What must the oxygen content be for safe entry into tanks?

For safe entry into tanks, the oxygen content must be around 21%. This is considered the normal atmospheric level of oxygen and is essential for human survival and safety. An oxygen concentration lower than this can lead to an increased risk of asphyxiation, as the body may not receive sufficient oxygen to function effectively. Furthermore, levels of oxygen that are too high can pose a fire hazard, increasing the risk of ignition for flammable materials that might be present.

The choice of 21% ensures that the atmosphere is not only safe for breathing but also minimizes potential hazards associated with oxygen deficiency or enrichment. In situations where the oxygen levels fall below safe thresholds, monitoring and remediation measures must be implemented to ensure a safe environment for tank entry and work.