| Which of the following conditions represents a particular advantage of using a positive pressure type self-contained breathing apparatus in an atmosphere that is immediately dangerous to life or health? |
| A) The equipment is compact and the wearer can work in confined spaces without difficulty. |
| B) The equipment used is lightweight and easy to wear by reducing physical strain on the wearer. |
| C) The average operating time for most air cylinders is over an hour. |
| D) The positive pressure in the face piece prevents contaminated air from entering the face piece. |
