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Types of Gas Masks

Gas masks, first developed in the late 19th century, have been refined over the decades and serve to protect humans from inhaling contaminated air. These contaminants can include dust, biological pathogens, chemicals and dangerous vapors. Great strides have been made in creating specialized masks that can save lives in a variety of hazardous situations. Firefighters, soldiers, nuclear plant workers and anyone else working in hazardous conditions are likely to have one kind of mask or another.

  1. Air-Purifying Masks

    • These are the most common types of gas masks. They are the ones available in stores for civilian use in case of an emergency or chemical attack. They work by removing contaminants in the air using filters. There are usually two filters, one on each side of the mask, but some exist with only one large filter in the front. The person breathes inside the mask and draws the air through the filters. A major disadvantage is the limited lifetime of the filters. Any breach in the mask-face bond could compromise its function.These masks require sufficient oxygen to be present in the air being filtered.

    Supplied-Air Respirators

    • These masks are superior to air-purifying masks. A battery-operated fan pumps fresh clean air into the mask, creating a positive pressure inside. Thus, a breach in the mask would not lead to the entry of contaminated air. These are more expensive than air-purifying masks and require batteries to function at all. Due to the consistent airflow through the filters into the mask, these filters need frequent changing.

    SCBA

    • Scuba divers are the most recognizable users of such devices. SCBA stands for "Self-Contained Breathing Apparatus," which includes tanks to supply air, regulator hoses to channel the air, and a full face mask. As with supplied-air respirators, the air flowing into the mask creates a positive pressure, protecting the user from leaks. The main disadvantage of SCBA systems is the limited time the tanks can supply air -- usually about 30 minutes. They are also more expensive than supplied-air respirators.

    Vapor-Proof Suit

    • A vapor-proof suit surrounds the entire body of the wearer to protect against radioactive or corrosive elements. It is also used in biological hazard situations to prevent pathogens from entering a person's bloodstream. Such a suit must include a self-contained air supply, which brings with it the advantages and disadvantages of air-supplied respirators and other SCBA systems. This body suit is the ultimate form of protection against atmospheric contamination.

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