A powered air-purifying respirator (PAPR) is a type of respirator used to safeguard workers against contaminated air. PAPRs consist of a headgear-and-fan assembly that takes ambient air contaminated with one or more type of pollutant or pathogen, actively removes (filters) a sufficient proportion of these hazards, and then delivers the clean air to the user's face or mouth and nose. They have a higher assigned protection factor than filtering facepiece respirators such as N95 masks. PAPRs are sometimes called positive-pressure masks, blower units, or just blowers.
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. Tight-fitting PAPRs require a fit test, while loose-fitting ones do not. This makes loose-fitting PAPRs useful when a fit test for a tight-fitting respirator cannot be successfully passed, for example when facial hair is present. Masks may be reusable or disposable. Some masks allow the full face to be seen by others, aiding in interpersonal communication.
The fan, filter, and power-pack may be carried around freely by the user, often secured by a belt around the waist. Alternatively, with certain units, the air is fed to the user via lengthy tubing while the fans and filters are remotely mounted.
PAPRs have low breathing resistance, unlike filtering facepiece respirators such as N95 masks. A PAPR may have adjustable air flow rates for added comfort. While they are often referred to as positive pressure masks, they are not true positive-pressure devices as overbreathing can overcome the pressure supplied by the fan.
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A respirator fit test checks whether a respirator properly fits the face of someone who wears it. The fitting characteristic of a respirator is the ability of the mask to separate a worker's respiratory system from ambient air. This is achieved by tightly pressing the mask flush against the face (without gaps) to ensure an efficient seal on the mask perimeter. Because wearers cannot be protected if there are gaps, it is necessary to test the fit before entering into contaminated air. Multiple forms of the test exist.
droite|vignette|200x200px| Masque N95 Le masque N95 est un masque de protection anti-particules avec un filtre, répondant à la classification de filtration de l'air de l'agence américaine NIOSH (National Institute for Occupational Safety and Health). Il filtre au moins 95 % des particules en suspension dans l'air mais n'est pas résistant à l'huile et ne filtre ni les gaz ni les vapeurs, tout comme le FFP2, son équivalent européen (qui filtre au moins 94 % des particules) ou le masque KN95 de Chine.
The respiratory protective devices (RPD) can protect workers only if their protective properties are adequate to the conditions in the workplace. Therefore, specialists have developed criteria for the selection of proper, adequate respirators, including the Assigned Protection Factors (APF) - the decrease of the concentration of harmful substances in the inhaled air, which (is expected) to be provided with timely and proper use of a certified respirator of certain types (design) by taught and trained workers (after individual selection with a tight-fitting mask and fit testing), when the employer performs an effective respiratory protective device programme.
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