What is the maximum permissible oxygen level in a confined space?

The maximum permissible oxygen level in a confined space is 19.5% to 23.5%. This range is critical for ensuring the safety and health of personnel working in or entering confined spaces.

An oxygen level below 19.5% can lead to oxygen deficiency, which can cause fatigue, impaired judgment, and in severe cases, unconsciousness or death due to asphyxia. On the other hand, levels exceeding 23.5% can increase the risk of fire or explosion, as oxygen-rich environments are highly reactive. Thus, maintaining oxygen levels within this specified range is vital for safe operations in confined spaces.

This understanding is essential when assessing environments such as tanks, tunnels, and other enclosed areas where atmospheric conditions may pose significant risks.