Hearing loss due to high noise levels is a 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).
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.
Hearing loss can occur in as little as 30 minutes when exposed to sound levels 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 protection hefty fines will be soon to follow. 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.
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!
One of the most dangerous things you can do is depressurize a line full of a pressurized gas. If the charge pressure is high enough, it’s going to come roaring out, with tremendous force and velocity. Anything in its path is subject to that force & velocity. Objects small enough to become entrained in its flow can become hazardous projectiles. The noise it creates can be literally deafening. If the point of discharge is accidentally jammed against your body, the pressure can get through your skin. As if that wasn’t scary enough, the gas then has a free path inside your body…they call that an embolism, and it can kill you.
Why on earth would anyone want to do that on purpose? Well, it happens every day, in factories, businesses, and homes all over the world, when people operate compressed air operated blow off devices. Of course, there are numerous factors that can drastically reduce the risk of injury associated with compressed air blow off devices.
One of these is mandated by the government. The Occupational Safety and Health Administration (OSHA) regulates the outlet pressure of any compressed air device used in industry for cleaning purposes. Keeping the outlet pressure low mitigates the risk of puncturing the skin. There are various methods of compliance with this regulation:
Regulate the supply pressure to less than 30psig. This absolutely complies, but it severely hampers your ability to get much done, as the air flow will be too weak to blow off anything but lightweight debris, from a smooth, dry surface, with the device pretty much right up on top of it.
Use a device that provides a relief path for the air flow if it was to become blocked or obstructed. EXAIR engineered Air Nozzles are designed to do this…you can supply them with higher pressures but they provide a relief path for the air, meaning they can’t be blocked or dead-ended.
Regardless of the compressed air supply pressure, the design of EXAIR Super Air Nozzles prevents a dangerous pressure from developing at the outlet.
The same regulation – OSHA 1910.242(b) – also addresses the airborne projectile problem by mandating the use of appropriate chip guarding. There are a number of ways to do this as well…chief among these is personnel protective equipment (PPE). At a minimum, you absolutely, positively should be wearing safety glasses with side shields whenever you have a blow off device in your hand (and so should anyone working near you, for that matter). If an operator is blowing off small, sharp shards, an OSHA inspector is probably going to get grumpy if they’re not wearing a full face shield, long sleeves, and maybe even a durable apron. Alternately, the blow off device could also be fitted with guarding as well…something like the Chip Shields that are available for most EXAIR Safety Air Guns. These polycarbonate dish-shaped shields fit on a rigid extension between the Safety Air Gun and the Super Air Nozzle, and can be positioned at an optimal distance to keep solid debris and liquid being blown off away from the operator.
Chip Shields are available for most EXAIR Safety Air Guns (left to right): VariBlast Precision & Compact, Soft Grip, and Heavy Duty Safety Air Guns……and others. These are just a few examples of blow off devices that can be successfully fitted with an EXAIR Chip Shield.
Another OSHA Standard – 1910.95(a) is there to protect operators against that literally deafening roar associated with unregulated discharge of compressed air. While cross-drilled nozzles (most easily seen in the lower left hand image above) provide a relief path to keep the outlet pressure at a safe level if they’re dead-ended, they’re still for all intents & purposes, an open-ended blow off…and quite loud. EXAIR Super Air Nozzles reduce the sound level of their air flow by design…the entrained air (which makes them so efficient) also forms a lower velocity barrier layer in the flow, which makes them extraordinarily quiet. In fact, all EXAIR Super Air Nozzles except our largest High Force models comply with OSHA limits for 8 hour noise exposure limits. Most callers that we talk to about applications for those are in areas where hearing protection is mandated anyway…if you need more than 4 pounds of blowing force, you’re probably wearing ear plugs already.
If you use compressed air for cleaning, drying, blow off, etc., you really need to do it safely, and in compliance with published & established safety standards. OSHA WILL fine you otherwise, and, even worse, someone could get hurt. EXAIR Corporation is devoted to helping you get the most out of your compressed air usage, and safe use is key to that. If you have any questions about it, give me a call.
Russ Bowman, CCASS
Application Engineer EXAIR Corporation Visit us on the Web Follow me on Twitter Like us on Facebook
If you look at operating costs alone, compressed air can be just about the most inefficient method there is for cleaning parts. If you just look at the risks, it’s potentially very dangerous too. Don’t even get me started on the insufferable noise it can make.
For cleaning parts, most folks are familiar with the use of an air gun. You can find the simplest of these in many industrial settings: a valve (often in the form of a handheld trigger device) fitted with a nozzle of some sort (often in the form of an open ended tube, pipe, or fitting to focus or direct the air flow). These have all three of the “downsides” I opened this blog with. Of course, these concerns can be mitigated to a high degree by using the right tool for the job. That’s where engineered products like EXAIR Safety Air Guns come in. Let’s look at how we can address these three “downsides”:
Efficiency: This is all about compressed air consumption. In the simplest of air guns mentioned above, consumption is only limited by the passages in the valve (or trigger) and the discharge fitting…and those limits are usually negligible. Modifying the ends (see examples below) to focus the air flow usually has minimal effect, because you’re not appreciably changing the total cross sectional area of the discharge opening:
Here are a few modified thumb trigger air guns that were sent in for Efficiency Lab testing. Left to right, compressed air consumption at 80psig supply pressure was 34.2 SCFM, 30.9 SCFM, and 28.2 SCFM. For comparison (more on this later,) EXAIR Model 1210 Soft Grip Safety Air Gun uses only 14 SCFM and generates a very similar flow pattern.
Safety: Remember learning about kinetic and potential energy in grade school? Well, when you compress air to 100psig, fitting all that air into a much smaller space creates a TREMENDOUS amount of potential energy:
The block on the left represents a cubic foot of air at atmospheric pressure. The one on the right represents how much space the first one takes up when compressed to 100psig. The energy imparted by this process HAS to be handled with care.
One problem with the thumb guns above is, if you were to jam into the palm of your hand and pull the trigger, a large component of that potential energy (pressure) turns into kinetic energy (force)…more than enough to break the skin and cause a potentially fatal condition known as an air embolism. In the United States, OSHA (Occupational Safety and Health Administration) regulates compressed air devices used for cleaning purposes. All EXAIR Safety Air Guns comply with Standard 1910.242(b) by providing a relief path to ensure that it cannot be dead ended, and thus never create over 30psi measurable at the outlet)
EXAIR Super Air Nozzles cannot be dead ended, ensuring the outlet pressure won’t reach OSHA limits, regardless of supply pressure.
Noise: Another problem is, another component is turned into sound pressure…discharging air from a direct opening is quite loud. OSHA standards address these with limitations on outlet pressure and sound level. All EXAIR Safety Air Guns comply with Standard 1910.242(b), which limits the outlet pressure (by providing a relief path to ensure that it cannot be dead ended, and thus never create over 30psi measurable at the outlet) and all but our largest Super Blast Safety Air Guns comply with Standard 1910.95(a) limits for continuous 8 hour sound level exposure.
Which brings us to the topic of this blog: How exactly did THEY (our customer who used to use the thumb guns above) select the right Safety Air Gun, and how can we apply that to getting the right Safety Air Gun for YOU?
These steps aren’t all-inclusive, and they don’t necessarily need to be followed in order, but if you call an EXAIR Application Engineer about selecting a Safety Air Gun, here’s what we’re gonna talk about:
Ergonomics: We offer five distinctive styles of Safety Air Guns:
From small part cleaning by hand, to wide area blowoff, and all points in between, EXAIR has a Safety Air Gun for most any application.
Our thumb gun user (as I alluded to above) chose the Model 1210 Soft Grip Safety Air Guns (top right). They had a number of typical industrial applications where the operators had the parts or surfaces to be blown off right in front of them. They liked the integral storage hook and rubberized hand grip, but the VariBlast Compact (top middle) or Heavy Duty Safety Air Guns (bottom left) were also considered. The VariBlast Precision (top left) and Super Blast Safety Air Guns (bottom right) were too focused or more powerful, respectively, than needed.
Airflow pattern: Honestly, I could make a good case for this being the first consideration. Selection of any blowoff product – be it an Air Nozzle, Air Amplifier, Air Knife, Air Wipe, etc., will largely depend on the size and shape of the airflow.
variety of airflow patterns…and effective distances…are available from EXAIR’s comprehensive line of Super Air Nozzle products.
For the most precise, focused blowoff, our Atto Super Air Nozzle (top left) is a great choice. It’s available on:
Super Air Nozzle Clusters (bottom left) create higher force & flow, and still keep it in a more concentrated, tighter pattern. They can be installed on:
When stubborn, heavy, and/or LOTS of debris needs to be absolutely, positively blown off RIGHT NOW, our High Force Super Air Nozzles may be just what you need. Our largest; Model 1120 1-1/4 NPT Super Air Nozzle, is shown (above right). The High Force Super Air Nozzles are offered on:
Soft Grip or Heavy Duty Safety Air Gun (up to 3.3 pounds of force over a 6.3″ wide area @12″ away)
Application specific concerns: Everything we’ve discussed so far has involved aiming the blow off stream away from the operator, in the direction the device is aimed. In addition to wide variety of engineered Air Nozzles, EXAIR offers a number of options for these products:
If you’re looking for a portable, hand-held compressed air blow off product that’s quiet, safe, and efficient, look no further than EXAIR Corporation’s extensive line of Safety Air Guns. If you’d like to find out more, give me a call.
Russ Bowman, CCASS
Application Engineer EXAIR Corporation Visit us on the Web Follow me on Twitter Like us on Facebook
