What is the minimum level of oxygen that should be present before entering a confined space for repair work?

The minimum level of oxygen that should be present before entering a confined space for repair work is 21%. This is critical because normal atmospheric air contains approximately 21% oxygen, which is necessary for human respiration and to ensure that individuals can perform their tasks safely without the risk of hypoxia (a deficiency in the amount of oxygen reaching the tissues).

Levels below 19.5% oxygen can lead to serious health risks, including loss of consciousness and even death, due to inadequate oxygen supply for metabolic processes. Therefore, maintaining an oxygen level of at least 21% is essential to ensure a safe working environment within confined spaces.