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.
So making sure you are in compliance with 1910.242(b) is truly a life and death situation. Most people believe that lowering the pressure to the blow off device is the only method to keep their operators safe from an air embolism. However this can become a problem when you really need the force of greater than 30 PSIG to complete your operation. We at EXAIR want to give you the flexibility to run at any pressure with out the risk of building that 30 PSI of dead-end pressure! We do this with our line of Intelligent Compressed Air® nozzles! All of EXAIR’s Air Nozzles 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.
Another great example of this is our 2″ Flat super air nozzle. The design not only allows the nozzle to amplify the air flow in the blast of air, the over hang will not let the dead end pressure build as it can escape around the edges and bottom!
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!
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.
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.
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
Compressed air is a very versatile utility that can be used for applications in cooling products to cleaning off workspaces and products. That is where OSHA 1910.242(b) comes into play; this OSHA standard states that compressed air used for cleaning shall not be used except were reduced to less than 30 psi and then only with effective chip guarding and personal protective equipment. This standard is in place because in the event a dead end occurs, the static pressure at the main orifice can potentially force the high pressure air into someone’s bloodstream and cause an air embolism, which if left untreated can impede the flow of blood in the body and lead to a fatality.
Keeping that in mind there are two ways you can go about these cleaning applications and still stay in compliance with the OSHA standard. The first way is to regulate the air pressure in your pipe down to below 30 psig. But for the majority of applications this is not an effective solution as pressure does equate to the amount of force that can be produced from the system. The second solution is to use a nozzle that is engineered in a way the it cannot be dead ended. This means that the nozzle is designed in a way that no matter how hard you try the air coming out of the nozzle will be ejected into the atmosphere and not through skin.
Take EXAIR’s Air Nozzles for example, the fins and orifice placement are designed in a way that allows air escape air into the atmosphere. Once air has exited an orifice into atmospheric conditions the pressure becomes 0 psig but retains the velocity and higher volume from the higher compressed air inlet pressure which produces force.
In addition, OSHA 1910.242(b) also talks about the use of effective chip guarding, which simply means some method or equipment shall be installed that prevents particles from flying back and hitting the operator. If you look EXAIR’s Safety air guns you will notice that we offer Chip Shields. By simply adding “-CS” to the end of a part number for a Safety Air Gun you can help prevent injuries from flying particles in blow off applications.
If you have any questions or want more information on compressed air safety and OSHA related standards. 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 Visit us on the Web Follow me on Twitter Like us on Facebook
Safety is a key part of our culture at EXAIR Corporation. We have regularly scheduled, all-hands required, safety training on a number of topics. Our Order Entry team can likely tell you as much about our lockout/tagout procedures as our Machinists can. Nobody even thinks about entering The Shop without safety glasses, and it’s not just because of the signs.
OSHA 1910.242(b) states that “Compressed air shall not be used for cleaning purposes except where reduced to less than 30 p.s.i. and then only with effective chip guardingand personal protective equipment.“ (emphasis mine) All EXAIR Intelligent Compressed Air Products are engineered to meet the requirements of the first part (30psi outlet pressure to prevent dead ending…we’ve written about that numerous times, including here, here, and here) and we can also provide pre-installed devices to satisfy the second part: the EXAIR Chip Shield.
Any EXAIR VariBlast or Heavy Duty Safety Air Gun can come fitted with a Chip Shield, and any Soft Grip Safety Air Gun, except for those with Stay Set Hoses, can as well. Safety Air Guns with Back Blow Nozzles automatically come with a Chip Shield. The principle is simple: a clear polycarbonate (so you can still see what you’re doing) round disc slips over a short (or long if you want) pipe extension between the gun & the nozzle. It’s fitted with a rubber grommet so you can position it to where it’s most effective – sometimes that might be closer to the part being blown off; sometimes it may be back a little closer to the operator.
If you already have an air gun that’s doing the job, you can easily add an EXAIR Chip Shield to it. They’re made to fit a wide range of extension diameters, and can even come with the extension if you need it. We also stock a number of adapter fittings; if you know what threads your air gun has (or if you can send us some photos) we can quickly & easily spec those out for you.
Since 1983, EXAIR Corporation has been manufacturing quiet, safe, and efficient compressed air products for industry (emphasis mine.) If you have concerns or questions about safety in regard to your compressed air use, call me.
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