Figure 2-11 Air purifying respirator.
service indicator, they may not be used for contaminants that have poor odor warning
properties. The maximum concentration for which the air-purifying unit is effective is
specified by applicable Federal occupational health standards. Respirators will not
provide the maximum design protection specified unless the face piece is carefully fitted
to the wearer's face to prevent inward leakage. Fit testing is a requirement of Federal
Law and Army regulation. The time period over which protection is provided is
dependent on canister, cartridge, or filter type, concentration and physical state of
contaminant, and the wearer's respiratory rate. The proper type of canister, cartridge,
or filter must be selected for the particular atmosphere and condition. Air purifying
respirators may cause discomfort and objectionable resistance to breathing. Respirator
face pieces present special problems to individuals required to wear prescription lenses,
and those individuals who have a profile on shaving. Army Regulation 11-34, The Army
Respiratory Protection Program specifically prohibits unshaven personnel (especially
having beards) from working in environments where wearing a respirator is required.
This requirement is also an OSHA mandate.
c. Gas and Vapor-Removing Respirators.
(1) General description . See Figure 2-12. Packed solvent beds (cartridge or canister)
remove single gases or vapors (for example, chlorine gas), a single class of gases or vapors (for
example, organic vapors) or a combination of two or more classes of gases and vapors
(for example, acid gases, organic vapors, ammonia, and carbon monoxide) by
absorption, chemical reaction or catalysis or a combination of these methods.