A compressor is a machine that pressurises air or gas, commonly used on construction sites to power pneumatic tools.
How does a compressor work?
A compressor draws in atmospheric air and reduces its volume, thereby increasing its pressure. The pressurised air is stored in a receiver tank and delivered through hoses to tools and equipment on demand. There are two main types found on construction sites:
- Reciprocating (piston) compressors — use one or more pistons driven by a crankshaft to compress air in stages. These are common in smaller, portable units suited to light-duty applications.
- Rotary screw compressors — use two helical rotors meshing together to continuously compress air. These deliver higher volumes at a steady pressure and are standard in larger, trailer-mounted site units.
Key performance parameters include free air delivery (measured in litres per second or cubic feet per minute), maximum working pressure (in bar or psi) and power source (diesel or electric). Site compressors are frequently diesel-driven for portability, though electric models are preferred indoors or in noise-sensitive urban areas.
Applications
Compressors supply energy to a wide range of construction activities:
- Pneumatic breakers and drills — demolition and rock breaking.
- Spray painting and coating — applying paint, render or fireproofing materials.
- Air-blown fibre installation — blowing insulation into cavity walls or loft spaces.
- Sandblasting and surface preparation — cleaning steel or concrete before coating.
- Tyre inflation and general site use — maintaining plant and vehicle tyres.
Proper sizing of the compressor to the tools in use is essential to maintain adequate pressure and avoid overloading the machine.
Related terms
- Construction
- Steel
- Insulation
- Concrete
- Ventilation
Want to learn more about construction terms? Visit our knowledge base at fredsdiyplans.com.