Out on the plant floor, workers often innovate on ways to get something done faster or more efficiently, and that's great, but sometimes, these shortcuts can run a company afoul of OSHA regulations. In operations where workers end up getting covered in dust or chips of some sort, they might turn a compressed air gun at themselves in order to clean themselves off quickly. The problem is that this can be exceptionally dangerous depending on the output pressure of the air line, and even whether the worker has an open cut on their skin. And even in more standard use of compressed air, there's many ways companies could accidentally create a dangerous or non-compliant situation. In order to get some insights into the nuances of what is safe and approved, Manufacturing.net spoke with Mark Yorns, the director of engineering with Guardair Corporation.
Manufacturing.net: What is Guardair’s history with the compressed air regulations from the 1970s?
Mark Yorns: Guardair Corporation developed the first “safety air gun” in 1942. It incorporated a safety air shield to protect the operator from “chip fly-back.” This feature was patented, as were further technical innovations which followed. Occupational Safety and Health Administration (OSHA) was established by the US Department of Labor in 1970 to help tackle safety concerns in the workplace. In the early days of OSHA, Guardair worked closely with OSHA officials to craft the standards and consequently was in a unique position to introduce the first safety air gun designed to meet these newly minted regulations.
Manufacturing.net: Can you give a fairly simple overview as to what those regulations require/standardize?
Yorns: The three main regulations that apply to cleaning with compressed air are:
Output Pressure: Factory air lines normally operate between 80 psi and 120 psi. Most pneumatic tools, including air guns, need high pressures to operate effectively. OSHA requires that when an air gun is dead ended (the tip of an air gun is blocked), the static pressure at the point of blockage is no more than 30 psi.
Chip Guarding: Whenever blowing off debris with an air gun in close quarters, workers are subject to chip fly-back. This term refers to the tendency of loose particles or chips to fly back into the operator’s face, eyes or skin. For operations which require close-in work, OSHA requires that effective chip guarding be incorporated into the workplace.
Noise: Excessive noise generated in the workplace can be harmful. To address this problem, OSHA has developed permissible daily noise exposure specifications. Since safety air guns often contribute to high levels of occupational noise, the use of low-noise, safety air guns can be an important component in noise compliance.
Manufacturing.net: From your experience, what are the most common ways that manufacturers are using these compressed air systems incorrectly?
Yorns: Factory air lines normally operate at pressures between 80 and 120 psi (pounds per square inch). Most pneumatic tools, including air guns, require such pressures to operate effectively. However, OSHA regulations require that in the event the pneumatic tool is dead-ended (i.e. if the tip of an air gun is blocked) the static output pressure at the point of the blockage may not exceed 30 psi. Manufacturers incorrectly set their compressed air lines to 30 psi to operate safety air guns rather than maintaining an 80 to 120 psi level. OSHA-compliant safety air guns such as the ones we manufacture at Guardair have built in features that divert the air away from the main orifice if a tip becomes blocked, or make it physically impossible to block the tip. This allows manufacturers to operate between 80 and 120 psi.
End users use air guns or homemade devices to clean that are unsafe and do not meet OSHA regulations. For example we have seen a device constructed out of a ball valve and a piece of pipe. If the tip on this homemade device were to become blocked, full line pressure would be built up behind the blockage — this could be hazardous. Many of Guardair safety air guns feature a Venturi nozzle which has two side ports that serve two purposes. First, it enhances the thrust by drawing in more air from the outside during normal operation. In addition, the side ports vent the pressure should the tip become blocked.
End users thinking they will yield better performance will modify OSHA compliant guns in a way that makes them non-compliant. We have seen users tape the side ports of the nozzle or remove the nozzle entirely thinking it will produce more thrust, but this actually decreases performance. Not only that, but removing the nozzle will greatly increase the amount of air usage
Manufacturing.net: OSHA dead-end regulations ensure a user is not injured if a safety air gun is pressed against their skin. Even so, it’s also not allowed to blow yourself off with these tools. Why? What are the other options?
Yorns: Using air guns to self-clean blows debris into skin, clothing, and potentially unprotected eyes if the operator is not wearing safety goggles Pneumatic vacuums are viable alternatives for self-cleaning. For example, we recently introduced the Personnel Cleaning Station. This high efficiency vacuum runs off standard shop-compressed air and features a proprietary, on-demand air-agitator brush attachment. Thumb-switch activated, the air-agitator loosens and lifts particles airborne where the vacuum sucks them away safely and effectively. It is safe to use and captures the debris versus blowing it back into the air. Additionally pneumatic vacuums have no motor to burn out and are virtually maintenance-free.
Manufacturing.net: Why shouldn’t one self-clean with air guns using compressed air, even if it’s regulated to be “safe”?
Yorns: Using air guns to self-clean blows debris into skin, clothing, and potentially unprotected eyes if the operator is not wearing safety goggles. Should the operator have an open wound, the dust and particles can get lodged in the wound and become infected.
OSHA Regulations Info: http://www.guardaircorp.com/osha-safety/osha-regulations.html
Safety Video Link: http://www.guardaircorp.com/osha-safety/air-gun-safety-video.html