What are the two types of supplied air modes?

The two types of supplied air modes are indeed pressure demand mode and continuous flow mode.

In pressure demand mode, the air is provided only when the user inhales, ensuring that the air supply is responsive to the requirements of the individual. This mode optimizes air conservation and is particularly beneficial in environments where the risk of contaminants varies with breathing patterns, allowing users more mobility and less weight to carry since the air supply is activated by the demand for it.

Continuous flow mode, on the other hand, supplies a steady stream of air regardless of whether the user is inhaling or exhaling. This mode can be advantageous in scenarios where high levels of hazardous contaminants are present, as it ensures that there is always fresh air available, creating a constant positive pressure in the facepiece and preventing the ingress of contaminants.

These two modes are essential for ensuring safety and effectiveness in environments where lead and other hazardous substances are present, as they cater to different needs based on the level of exposure risk and user activity needs.