What are the upper and lower limits for safe oxygen levels in confined spaces?

In confined spaces, maintaining safe oxygen levels is critical to prevent hypoxia (lack of oxygen) or hyperoxia (excess oxygen), both of which can lead to serious health risks. The upper and lower limits for safe oxygen levels are based on industry standards and safety regulations.

An oxygen concentration between 19% and 23% is generally considered safe for human occupancy in confined spaces. Levels below 19% can lead to impaired cognitive and physical performance, potentially endangering individuals in that environment. Conversely, oxygen levels above 23% increase the risk of fire and explosion, given that higher oxygen concentrations can accelerate combustion.

These specific limits are established by organizations such as the Occupational Safety and Health Administration (OSHA) and the National Institute for Occupational Safety and Health (NIOSH) to ensure safety in working environments where oxygen levels can be compromised. This ensures that individuals working in confined spaces remain safe while performing their tasks.

The other ranges provided do not align with these established safety standards. For instance, values below 19% or exceeding 23% pose significant health and safety concerns, making them unsuitable for safe operations in confined spaces.