Oxygen is essential to life. However, the presence of oxygen-enriched atmospheres, i.e., air and gas mixtures in which the oxygen concentration by volume exceeds 23.5% at sea level or whose partial pressure of oxygen exceeds 0.23 bar, can lead to accidents.
Not flammable in itself, oxygen supports and accelerates combustion. The potential fire risk increases and combustion is accelerated with the increase in oxygen concentration.
Chemical process engineer working in an ASU or Oxygen Plant should be aware that oxygen is heavier than air and can accumulate on the ground. Moreover, the cold gaseous oxygen is three times heavier than air. Materials that do not burn in air, including most metals and metal alloys, can burn vigorously in oxygen-enriched air or pure oxygen. Oil and grease are particularly hazardous in the presence of oxygen as they can ignite extremely easily and burn with explosive violence.
Source of oxygen, ASU safe operation depends on avoiding oxygen enrichment of the atmosphere; proper use of oxygen; correct design and use of material compatible with oxygen service, and correct operation and maintenance of oxygen systems.
