FIXED: This type of system is usually driven by a compressor that draws in fresh air and stores it in an air tank. Connection points are normally mounted on the walls of the premises.

PORTABLE: This type is usually either a small cylinder with compressed air carried on your back, or a large cylinder or cylinders on a trolley.

Remember that both fixed and portable systems can feature respirators with back-up filters. This means that if the system shoiuld fail for any reason, the respirator still works as a filter device while you get out of the hazard area.

Note: this can only be achieved if you are using tight-fitting face pieces. Air hoods and helmet type respirators cannot be fitted with back-up filters.

If you are using a compressor, it is very important that the air intake is placed in a clean-air area, and that there is no risk that the air intake can be polluted. For instance, having the air intake placed in a car park or near a kitchen or canteen is not a good idea.

The air intake should be constructed in such a way that no rain, water, leaves, grass, birds or other things can enter the system.

The compressor must be able to power all air tools and all breathing outlets, if used. On the other hand, the entire system must be rated for a greater pressure than the maximum capacity of the compressor.

Note: the delivery capacity of the compressor must be calculated according to the number of users and the nature of tools connected. At the very least, for minimum requirements the compressor should be capable of delivering 0.7 m³/min (25 cubic feet/min)

A holding tank behind the compressor means that the air supply will be consistent, smooth and of even pressure. I also saves power, as it means that the compressor only has to work when the air pressure inside the tank falls below a certain level.

The whole system must be fitted with one or more over-pressure valve. This valve prevents the system from rupturing in case of a blockage, and is an important component that protects both people and equipment. Over-pressure valves should be checked regularly.

The compressor can generate water, oil mist and other impurities. A main trap will capture these before the air enters the supplied air system. The trap should be checked regularly.

Air-driven tools can consume a lot of air at high pressure. Make sure all connectors are secure, intact, of good construction. The capacity (pressure and air flow) of the compressor/tank should be higher than all air tools' consumption put together. On the other hand, the entire supplied air system (hoses, tubes, pipes, connections, filters etc.) must be rated higher than the maximum capacity of the compressor.

The entire air supply pipe should be mounted at a slight incline, up from the holding tank. This is so that all condensation water will run back into the water traps (see below). Condensation water can damage air tools and ruin delicate work such as spray painting.

Condensation water traps should be used throughout the system. The traps should be drained regularly and checked often.

If the supplied air system is to be used for breathing air as well as tool air, a high-efficiency breathing air filter must be installed. The purpose of the filter is to clean the compressor/tank air of moisture, oil mist, odours and other impurities that may be harmful to humans. NEVER USE UNPURIFIED AIR FOR BREATHING.

Ensure that there is no possibility of connecting any breathing device (respirator, hood etc.) to unpurified tool air. There are two options in the system design:

Option 1: All air in the entire system is of breathing quality (that is, the air filter is placed before all tolls and respirators).

Option 2: Design a split system where tool air is unpurified and breathing air is filtered. In this case, breathing air couplings and connectors must be incompatible with tool air sockets. There must be no risk of accidentally connecting a respirator or hood to the tool air system.