PPE, respirators.
There are two main types of respirators:
The picture above is of an air purifying respirator. The devices on
either side of the respirator are "cartridges" that either
filter out particles or absorb gasses or vapors. There are two main types of
air purifying respirators, negative pressure and PAPR. Using the
negative pressure respirator, the wearer uses "lung power" to pull
air through the filters. The PAPR (Powered Air Purifying Respirator) has a motor driven
blower, usually battery powered, that pulls the air. Both come in "half-face"
and "full-face." Go to this site and look at the variety of negative
pressure, air purifying respirators (be sure to scroll down).
Here's a PAPR
Note the two cartridges on the pack. Air is pulled through the cartridges, pumped into the face mask. There is a one-way valve on the front of the face mask that lets air flow out. Air purifying respirators use various types of filter cartridges. Look at this list and note the many special types of cartridges. One consequence of the many chemical hazards and cartridge types is that you need to know what the chemical you are protecting against and its maximum concentration. If you do not know, NEXT