A steady supply of clean and dry air is required to power and protect pneumatic components in machines, equipment and processes and to ensure their proper operation. All pneumatic motion, including clamping, positioning, pushing, lifting, etc. requires clean and dry air with enough flow to provide the required pressure. The process of filtering, regulating (and sometimes lubricating) this compressed air is known as "Air Prep".
Facilities often have a main "plant" or "shop" compressor, which feeds a network of pipes, fittings, and devices. These components may introduce particulates, moisture or other contaminants. Even if the shop has dryers, filters, moisture separators and regulators at (or near) the compressor, it is also wise to provide some air prep at the machine level also. At a minimum, air prep at-the-machine should include filtering, regulating, and some form of shut-off or "air dumping" for safety and routine maintenance.
In larger facilities the air supply may be taken for granted. Without adequate air flow the pressure will sag during use, especially during high demand periods. Oversizing the shop plumbing is almost always a good idea, but also make sure the compressor is sized for the current demand, or better yet: invest in a larger, more efficient systems when possible to plan for future growth.
And oversizing the air preparation system is another smart move, providing excess capacity for additions or unanticipated demands. The air prep system should start with a manual shutoff relief valve with lock-out to remove air for maintenance. For additional safety, OSHA also requires air to be dumped during an emergency stop or other safety event. Consider an electrical soft start valve that dumps air when power is removed. A soft start valve also keeps the pneumatic equipment from banging when air is applied.