Which condition must be maintained for safe entry into a confined space?

For safe entry into a confined space, it is essential to maintain safe oxygen levels. In environments with limited space, the atmosphere can fluctuate and may contain hazardous gases, resulting in oxygen depletion or enrichment. Oxygen levels must be maintained within the safe range of 19.5% to 23.5%. Levels below this range can lead to asphyxiation, while levels above can pose explosion hazards. Therefore, monitoring and ensuring that oxygen levels are safe is a fundamental requirement for the safety of individuals entering confined spaces.

The other conditions, while they can contribute to safety, do not directly relate to the most immediate life-threatening hazards present in confined spaces, such as lack of oxygen or presence of toxic gases.