PPE, respirators.

One situation where air purifying respirators CAN NOT be used is in LOW Oxygen situations. There are other situations as well, toxic atmospheres where the concentration is not known. For these supplied air respirators must be used. There are two main types of supplied air respirators: Self-contained Breathing Apparatus (SCBA) and "air line." Here's what some of that looks like: SCBA and air line. The air supply line (hose) can be up to several hundred feet long. Because SCBA can run out of air, and airlines can break, a popular combination is an air line respirator with an "escape bottle" of air that is only used if the airline pressure drops.

So what kind of respirator do you need? The MSDS or the NIOSH book may tell you, at least for our quizzes and such. In real life, you need a CIH or other expert in the hazard to select these for you.

An important concept in respirator protection is that of Protection Factor. That is simply the concentration of a contaminant outside the respirator divided by the concentration inside. This is determined in the laboratory and assigned to the respirator by the manufacturer after approval by NIOSH. Typical protection factors (from the OSHA asbestos regulations, but these are typical.)

So, if the concentration of hydrogen sulfide is 1000 ppm outside my PAPR, what is the concentration I breathe .

Did we define IDHL earlier? If not, here it is: IDHL (Immediately Dangerous to Life and Health) represents the maximum concentration level of a substance from which one could escape within 30 minutes without escape-impairing symptoms or any irreversible effects. Last important point with respirators is that they have to fit properly. Besides small, medium, and large components of "fit," not all respirator brands will fit all faces, and faces change, for example with age or weight change. A proper respiratory protection program will require periodic fit testing of each individual with their respirator.

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