Respirator Definitions
A respirator is a personal air purifier or air supply designed to be used in environments where the air is unhealthy or hazardous. Respirators can vary from simple, passive systems designed to filter out dust to extremely sophisticated systems that can protect the wearer from viruses, radioactive particles, chemical weapons and other potentially lethal pollutants.
Respirator Basics
At its most basic, a respirator is a fine cloth held over the face by a mask. Fibrous materials such as wool and cotton have very small holes in them. When the wearer breathes in through the respirator, large particles of dust and dirt are pulled by the air currents toward the respirator filter. While the air can pass through, many of the particles are too big and get stuck in the holes. Others may be small enough to fit through but pass close enough to stick to the holes in the respirator anyway.
Advanced Filter Materials
Many respirators use specialized filters made out of materials designed to catch as many particulates as possible. Activated charcoal filters have an electronic charge that causes particles to latch on to the filter as they pass by. HEPA filters are made out of a random weave of fibers designed to create air turbulence. When particles of dust, smoke or other pollutants are pulled through the filter, the turbulence makes them bump into the fibers, where they latch on and stick. HEPA filters can clean well over 99 percent of particles out of the air.
Specialized Respirators
For really dangerous tasks or repetitive exposure to pollutants, people often use specialized respirators designed to combat a particular hazard. Many of them are powered respirators, using a fan to blow air past a series of filters designed to trap a particular type of pollutant. Even more specialized are the self-contained breathing apparatus respirators. Firefighters and other people subject to extreme environments sometimes dispense with filters altogether and simply wear tanks of pressurized air on their backs connected to breathing hoses. This eliminates environmental pollution and ensures that they get enough oxygen.
Tags: filters made, HEPA filters, particles dust