If you’d like to know how efficient (or not,) quiet (or not,) and effective (or not) your current compressed air devices are, the EXAIR Efficiency Lab can help. For more details, we hope you’ll enjoy this short video.
One of the easiest ways to find out if your compressed air guns are safe for operation is by looking at the nozzle. First, take your current compressed air gun and disconnect it from the compressed air line. Second, look directly into the end of the nozzle where the air comes out. If you can see the inside of the nozzle, then your air gun or blow-off device is unsafe. Nine out of ten compressed air guns are considered to be dangerous. In this blog, I will go through the dangers and violations of compressed air guns and nozzles that are very common in the market place.
Occupational Safety and Health Administration, OSHA, is an organization that enforces standards for safe and healthy working environments. They have training, outreach programs, and educational assistance for manufacturing plant. But, they will also enforce these standards with heavy fines for violations. The two most common violations with compressed air guns and nozzles are 29CFR 1910.242(b) for dead-end pressure/chip shielding and 29CFR 1910.65(a) for maximum allowable noise exposure. If you are unfortunate in receiving an audit, the OSHA agent will target your compressed air guns and blow-off devices.
Here is the first example of a nozzle that I would like to discuss. 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 category will include copper pipes, extensions, or worn nozzles. They are dangerous as the compressed air cannot escape if it is blocked by your skin. An air embolism could occur within the body which can cause bodily harm or death. If operated above 30 PSIG (2 bar), these nozzles would violate the OSHA 29CFR 1910.242(b) for dead-end pressure. This is a hazard which can be avoided by using EXAIR Super Air Nozzles and Safety Air Guns. The nozzles are designed to utilize fins to allow air to escape and not penetrate your skin. With EXAIR products, you will not violate this standard even if you go above the 30 PSIG (2 bar).
To counteract the dead-end pressure violation, some nozzle manufacturers created a hole through the side of the nozzle (Reference photo below). This will allow for the compressed air to escape, but, now the issue is noise level. With an “open” section in the nozzle, the compressed air is very turbulent and very loud. They state that 70% to 80% of all hearing loss within a manufacturing plant is caused by compressed air. For this, OSHA 29CFR 1910.65(a) was created to show the maximum allowable noise exposure. This chart shows the time and noise limits before requiring hearing protection. The EXAIR Super Air Nozzles are designed to have laminar flow which is very quiet. With our typical Safety Air Gun, model 1210, the sound level is only 74 dBA; well under the noise exposure limit for 8 hours.
Why do I bring these points up? Because safety is everyone’s responsibility. The National Institute for Occupational Safety and Health, NIOSH, has an overview of how to handle hazards in the workplace. They call it the Hierarchy of Controls (click). This is a means 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 your unsafe compressed air nozzles and guns, EXAIR can help by substituting the hazardous air gun and nozzle with an engineered solution designed with safety in mind.
In my opening statement, I explained a quick and easy method to determine if your compressed air guns are dangerous. To keep your company compliant and safe, EXAIR offers a variety of different types of nozzles and Safety Air Guns to best fit your requirement. If you find that you are using hazardous blowing equipment, you can contact an Application Engineer to find a safe and effective alternative.
I have recently had the pleasure of working with a customer developing a method of delivering air to trapped miners during a multi-man mine rescue mission. The federal government mandates that in the event of an explosion, miners must have a safe place to retreat for a minimum of 96 hours. This system will provide them with a supply of air during that period of time. In the initial stages, they had tried using some old venturis left over from a previous project. While this did work, they weren’t as effective or efficient as they needed. Through a little bit of research, they found EXAIR.
Instead of using compressed air as the source, they’re using cryogenic liquid air. That air passes through a series of cold plates and heat exchangers and gets to the Super Air Amplifier at about 70°F. This air is then carried into the chamber, giving the miners a source of clean air.
EXAIR Super Air Amplifiers utilize a patented shim design that allows the unit to entrain ambient air at a rate of up to 25:1 from the compressed air supply. This balanced outlet airflow minimizes wind shear, producing sound levels that are typically three times quieter than other air movers. The Super Air Amplifiers are supplied with a .003” slotted air gap and can be adjusted by replacing the shim with a thicker .006” or .009” shim.
Do you have a cooling or drying application that could benefit from a Super Air Amplifier? Contact an Application Engineer today to find out how EXAIR can help you save compressed air in your application!
News from the CDC that those of us involved with industrial safety are paying close attention to is the release of their NIOSH (National Institute for Occupational Safety and Health) division’s Hazard Evaluation Program Noise Measurement Database, which contains data obtained through Health Hazard Evaluation surveys performed between 1996 and 2012. It includes hundreds of personal noise exposure measurements (how much noise was received by individuals) and almost as many area noise measurements (how much noise was made.) A comparison of these measurements, of course, is valuable in determining if appropriate measures are being taken to abate the exposure, which is key: there are an awful lot of industrial processes where there’s nothing that can be done about the generation of noise…they’re just simply LOUD. So, they focus on what they can do to limit exposure: Use engineering controls (retrofit open line with engineered nozzles, build sound barriers) , use administrative controls (relocating personnel away from the sound), use personal protective equipment, and spending as little time as possible near the source.
Regardless of what people can get used to, the area noise associated with compressed air use CAN be reduced, while still maintaining the efficiency of the operation. Here’s the deal:
*The most basic form of air blow off is a piece of pipe, tubing, or hose connected to a source of compressed air. When it’s opened to the atmosphere, the compressed air exits with a great deal of force. This makes quite a racket, and the only way to quiet it down is to reduce the air supply pressure. Then you get less force, however, and it might not get the job done.
The compressed air supply (black arrow) uses the Coanda effect when it exits the series of holes recessed in the array of fins (dark blue arrows.) This serves to entrain an enormous amount of air from the surrounding environment (light blue arrows,) which not only results in a high volume flow rate at minimal consumption, but also makes the resultant air flow very quiet.
EXAIR Super Air Nozzles are quiet, efficient, and easy to get…we maintain inventory of anything you see in the Catalog, all available for same day shipment. If you’d like to know how EXAIR products can be easy on your ears…and your wallet…give me a call!
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