What type of air supply is commonly used in SCBA systems?

The use of compressed air suiting specific purity standards in SCBA systems is essential for ensuring the safety and effectiveness of the apparatus during operations in hazardous environments. Compressed air is typically utilized because it provides an adequate supply of breathable air for the wearer, while also maintaining high safety standards.

In SCBA applications, the compressed air must meet specific purity standards to ensure that it is free from contaminants such as carbon dioxide, chemical particles, and other toxic substances that could be present in environments where SCBAs are necessary. In environments that are immediately dangerous to life or health (IDLH), this level of care in selecting air supply is crucial to protect the user's respiratory system.

Filtered atmospheric air and non-pressurized ambient air would not provide adequate safety, especially in toxic or low-oxygen environments, as they may contain harmful pollutants or insufficient breathable oxygen. Pure oxygen is also not used in SCBAs because high concentrations can be fire hazards and may pose additional risks to the user's health. Thus, using compressed air that meets specific standards not only supports the wearer's immediate breathing needs but also adheres to stringent safety regulations, making it the most appropriate choice for SCBA systems.