Powered air-purifying respirator

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A powered air-purifying respirator with a belt-pack filter-blower that feeds air to the elastomeric mask. Fil'truiushchii SIZOD s podachei vozdukha dlia ChS.jpg
A powered air-purifying respirator with a belt-pack filter-blower that feeds air to the elastomeric mask.
A PAPR, gown, and biosafety cabinet in use in a BSL-3 laboratory. All parts of the PAPR are visible: the waist unit holding the fan, filter, and battery; the hose; and the mask, in this case a flexible, loose-fitting one. Influenza virus research.jpg
A PAPR, gown, and biosafety cabinet in use in a BSL-3 laboratory. All parts of the PAPR are visible: the waist unit holding the fan, filter, and battery; the hose; and the mask, in this case a flexible, loose-fitting one.
A PAPR with a rigid, tight-fitting mask Missouri, California Homeland Response Force 130520-Z-UP142-060 crop.jpg
A PAPR with a rigid, tight-fitting mask

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: [1]

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. [2] 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. [2] [3] Masks may be reusable or disposable. Some masks allow the full face to be seen by others, aiding in interpersonal communication. [1]

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.[ citation needed ]

PAPRs have low breathing resistance, unlike filtering facepiece respirators such as N95 masks. [3] A PAPR may have adjustable air flow rates for added comfort. [1] 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. [4]


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. [5] 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. [2] [3] Loose-fitting PAPRs typically have an APF of 25, and PAPRs with elastomeric masks that seal to the face (similar to those in elastomeric respirator masks) have an APF of 1000. [6] When comparing various makes and models of PAPR, the supporting documentation from each of the respective manufacturers should be consulted in order to confirm the APF value of each product. [7]

In the United States, HE (high-efficiency) filters are the class of particulate filter used with PAPRs. These are 99.97% efficient against 0.3 micron particles, the same as a P100 filter. [1] [8] [9] 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. [1]

The type of filter incorporated into a PAPR must be appropriate to the contaminants that need to be removed. Some respirators are designed to remove fine particulate matter such as the dust created during various woodworking processes, or from working with mineral-based materials. When used with high-efficiency particulate air (HEPA) filters, airborne particles containing pathogens (viruses, bacteria) smaller than 5 microns will be removed. (PAPRs are typically required for lab workers in BSL-3 facilities, and sometimes in BSL-2 as well.)

When used in combination with the correct filters, [PAPRs] are suitable for working with volatile organic compounds such as those used in many spray paints. At the same time, the filters that are suitable for volatile substances must typically have their filter elements replaced more often than particulate filters. In addition, there is some confusion over terminology. Some literature and users will refer to a particulate filtering unit as a dust mask or filter and then use the term respirator to mean a unit that can handle organic solvents.[ citation needed ]


This full-face mask has an inner orinasal mask to reduce dead space, and, since it is being used against asbestos, exhalation valves (white). The hose connects to a PAPR filter-pump. Asbestos mask.jpg
This full-face mask has an inner orinasal mask to reduce dead space, 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. [5]

PAPRs have the advantage of eliminating breathing resistance caused by unpowered negative-pressure respirators such as N95 masks. This makes them usable by persons who are medically disqualified from negative-pressure respirators. [3] Loose-fitting PAPRs may also be selected for people who cannot pass a fit test due to facial hair or other reasons. [2] [3] PAPRs have disadvantages in terms of ergonomic impacts, and they restrict peripheral vision. [2]

In healthcare

Because they provide higher assigned protection factors, PAPRs are suitable for use during aerosol-generating procedures [1] and by hospital first receivers. [1] [10] 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 [11] . [1]

Racal suits consist of a PAPR combined with a separate protective suit. They are used in healthcare settings, in this case by the U.S. Army Aeromedical Isolation Team at Fort Detrick, Maryland Racal Space Suits.JPG
Racal suits consist of a PAPR combined with a separate protective suit. They are used in healthcare settings, in this case by the U.S. Army Aeromedical Isolation Team at Fort Detrick, Maryland

In healthcare, a product known as the Racal suit can be used, consisting of a plastic suit and a PAPR fitted with HEPA filters. They were used by the U.S. Army Aeromedical Isolation Team to perform medical evacuations of patients with highly infectious diseases. [12] [13]

For CBRN defense

A PAPR certified for chemical, biological, radiological, and nuclear contaminants (CBRN) CBRN powered air-purifying respirator.jpg
A PAPR certified for chemical, biological, radiological, and nuclear contaminants (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. [14]

Under immediately dangerous to life or health (IDLH) conditions, tight‐fitting full facepiece gas mask respirators with canisters (those with "14G approval") with CBRN approval may be used for escape, but loose‐fitting hoods and cartridges (those with "23C approval") with CBRN approval may not. Neither may be used to enter an IDLH atmosphere. The 23C CBRN PAPRs also must not be used if liquid droplet exposure occurs. [14]

See also

Related Research Articles

Gas mask Protection from inhaling airborne pollutants and toxic gases

A gas mask is a mask used to protect the wearer from inhaling airborne pollutants and toxic gases. The mask forms a sealed cover over the nose and mouth, but may also cover the eyes and other vulnerable soft tissues of the face. Most gas masks are also respirators, though the word gas mask is often used to refer to military equipment, the scope used in this article. The gas mask only protects the user from digesting, inhaling and contact through the eyes. Most combined gas mask filters will last around 8 hours in a nuclear biological chemical (NBC) situation. Chemical specific filters can last up to 20 hours in an NBC situation.

Personal protective equipment Equipment designed to help protect an individual from hazards

Personal protective equipment (PPE) is protective clothing, helmets, goggles, or other garments or equipment designed to protect the wearer's body from injury or infection. The hazards addressed by protective equipment include physical, electrical, heat, chemicals, biohazards, and airborne particulate matter. Protective equipment may be worn for job-related occupational safety and health purposes, as well as for sports and other recreational activities. Protective clothing is applied to traditional categories of clothing, and protective gear applies to items such as pads, guards, shields, or masks, and others. PPE suits can be similar in appearance to a cleanroom suit.

Self-contained breathing apparatus Breathing gas supply system carried by the user

A self-contained breathing apparatus (SCBA), sometimes referred to as a compressed air breathing apparatus (CABA) or simply breathing apparatus (BA), is a device worn to provide breathable air in an atmosphere that is immediately dangerous to life or health. They are typically used in firefighting and industry. The term self-contained means that the SCBA is not dependent on a remote supply of breathing gas. If designed for use under water, it is also known as a Scuba set. When not used underwater, they are sometimes called industrial breathing sets. Unofficial names include air pack, air tank, oxygen cylinder or simply pack, which are mostly used in firefighting.

Respirator Device worn to protect the user from inhaling contaminants

A respirator is a device designed to protect the wearer from inhaling hazardous atmospheres, including fumes, vapours, gases and particulate matter such as dusts and airborne microorganisms. There are two main categories: the air-purifying respirator, in which respirable air is obtained by filtering a contaminated atmosphere, and the air-supplied respirator, in which an alternate supply of breathable air is delivered. Within each category, different techniques are employed to reduce or eliminate noxious airborne contaminants.

A breathing mask is a mask that covers the mouth, and usually other parts of the face or head, designed to direct the wearer's breath to and/or from a particular apparatus. It may mean, or be part of, one of these:

Immediately dangerous to life or health Exposure to dangerous levels of airborne contaminants

The term immediately dangerous to life or health (IDLH) is defined by the US National Institute for Occupational Safety and Health (NIOSH) as exposure to airborne contaminants that is "likely to cause death or immediate or delayed permanent adverse health effects or prevent escape from such an environment." Examples include smoke or other poisonous gases at sufficiently high concentrations. It is calculated using the LD50 or LC50. The Occupational Safety and Health Administration (OSHA) regulation defines the term as "an atmosphere that poses an immediate threat to life, would cause irreversible adverse health effects, or would impair an individual's ability to escape from a dangerous atmosphere."

Hazmat suit Protective suit against chemical, bacteriological, and nuclear risks

A hazmat suit is a piece of personal protective equipment that consists of an impermeable whole-body garment worn as protection against hazardous materials. Such suits are often combined with self-contained breathing apparatus (SCBA) to ensure a supply of breathable air. Hazmat suits are used by firefighters, emergency medical technicians, paramedics, researchers, personnel responding to toxic spills, specialists cleaning up contaminated facilities, and workers in toxic environments.

Dust mask Pad held over the nose and mouth to protect against dust

A dust mask is a flexible paper pad held over the nose and mouth by elastic or rubber straps for personal comfort against non-toxic nuisance dusts. They are not intended to provide protection from toxic airborne hazards. The European FFP1 mask, the lowest-grade mechanical filter respirator available in the jurisdiction, is also used as a dust mask.

Orinasal mask Breathing mask that covers the mouth and the nose only.

An orinasal mask, oro-nasal mask or oral-nasal mask is a breathing mask that covers the mouth and the nose only. It may be a complete independent item, as an oxygen mask, or on some anaesthetic apparatuses, or it may be fitted as a component inside a fullface mask on underwater breathing apparatus, a gas mask or an industrial respirator to reduce the amount of dead space. It may be designed for its lower edge to seal on the front of the lower jaw or to go under the chin.

Escape respirator

Escape respirators are a portable breathing apparatus or mask that regenerates breathable air to help provide respiratory protection for emergency escape from areas containing harmful gases or IDLH atmospheres. There are two types of escape respirators: air-purifying escape respirators and self-contained escape respirators. Often times, these respirators utilize an easy-to-put-on hood and some sort of supplied air tank or filter attachment that cleans the incoming air for the user. Escape respirators are not to be used for anything other than escaping a contaminated environment. Escape respirators are not to be used for general or everyday respiratory protection. A cross-breed between a gas mask and a respirator, the escape respirator is used extensively in the mining and chemical industries, and by emergency responders. Escape respirators should be certified by a national authority analogous to the United States' National Institute for Occupational Safety and Health for escaping from the atmosphere in which the respirator is manufactured for.

Respirator fit test

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.

Chemical cartridge container that cleans pollution from air inhaled through it

A respirator cartridge or canister is a type of filter that removes gases, volatile organic compounds (VOCs), and other vapours from breathing air through adsorption, absorption, or chemisorption. It is one of two basic types of filters used by air-purifying respirators.The other is a mechanical filter, which removes only particulates. Hybrid filters combine the two.

The National Personal Protective Technology Laboratory (NPPTL) is a research center within the National Institute for Occupational Safety and Health located in Pittsburgh, Pennsylvania, specifically devoted towards the research of personal protective equipment (PPE). The NPPTL was created in 2001 at the request of the U.S. Congress, in response to a recognized need for improved research in PPE and technologies. It focuses on experimentation and recommendations for respirator masks, by ensuring a level of standard filter efficiency, and develops criteria for testing and developing PPE.

NIOSH air filtration rating U.S. rating of respirators such as face masks

The NIOSH air filtration rating is the U.S. National Institute for Occupational Safety and Health (NIOSH)'s classification of filtering respirators. The ratings describe the ability of the device to protect the wearer from dust and liquid droplets in the air. The certification and approval process for respiratory protective devices is governed by Part 84 of Title 42 of the Code of Federal Regulations. Respiratory protective devices so classified include air-purifying respirators (APR) such as filtering facepiece respirators and chemical protective cartridges that have incorporated particulate filter elements.

Respirator assigned protection factors

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 to be provided with timely and proper use of a certified respirator of certain types (design) by taught and trained workers, when the employer performs an effective respiratory protective device programme.

Workplace respirator testing Testing of respirators in real life conditions

Respirators, also known as respiratory protective equipment (RPE) or respiratory protective devices (RPD), are used in some workplaces to protect workers from air contaminants. Initially, respirator effectiveness was tested in laboratories, but in the late 1960s it was found that these tests gave misleading results regarding the level of protection provided. In the 1970s, workplace-based respirator testing became routine in industrialized countries, leading to a dramatic reduction in the claimed efficacy of many respirator types and new guidelines on how to select the appropriate respirator for a given environment.

N95 respirator Particulate respirator meeting the N95 standard

An N95 filtering facepiece respirator, commonly abbreviated N95 respirator, is a particulate-filtering facepiece respirator that meets the U.S. National Institute for Occupational Safety and Health (NIOSH) N95 classification of air filtration, meaning that it filters at least 95% of airborne particles. This standard does not require that the respirator be resistant to oil; another standard, P95, adds that requirement. The N95 type is the most common particulate-filtering facepiece respirator. It is an example of a mechanical filter respirator, which provides protection against particulates but not against gases or vapors. An authentic N95 respirator is marked with the text "NIOSH" or the NIOSH logo, the filter class ("N95"), a "TC" approval number of the form XXX-XXXX, the approval number must be listed on the NIOSH Certified Equipment List (CEL) or the NIOSH Trusted-Source page, and it must have headbands instead of ear loops.

Mechanical filter (respirator) Air-filtering face masks or mask attachments

Mechanical filters are a class of filter for air-purifying respirators that mechanically stops particulates from reaching the wearer's nose and mouth. They come in multiple physical forms.

Elastomeric respirator Respirator with a rubber face seal

Elastomeric respirators, also called reusable air-purifying respirators, are a type of respirator that seals to the face using a mask made of an elastomeric material, which may be a natural or synthetic rubber. They are generally reusable. Full-face versions of elastomeric respirators seal better and protect the eyes.

Supplied-air respirator

A supplied-air respirator (SAR) or air-line respirator is a device used in places where the air may not be safe. It uses an air hose to supply air from outside the danger zone. It is similar to a self-contained breathing apparatus (SCBA), except that SCBA users carry their air with them in tanks, while SAR users get it from a stationary air supply attached to them by a hose.


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