Basics of Breathing Air


The design and operation of a cylinder refill system for compressed breathing air can be simplified by separating the system into five components:

  1. Compressor
  2. Purification System
  3. Air Quality Monitors
  4. Storage System
  5. Filling Station

These components can be integrated into a single package to form a complete Cylinder Refill System (CRS), or they can be individually combined to form a component-built or modular system.

Once interconnected, the components operate as follows:

  • The compressor draws ambient air through a strategically located air intake and compresses it through multiple compression stages. The compressed air is then routed to the purification system for processing.
  • The purification system processes the compressed air stream to ensure that delivered air meets breathing air quality. The mechanics of the purification process includes mechanical separation, impingement, adsorption, absorption and catalytic conversion. During the purification process visible contaminants such as oil, water and particulate matter, down to a size of 1.0 micron, is removed. Finally, gaseous contaminants such as water vapour, hydrocarbons and carbon monoxide are removed.
  • Air monitors are utilized to ensure that the air quality is maintained in accordance with industry standards. Compliance with established regulations is facilitated through such methods as continuous in-line monitoring and/or periodic sampling.
  • Once purified, compressed breathing air is then stored in the storage system. The storage system consists of high pressure air receivers or containers that store the purified, pressurized air until needed. High-pressure air is transferred from the storage system into breathing apparatus cylinders by the filling station.
  • The filling station is designed to fill self-contained breathing apparatus (and/or self-contained underwater breathing apparatus) cylinders easily, efficiently and safely. A filling station can be very simple or quite complex. A simple filling station may consist of a single fill hose. A complex filling station may consist of both an air control panel, utilized to monitor and control the system air flow and pressure, and a fill container enclosing BA cylinders during the filling process in order to protect the operator and by-standers.

The following abbreviations are commonly used in conjunction with compressed breathing air systems:

  • BA=Breathing Apparatus, SCBA and/or SCUBA
  • SCBA=Self-Contained Breathing Apparatus
  • SCUBA=Self-Contained Underwater Breathing Apparatus
  • CRS=Cylinder Refill System

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