What must be present when using a Type C supplied air respirator?

A Type C supplied air respirator is designed for use in environments where the air supply may be compromised, particularly in situations where there are high levels of contaminants or insufficient oxygen. When using this type of respirator, a reserve air supply is crucial because it serves as a safety measure to ensure that the worker has access to breathable air in case the primary air supply fails or if there is an unexpected situation that requires immediate evacuation.

The presence of a reserve air supply helps maintain a continuous and safe breathing environment for the user, thereby enhancing their safety while working in potentially hazardous conditions. This measure is essential because if the primary air supply were to be interrupted, the reserve would provide a buffer, allowing the individual time to exit the hazardous area.

The other options, while they may have their own safety roles in different contexts, do not fulfill the same critical requirement as a reserve air supply in the context of using a Type C supplied air respirator. Air filters, for example, are used for filtering contaminated air but are not applicable when the air quality is too poor for filtration alone. A backup air tank can provide additional air but is not a requirement for the operation of a Type C system. An oxygen mask is utilized in scenarios where supplemental oxygen is needed,