When compared to other types of equipment on your jobsites, an air compressor hardly seems hazardous. After all, how can air be dangerous?

"Think of compressed air as stored energy," says Tom Grau, product-line R&D department manager, MMD Equipment. "Consider it takes almost 9 cu. ft. of air to make 1 cu. ft. of compressed air, and you get some idea of the energy that is stored not only in the air compressor's tank, but also in the hose connected to the tools you're operating.

"This energy did not get compressed easily," he continues. "For a 185-cfm machine, it takes over 50 hp at 3,000 rpm to confine that energy. Therefore, the sudden, uncontrolled release of this energy could have devastating results."

This is why you need to take note and pay attention to the industry's safety rules for compressed air. You also need to give the compressor a thorough "once over" before it leaves your equipment yard.

Precautions prior to use

According to Harold Wagner, national sales manager, Kaeser Compressors, the compressor, air hose and air tools need to be inspected thoroughly prior to use. Here are some additional precautions:

Compressor —

• Ensure that shutdown devices and pressure and temperature gauges are working.
• Check for the correct tire pressure and excessive tread wear. Improperly inflated tires can affect road handling, damage the tire and make transportation dangerous.
• Check that all lights are working properly.

Air hose —

• Use hose rated for the maximum compressor pressure and flow.
• Make sure the hose and compressor discharge fittings match. Always use the safety pin to prevent the fittings from disconnecting. If a pressurized air hose breaks loose, "fish tailing" could injure workers and damage equipment.
• Do not allow your hoses to be run over by vehicles or stored improperly. Cracks or weak spots are not only wasteful, but also dangerous to the operator.
• Depressurize the hose prior to disconnecting.

Air tools —

• Inspect all air tools to ensure proper operation. Make sure all components are tight and no parts are missing or damaged.
• Consult your tool steel catalog for proper tool steel selection and application.
• Check air pressure to ensure proper working pressure of the tool.
• Always purchase the best air tool lubricant available to prolong equipment and tool steel life.

In addition, Grau indicates that the tow vehicle needs to meet certain criteria, plus the compressor must be hooked up to it properly. For example, you should confirm that:

• the tow vehicle is of sufficient size to be able to stop the compressor in the event of an emergency or "hard-brake" situation;
• the tow vehicle's hitch is at the correct height so the compressor is towed as close to level as possible;
• safety chains are properly crossed and connected, and are not so long that they drag on the road;
• electrical connections are properly matched and made, especially if the compressor has electric brakes.

Precautions during use

According to Marc James at Ingersoll Rand, there are several points to keep in mind to avoid common compressor danger zones.

"Before disconnecting a hose from the tool or the compressor, make sure all the pressure has been released," he says. "Another pitfall is hose whip, which can occur when a hose is cut or torn. The hose turns into an uncontrolled whip. This can be prevented by using a whip-check cable [also known as break-away protection], such as a short length of cable or chain attached to the tool and hose."

Never use a hose that shows signs of damage, and only use hose fully rated for the pressure of the machine. Keep the hose out of the way to avoid a tripping hazard. And protect it from being damaged — especially by the tools being used.

You should also be aware of the availability of a safety check valve. This is usually an option or aftermarket addition to the compressor. It is designed to immediately shut off the air supply should a break in the hose occur, making it a wise investment.

Although it may seem like common sense, anyone operating a compressor should be aware of proper startup and shutdown procedures. "The proper sequence for startup is connecting the air lines, starting the compressor, then opening the service valves before working," says James. "When you shut down, you go in the opposite sequence: stop working, close the service valves, turn off the compressor, then clear the lines of pressure. Never shut down without closing the service valves."

In addition, the emergency stop should only be used in an actual emergency. "It shouldn't be used just to turn the machine off, as the compressor could be damaged," James explains.

Dos and don'ts of operation

It's not uncommon to use compressed air for quick cleaning and as a casual way to remove dirt and dust. However, most compressors deliver air at approximately 110 psig. Even the smallest piece of debris (i.e., metal shavings, wood chips or gravel) flying through the air at this velocity can be dangerous.

The seemingly simple practice of using compressed air for dusting surfaces or "cleaning yourself off" can cause permanent injury. In fact, it's possible for compressed air to penetrate the surface of the skin and cause fatal embolisms. Many end users don't know that using compressed air over 30 psig for these purposes is also a serious OSHA violation. As such, do not point compressed air lines at people for any reason.

Anyone assigned to operate a compressor should be instructed to use the proper personal protection equipment. "Goggles, safety shoes, gloves and hearing protection are a must when operating construction tools," says Wagner. "Other applications may require additional gear."

Grau adds, "Keep in mind that released compressed air could send loose objects flying, so you will want to make sure your arms, legs and body are protected."

Also keep safety in mind when adjusting or servicing the machine. "The equipment's well being is secondary," says Wagner. "[You] should never attempt to repair or troubleshoot a compressor in a manner that could jeopardize health or safety."

When servicing the compressor:

• Follow manufacturer's recommendations for proper operation and routine maintenance. Only trained technicians should adjust compressor components.
• Do not adjust safety, blow-off or control valves without referring to the operator's manual. Improper adjustments can, for example, cause "air explosions" from the safety valve, startling and perhaps injuring even experienced operators.
• Do not change filters or check fluids while the compressor is running or pressurized. Spraying fluids, such as oil, can cause burns or serious injury.
• Inspect the inside of the separator tank and the oil separator filter at least once per year, regardless of the machine hours. Condensation that has not been properly drained can clog the separator filter, causing the potential for a flash fire.

For more information, visit www.ForConstructionPros.com

Information provided by MMD Equipment.