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Key Parameters For Breathing Air Quality

Breathing Air forms an important safety requirement and is often delivered by high pressure reciprocating compressors that are highly efficient in compressing air. Typically, the compressors used are either 3 or 4 stage units that can compress air from atmospheric (0 barg) up to 350 to 414 barg. A 4-stage unit is more efficient and reliable than 3-stages due to the lower interstage temperatures. Typically, the speed and power absorbed by the compressor dictate the charging rate and, in turn, the time to replenish a cylinder.

Breathing Air compressors are constructed to meet the Breathing Air requirements for continuously providing reliable breathing air quality, in line with CGA Grade D/E, NFPA (US) EN12021 (Europe), IS 15879: 2009 (India) or CSA Z1800.1-M85 (Canada) requirements.

Breathing Air Compressors should provide continuous breathing air to fill Self-Contained Breathing Apparatus (SCBA) air systems, Cylinder Cascade systems, Respiratory systems, or other protective equipment.

 

Typically, the air fed into SCBA cylinders is from Breathing Air compressors. However, just because the supply air is coming from an outdoor environment, it does not guarantee the desired quality.

Whatever air is drawn into the system will be compressed and delivered to the cylinders. Water and moisture are normally the biggest contaminant in ambient air, but oil, lubricants, solvents and other vapors can also be present from various external sources.

In order to minimize or eliminate these contaminants and achieve the desired breathing air quality, breathing air compressor packages are normally coupled with a Final Separator and Outlet Check Valve, Purification Chamber(s), and a Pressure Maintaining Valve (PMV). This can be seen in the MAKO Air Purification system found in Figure 1 below. Based on the specific flow requirements, the number of towers can be increased or decreased as needed.

Figure 1: Purification System