.  With the customer above, they were able to cut their noise levels, remove the dead-end pressure concerns, and save $5,746.27 a year in compressed air.  If your company decides to select an unconventional way to blow off parts without contacting EXAIR, there can be many hidden pitfalls; especially with safety.  Besides, if you can save your company thousands of dollars per year as well, why go with a non-standard nozzle?  If you are using compressed air for blowing, cooling, cleaning or moving material; you should contact an Application Engineer at EXAIR.  What do you have to lose?

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