Thanks to Kirk Edwards, Application Engineer Manager at EXAIR Corporation for his contribution to the UniTherm blog. EXAIR Corporation manufactures compressed air products for industry with a focus on efficiency, safety and process improvement.
My first experiences with compressed air were many years ago and involved welding gas tanks. My friend’s dad was a welding supply salesman in Grand Rapids, MI and we had full access to his welding rigs in the garage. This generally included large tanks of oxygen, acetylene, helium and regular compressed air. We had a few favorite activities with all this gas. One, for when the parents were away, involving helium to lift a plastic bag of acetylene, a long string (wick), and a lighter – enough said? The other was blowing air at each other or using a needle nozzle to blow the air on our skin and watch the cool indent it made. We always knew raising flammable bags of acetylene in the air was a bad idea, but couldn’t resist feeding our youthful pyromania. And we never gave a second thought to blowing air at each other or onto our skin. Come to find out that’s a really bad idea too…
Compressed air is a vital utility in keeping industrial facilities running properly. In many work environments it is second only to electricity for delivering energy within our buildings. Compressed air is common because it is so versatile, it can be used to operate your largest machines or a small handheld tool. Additional benefits include low maintenance cost, use over long periods of time without overheating, and a low weight to power ratio. Most of us are familiar with compressed air, and many of us mistakenly take for granted that it is safe. In the following paragraphs, I will point out a few general safety tips and discuss in detail a couple of OSHA standards that are directly related to compressed air and how EXAIR can help you comply with them. Failure to follow these guidelines could result in injury or a fine from OSHA.
First, here are some common sense safety guidelines when using compressed air.
- Make sure to keep your compressed air equipment in good working condition.
- Inspect the supply lines of your compressed air system by checking any compressed air hoses for damage or cracks. Grease and oil can deteriorate many hose materials so keep them away from spills or areas with grease and oil.
- Compressed air pipes should also be inspected, black iron pipes should be checked for rust and wear, pipes in tight spaces or along machinery should be inspected for damage due to friction or vibration.
- Make sure to check your fittings to prevent accidents from occurring; keep air fittings and couplings tight and clamped securely.
- Never crimp, couple or uncouple pressurized hose. The pressure in the hose should be bled off before making or releasing any connections.
- Always wear proper eye protection around compressed air blow offs.
- Open compressed air pipes and tubes can be loud, always wear proper hearing protection.
Second, OSHA goes in to more detail about proper use and safety of compressed air. OSHA has a specific standard for compressed air: “1910.242(b) Compressed air used for cleaning. Compressed air shall not be used for cleaning purposes except where reduced to less than 30 psi and then only with effective chip guarding and personal protective equipment.”.
Many people assume this means the inlet pressure or the compressed air supply pressure must not exceed 30 PSIG, but that assumption is incorrect. OSHA offers an additional interpretation and I quote “The phrase ‘reduce to less than 30 psi’ means that the downstream pressure of the air at the nozzle (nozzle pressure) or opening of a gun, pipe, cleaning lance, etc., used for cleaning purposes will remain at a pressure level below 30 psi for all static conditions. The requirements for dynamic flow are such that in the case when dead ending occurs a static pressure at the main orifice shall not exceed 30 psi. This requirement is necessary in order to prevent a back pressure buildup in case the nozzle is obstructed or dead ended. See enclosure (1) for two acceptable methods of meeting this requirement. Also, there is no intent to restrict the diameter of the nozzle orifice or the volume (CFM) flowing from it.” Be aware of this OSHA standard to keep your personnel safe. A good engineered air nozzle will meet or exceed this OSHA standard.
Environmental sound levels are also a concern when using compressed air. Many facilities use small open ended copper tubes or open pipes, even pipes with holes drilled along the length to make their own air knives. All of these products violate the above 1910.242(b) standard but also operate at loud sound levels. The overall environmental noise levels increase with these homemade solutions. OSHA also addresses noise levels as a concern for worker safety and health with standard 29 CFR – 1910.95(a).
This standard explains the maximum allowable noise exposure for employees to differing levels of noise. Exposing employees to high levels of noise over time requires personal protective equipment (PPE) to prevent hearing loss. Engineered air nozzles and other engineered compressed air products such as Air Knives and Air Amplifiers can not only prevent a dead end pressure violation, but also reduce or eliminate the need for PPE.
So remember to think safety first when you are considering your compressed air system. It can be dangerous if it is not properly used, maintained, or outfitted. And you might want to keep an eye on your kids, if they are anything like I was, they could use a little education about safety, too.