Indoor Air sciences CSMI Practice Exam

If oxygen levels are at 15%, which respirator is appropriate?

1. PAPR

2. O295

3. SCBA

4. N95

The correct answer is: SCBA

When oxygen levels drop to 15%, this represents a significant decrease from the normal atmospheric oxygen concentration, which is around 21%. At such low levels, the risk of hypoxia increases, making it essential to use a respirator designed to provide breathable air rather than relying on the ambient atmosphere. The self-contained breathing apparatus (SCBA) is specifically designed for environments with low oxygen and high contaminant levels. It carries its own supply of breathable air, ensuring that the user is protected in situations where the atmosphere cannot provide sufficient oxygen. This type of respirator is crucial for entering hazardous areas, such as confined spaces, and is mandated when oxygen levels fall below safe thresholds. In contrast, other options like PAPR (powered air-purifying respirator) and N95 masks do not provide a safe solution in environments where oxygen concentration is compromised. A PAPR relies on ambient air, which could contain insufficient oxygen, and an N95 respirator is designed only for filtering out particulates without supplying additional oxygen, making it unsuitable for this scenario. The O295 is not a widely recognized or appropriate respirator in this context. Utilizing a SCBA in environments with critical oxygen deficiency ensures safety and compliance with occupational health standards when facing potentially life-threatening