Missouri, California Homeland Response Force 130520-Z-UP142-060 crop

A powered air-purifying respirator (PAPR) is a type of

respirator 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 pathogens such as viruses. There are two main categories of respir ...

used to safeguard workers against

contaminated Contamination is the presence of a constituent, impurity, or some other undesirable element that spoils, corrupts, infects, makes unfit, or makes inferior a material, physical body, natural environment, workplace, etc. Types of contamination ...

air. PAPRs consist of a headgear-and-fan assembly that takes ambient

air The atmosphere of Earth is the layer of gases, known collectively as air, retained by Earth's gravity that surrounds the planet and forms its planetary atmosphere. The atmosphere of Earth protects life on Earth by creating pressure allowing f ...

contaminated with one or more type of

pollutant A pollutant or novel entity is a substance or energy introduced into the environment that has undesired effects, or adversely affects the usefulness of a resource. These can be both naturally forming (i.e. minerals or extracted compounds like oi ...

pathogen In biology, a pathogen ( el, πάθος, "suffering", "passion" and , "producer of") in the oldest and broadest sense, is any organism or agent that can produce disease. A pathogen may also be referred to as an infectious agent, or simply a germ ...

, 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 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 filtratio ...

. PAPRs are sometimes called positive-pressure masks, blower units, or just blowers.

Description

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 Filter, filtering or filters may refer to: Science and technology Computing * Filter (higher-order function), in functional programming * Filter (software), a computer program to process a data stream * Filter (video), a software component tha ...

(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 Facial hair is hair grown on the face, usually on the chin, cheeks, and upper lip region. It is typically a secondary sex characteristic of human males. Men typically start developing facial hair in the later stages of puberty or adolescence, ...

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

. A PAPR may have adjustable air flow rates for added comfort. While they are often referred to as

positive pressure Positive pressure is a pressure within a system that is greater than the environment that surrounds that system. Consequently, if there is any leak from the positively pressured system it will egress into the surrounding environment. This is in ...

masks, they are not true positive-pressure devices as overbreathing can overcome the pressure supplied by the fan.

Filters

PAPRs may be outfitted with mechanical filters for atmospheres with

particulate Particulates – also known as atmospheric aerosol particles, atmospheric particulate matter, particulate matter (PM) or suspended particulate matter (SPM) – are microscopic particles of solid or liquid matter suspended in the air. The ter ...

contamination, with a

chemical cartridge A respirator cartridge or canister is a type of filter that removes gases, volatile organic compounds (VOCs), and other vapors from air through adsorption, absorption, or chemisorption. It is one of two basic types of filters used by air-purifyi ...

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 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 filtratio ...

's assigned protection factor of 10. 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 Elastomeric respirators, also called reusable air-purifying respirators, seal to the face with elastomeric material, which may be a natural or synthetic rubber. They are generally reusable. Full-face versions of elastomeric respirators seal bet ...

masks) have an APF of 1000. 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. 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 The micrometre ( international spelling as used by the International Bureau of Weights and Measures; SI symbol: μm) or micrometer (American spelling), also commonly known as a micron, is a unit of length in the International System of Unit ...

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. 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 In classical physics and general chemistry, matter is any substance that has mass and takes up space by having volume. All everyday objects that can be touched are ultimately composed of atoms, which are made up of interacting subatomic partic ...

such as the

dust Dust is made of fine particles of solid matter. On Earth, it generally consists of particles in the atmosphere that come from various sources such as soil lifted by wind (an aeolian process), volcanic eruptions, and pollution. Dust in homes ...

created during various

woodwork Woodworking is the skill of making items from wood, and includes cabinet making (cabinetry and furniture), wood carving, joinery, carpentry, and woodturning. History Along with stone, clay and animal parts, wood was one of the first materials ...

ing processes, or from working with mineral-based materials. When used with

high-efficiency particulate air HEPA (, high-efficiency particulate air) filter, also known as high-efficiency particulate absorbing filter and high-efficiency particulate arrestance filter, is an efficiency standard of air filters. Filters meeting the HEPA standard must sa ...

(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, APRsare suitable for working with volatile

organic compound In chemistry, organic compounds are generally any chemical compounds that contain carbon-hydrogen or carbon-carbon bonds. Due to carbon's ability to catenate (form chains with other carbon atoms), millions of organic compounds are known. The ...

s such as those used in many

spray paint Aerosol paint (commonly spray paint) is paint that comes in a sealed, pressurized container and is released in an aerosol spray when a valve button is depressed. Aerosol painting is one form of spray painting; it leaves a smooth, even coat, unlike ...

s. 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 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 ...

or filter and then use the term respirator to mean a unit that can handle organic

solvent A solvent (s) (from the Latin '' solvō'', "loosen, untie, solve") is a substance that dissolves a solute, resulting in a solution. A solvent is usually a liquid but can also be a solid, a gas, or a supercritical fluid. Water is a solvent for ...

Usage

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 An occupational exposure limit is an upper limit on the acceptable concentration of a hazardous substance in workplace air for a particular material or class of materials. It is typically set by competent national authorities and enforced by legi ...

but less than the

immediately dangerous to life or health 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 advers ...

(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 Firefighting is the act of extinguishing or preventing the spread of unwanted fires from threatening human lives and destroying property and the environment. A person who engages in firefighting is known as a firefighter. Firefighters typically ...

, in an

oxygen-deficient atmosphere Inert gas asphyxiation is a form of asphyxiation which results from breathing a physiologically inert gas in the absence of oxygen, or a low amount of oxygen, rather than atmospheric air (which is composed largely of nitrogen and oxygen). Examples ...

, or in an unknown atmosphere; in these situations a

self-contained breathing apparatus 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 ...

or supplied-air respirator is recommended instead. PAPRs have the advantage of eliminating breathing resistance caused by unpowered negative-pressure respirators such as

. This makes them usable by persons who are medically disqualified from negative-pressure respirators. Loose-fitting PAPRs may also be selected for people who cannot pass a fit test due to facial hair or other reasons. PAPRs have disadvantages in terms of

ergonomic Human factors and ergonomics (commonly referred to as human factors) is the application of psychological and physiological principles to the engineering and design of products, processes, and systems. Four primary goals of human factors learnin ...

impacts, and they restrict

peripheral vision Peripheral vision, or ''indirect vision'', is vision as it occurs outside the point of fixation, i.e. away from the center of gaze or, when viewed at large angles, in (or out of) the "corner of one's eye". The vast majority of the area in the ...

In healthcare

Because they provide higher assigned protection factors, PAPRs are suitable for use during

aerosol-generating procedure An aerosol-generating procedure (AGP) is a medical or health-care procedure that a public health agency such as the World Health Organization or the United States Centers for Disease Control and Prevention (CDC) has designated as creating an increa ...

s and by hospital first receivers. 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. Racal Space Suits

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 disease An infection is the invasion of tissues by pathogens, their multiplication, and the reaction of host tissues to the infectious agent and the toxins they produce. An infectious disease, also known as a transmissible disease or communicable dise ...

For CBRN defense

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. Under

(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.

References