Powered air-purifying respirator

The modularity of PAPRs allows them to be customized for different working environments. Regardless of type, a PAPR consists of: • some kind of headgear (mask or hood), • a powered (motor-driven) fan which forces incoming air into the device, • a filter (or multiple filters) for delivery to the user for breathing, and • a battery or other power source. The mask may be hard and tight-fitting, or flexible and loose-fitting. The former affords a higher level of protection, but is less comfortable. Masks may be reusable or disposable. Some masks allow the full face to be seen by others, aiding in interpersonal communication. ==Filters==

PAPRs may be outfitted with mechanical filters for atmospheres with particulate contamination, with a chemical cartridge for atmospheres with toxic gases or vapors, or both in combination. PAPRs can provide an assigned protection factor between 25 and 1000 depending on the type, as compared to an N95 mask's assigned protection factor of 10. In the United States, HE (high-efficiency) filters are the main class of particulate filter used with PAPRs. These are 99.97% efficient against 0.3 micron particles, the same as a P100 filter. PAPR HE filters used in industry are generally re-used until they are soiled, damaged, or reduce PAPR air flow below specified levels. In healthcare settings involving a live virus, CDC recommends that a practical replacement cycle be implemented. == Regulatory requirements ==

42 CFR 84 42 CFR 84, from 1995 to 2020, copies 30 CFR 11 rules for PAPRs. The following table lists the air flow requirements for NIOSH-approved PAPRs under Part 84.175. Tight-fitting PAPRs may be fit tested with the facepiece unpowered and in negative-pressure (under 29 CFR 1910.134) while loose-fitting PAPR fit test protocols have not been changed from 30 CFR 11. The following table lists the ratings for particulate ratings for Part 84 PAPRs. PAPR100 ratings were added in 2020. PAPR100-N is not designed to filter oil particulates, and the official color-coding for all three respirator types is magenta. A study has demonstrated that users carrying out physical work at intensities 80-85% VO2 max "over-breathe" loose-fitting PAPRs and has recommended an increase of air flow to 400 lpm, an approximately two-fold increase over NIOSH-approved values. == Usage ==

, and, since it is being used against asbestos, exhalation valves (white). The hose connects to a PAPR filter-pump. According to the NIOSH Respirator Selection Logic, PAPRs are recommended for concentrations of hazardous particulates or gases that are greater than the relevant occupational exposure limit but less than the immediately dangerous to life or health (IDLH) level and the manufacturer's maximum-use concentration, subject to the respirator having a sufficient assigned protection factor. For substances hazardous to the eyes, a respirator equipped with a full facepiece, helmet, or hood is recommended. PAPRs are not effective during firefighting, in an oxygen-deficient atmosphere, or in an unknown atmosphere; in these situations a self-contained breathing apparatus or supplied-air respirator is recommended instead. In healthcare settings, CDC recommends cleaning of all components except the filter after each use; care must be taken to select PAPRs that are not damaged or deteriorate due to cleaning and disinfecting agents. For CBRN defense (CBRN) Some PAPRs have special certification for chemical, biological, radiological, and nuclear contaminants (CBRN). In the United States, they must be certified to resist permeation of chemical warfare agents, which may involve additional protective coverings; that gas or vapor will not pass through the filter before a specified amount of time; and its ability to fit a wide range of facial sizes and shapes. == See also ==