To what oxygen level should you drop the O2 level when sealing off an area?

When sealing off an area in a mining environment, it is essential to reduce the oxygen level to a point where it minimizes the risk of combustion or supports only the most basic respiration. The recommended oxygen level for sealing off an area is typically around 16%. This level is low enough to help prevent the ignition of combustible materials while still allowing for some level of safe breathing for any potential survivors.

Reducing the oxygen concentration below this level makes conditions more hazardous for fire events, as most fires require oxygen levels above approximately 16-18% to sustain combustion. Maintaining an oxygen level of 16% effectively creates a controlled environment that is safer in the event of an emergency, such as a fire or explosion, while still being mindful of any personnel who may need to enter the area for rescue purposes.

The higher oxygen levels, such as 18%, 20%, and 21%, could increase the risks associated with fire and combustion in a sealed environment, which is why they are not appropriate choices. They could support fire more readily, thereby endangering life and property.