Workshops and factories commonly use compressed air to drive power tools.

For the on-site installer, it's less convenient because you need to take your own compressor with you, which in turn would still have to be powered by an electric, petrol or diesel motor.

However, it is a very useful power source when you're using a gun for nailing, stapling or spraying.

It's also handy when the jobsite doesn't have mains power connected and you already own a petrol-operated compressor.

Tools driven by compressed air are called pneumatic tools.

They tend to be more efficient and lighter than equivalent tools powered by mains electricity, because they do away with the need for an electric motor inside the tool.

The compressor itself has a pump which compresses air from the atmosphere.

A receiver, or storage tank, holds the compressed air, and an automatic pressure regulator keeps it at the correct pressure by switching the pump on and off.

If the pressure gets too high, air is released through a safety valve.

Air supply

The volume of air that a compressor can supply is called free air delivery, and is generally measured in terms of litres per minute (L/min).

This is what determines how many tools can be run at any one time from the compressor and what types of tools it is suitable for.

Another important specification is the operating pressure range. This is measured in kilopascals (kPa) or sometimes pounds per square inch (psi).

Different tools operate best at certain pressures, so the operating pressure needs to be checked and re-adjusted if it's found to be incorrect for a particular tool.

It's a good rule to use the minimum pressure required for the tool to operate properly.

This will help the compressor to use less power, and there'll be less wear on the tool.

If you're using a nail or staple gun, it will also reduce the chance of the fasteners countersinking too far and damaging the surface of the material you're firing into.

Routine maintenance for air compressors

Depending on the type of air compressor you're using and the tools you're working with, there will be some routine maintenance procedures that should be followed at certain times.

Your supervisor will tell you what your specific tasks are, but you can see some typical examples under the link below.

Routine maintenance procedures for air compressors

Special safety precautions

Although compressed air is safer than electricity in some respects, it has other hazards that can be just as dangerous.

Below are a few safety guidelines you should follow when using compressed air.

• Always wear safety glasses when using compressed air. This includes blowing out tools or cleaning down work areas with an air hose.
  
  The air will cause particles to fly in all directions at high speed.

• Never point a stream of compressed air directly at anyone's body, particularly bare skin.
  
  Many people have suffered ruptured ear drums, eye injuries, skin blisters and burst blood vessels from either cleaning themselves down with compressed air, or playing practical jokes with it.

• Make sure you secure the loose end of an air hose before turning on the air, to stop it from whipping around when it takes up pressure.