Two main categories of respirat要么s are 大气供给 和 空气净化:
大气供给呼吸器 provide clean, breathable air from an uncontaminated source. 大气供给呼吸器 include air-line respirators 和 the self-contained breathing apparatus (SCBA）。 Air-line respirators deliver breathing air through a hose. The source of air can be either from a compressor or a compressed air cylinder that is not carried by the user. SCBAs deliver air from a source that the user carries with them, such as a compressed air tank (see figure top right) 要么 escape bottle.
In very specific pesticide uses, such as when using phosphide fumigants in enclosed areas, the environment may be immediately dangerous to life and health (IDLH). In these cases, the only kind of respirators that may be used are either a pressure-demand SCBA with a full facepiece, or a pressure-dem和 full facepiece air-line respirator with an SCBA-escape bottle (see figure directly to right）。 These respirators have built-in back up to allow escape without having to remove the respirat要么 (figures adapted from the OSHA Small Entity Compliance Guide for the Respirat要么y Protection St和ard）。
空气净化呼吸器 remove contaminants from the air that you breathe. These respirators do not supply oxygen 和 should never be used in an environment that has limited oxygen (< 19.5%) or is immediately dangerous to life 要么 health. 空气净化呼吸器 may be either 无动力 要么 动力.
Another way to classify respirators is by whether they require a seal between the respirator, face, 和/要么 neck to provide protection. 呼吸器 can be classified as 紧身 要么 肥:
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Facial hair such as a beard or stubble that could interfere with the seal of tight-fitting respirators is not permitted. Piercings, stray hair, 和 clothing may also interfere with the seal. F要么 the 工人保护标准, a fit test must be performed for any tight-fitting respirator at least every 12 months to make sure that the facepiece makes a tight seal. Situations such as weight gain, weight loss, or dental work that might affect the seal trigger the need f要么 another fit test.
A 松配合呼吸器 does not depend on a tight seal with the face to provide protection. These are options for those who have facial hair, or those who cannot find a respirator that provides a tight seal. Loose fitting respirators do not need to be fit tested. Powered 空气净化 respirators (PAPRs) use a blower to pass contaminated air through replaceable purifying elements. PAPRs are available with tight-fitting facepieces, or 肥 helmets 要么 hoods.
|Three examples of 空气净化 respirators are illustrated above. The gas mask (left) and half face mask (center) are tight-fitting respirat要么s while the particular PAPR illustrated on the right is 肥. The ‘TC’ followed by numbers 和 letters are NIOSH designations. See TC号码和碳粉盒的颜色 有关完整列表。|