Air Power Pumps Up Workshops

More and more, air compressors are finding their way into home workshops, basements and garages. Models sized to handle every job, from inflating pool toys to powering such tools as nail guns, sanders, drills, impact wrenches and spray guns, are available through home centers, tool dealers and mail-order catalogs.

The big advantage of air power is that each tool doesn’t need its own bulky motor. Instead, a single motor on the compressor converts the electrical energy into kinetic energy. This makes for light, compact, easy-to-handle tools that run quietly and have fewer parts to wear out.

One of the factors used to designate compressor power is motor horsepower. However, this isn’t the best indicator. You really want to know the amount of air the compressor can deliver at a specific pressure.

The rate at which a compressor can deliver a volume of air is noted in cubic feet per minute. Because atmospheric pressure plays a role in how fast air moves into the cylinder, the rate will vary with atmospheric pressure. It also varies with the temperature and humidity of the air.

To set an even playing field, makers calculate standard cubic feet per minute as the rate at sea level at 68 degrees Fahrenheit and 36% relative humidity. The ratings are given at a specific pressure. If you reduce pressure, the rate goes up, and vice versa.

You also may run across a rating called displacement cubic feet per minute. This figure is the product of cylinder displacement and motor rpm. It provides an index of compressor pump efficiency.

The ratings are important because they indicate the tools that a particular compressor can drive. When choosing a compressor, make sure it can supply the amount of air and the pressure your tools need.