Respirator

For the mechanical device used to assist breathing, see Ventilator. For the mask worn during surgery, see Surgical mask.

White, disposable Standard N95 filtering facepiece respirator

A half-face elastomeric air-purifying respirator. This kind of respirator is reusable, with the filters being replaced periodically.

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 respirators: 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.

Air-purifying respirators range from relatively inexpensive, single-use, disposable face masks sometimes referred to as a filtering facepiece respirator to a more robust reusable model with replaceable cartridges called an elastomeric respirator. Powered air-purifying respirators (PAPR), use a pump or fan to constantly move air through a filter and supply purified air into a mask, helmet or hood.

History

See also: US Respirator Regulation History (like the N95)

Earliest records to 19th century

Plague doctor

The history of protective respiratory equipment can be traced back as far as the first century, when Pliny the Elder (c. 23 AD–79) described using animal bladder skins to protect workers in Roman mines from red lead oxide dust. ^[1] In the 16th century, Leonardo da Vinci suggested that a finely woven cloth dipped in water could protect sailors from a toxic weapon made of powder that he had designed. ^[2]

In 1785, Jean-François Pilâtre de Rozier invented a respirator.

Alexander von Humboldt introduced a primitive respirator in 1799 when he worked as a mining engineer in Prussia. ^[3] Practically all respirators in the early 18th century consisted of a bag placed completely over the head, fastened around the throat with windows through which the wearer could see. Some were rubber, some were made of rubberized fabric, and still others of impregnated fabric, but in most cases a tank of compressed air or a reservoir of air under slight pressure was carried by the wearer to supply the necessary breathing air. In some devices certain means were provided for the adsorption of carbon dioxide in exhaled air and the rebreathing of the same air many times; in other cases valves allowed exhalation of used air.^{[ citation needed ]}

Julius Jeffreys first used the word "respirator" as a mask in 1836. ^[4] The mask worked by capturing moisture and warmth in exhaled air in a grid of fine metal wires. Inhaled air then was warmed and moistened as it passed through the same metal grid, providing relief to people with lung diseases. The Respirator became popular, and was mentioned in the literature of the day, including in the writings of Elizabeth Gaskell, William Makepeace Thackeray and Charles Dickens.

Woodcut of Stenhouse's mask

"How a Man may Breathe Safely in a Poisonous Atmosphere", an apparatus providing oxygen while using caustic soda to absorb carbon dioxide, 1909

In 1848, the first US patent for an air-purifying respirator was granted to Lewis P. Haslett ^[5] for his 'Haslett's Lung Protector,' which filtered dust from the air using one-way clapper valves and a filter made of moistened wool or a similar porous substance. ^[6] Following Haslett, a long string of patents were issued for air purifying devices, including patents for the use of cotton fibers as a filtering medium, for charcoal and lime absorption of poisonous vapors, and for improvements on the eyepiece and eyepiece assembly.^{[ citation needed ]} Hutson Hurd patented a cup-shaped mask in 1879 which became widespread in industrial use, and Hurd's H.S. Cover Company was still in business in the 1970s. ^[7]

Inventors in Europe included John Stenhouse, a Scottish chemist, who investigated the power of charcoal in its various forms, to capture and hold large volumes of gas. He built one of the first respirators able to remove toxic gases from the air, paving the way for activated charcoal to become the most widely used filter for respirators. ^[8] Irish physicist John Tyndall took Stenhouse's mask, added a filter of cotton wool saturated with lime, glycerin, and charcoal, and in 1871 invented a 'fireman's respirator', a hood that filtered smoke and gas from air, which he exhibited at a meeting of the Royal Society in London in 1874. ^[9] Also in 1874, Samuel Barton patented a device that 'permitted respiration in places where the atmosphere is charged with noxious gases, or vapors, smoke, or other impurities.' ^{[10] [11]} German Bernhard Loeb patented several inventions to 'purify foul or vitiated air,' and counted the Brooklyn Fire Department among his customers.^{[ citation needed ]}

In the late 19th century, Miles Philips began using a "mundebinde" ("mouth bandage") of sterilized cloth which he refined by adapting a chloroform mask with two layers of cotton mull. ^[12] Paul Berger, a Paris surgeon, likewise investigated the protective effect of masks during surgery.

A predecessor of the filtering facepiece respirator was a design by Doctor Lien-teh Wu who was working for the Chinese Imperial Court in the fall of 1910, which was the first that protected users from bacteria in empirical testing. Subsequent respirators were reusable but bulky and uncomfortable. In the 1970s, the Bureau of Mines and NIOSH developed standards for single-use respirators, and the first disposable respirator was developed by 3M and approved in 1972. ^[13]

World War I

The first recorded response and defense against chemical attacks using respirators occurred during the Second Battle of Ypres on the Western Front in World War I. It was the first time Germany used chemical weapons on a large scale releasing 168 tons of chlorine gas over a four-mile (6 km) front killing around 6,000 troops within ten minutes through asphyxiation. The gas being denser than air flowed downwards forcing troops to climb out of their trenches. Reserve Canadian troops, who were away from the attack, used urine-soaked cloths as primitive respirators. A Canadian soldier realized that the ammonia in urine would react with the chlorine, neutralizing it, and that the water would dissolve the chlorine, allowing soldiers to breathe through the gas.^{[ citation needed ]}

20th century

In the 1970s, the successor to the United States Bureau of Mines and NIOSH developed standards for single-use respirators, and the first single-use respirator was developed by 3M and approved in 1972. ^[14] 3M used a melt blowing process that it had developed decades prior and used in products such as ready-made ribbon bows and bra cups; its use in a wide array of products had been pioneered by designer Sara Little Turnbull. ^[15]

21st century

China normally makes 10 million masks per day, about half of the world production. During the COVID-19 pandemic, 2,500 factories were converted to produce 116 million daily. ^[16]

During the COVID-19 pandemic, people in the United States, and in a lot of countries in the world, were urged to make their own cloth masks due to the widespread shortage of commercial masks. ^[17]

Summary of Facepiece Types

Types of respirators by physical form. Click to enlarge.

All respirators have some type of facepiece held to the wearer's head with straps, a cloth harness, or some other method. Facepieces come in many different styles and sizes to accommodate all types of face shapes.

Respirators can have half-face forms that cover the bottom half of the face including the nose and mouth, and full-face forms that cover the entire face. Half-face respirators are only effective in environments where the contaminants are not toxic to the eyes or facial area.

An escape respirator may have no component that would normally be described as a mask, and may use a bite-grip mouthpiece and nose clip instead.

For hazardous environments, like confined spaces, atmosphere-supplying respirators, like SCBAs, should be used.

Use

A wide range of industries use respirators including healthcare & pharmaceuticals, defense & public safety services (defense, firefighting & law enforcement), oil and gas industries, manufacturing (automotive, chemical, metal fabrication, food and beverage, wood working, paper and pulp), mining, construction, agriculture and forestry, cement production, power generation, painting, shipbuilding, and the textile industry. ^[18]

Respirators require user training in order to provide proper protection.

User seal check

Multiple people doing positive pressure user seal checks.

Each time a wearer dons a respirator, they must perform a seal check to be sure that they have an airtight seal to the face so that air does not leak around the edges of the respirator. (PAPR respirators may not require this because they don't necessarily seal to the face.) This check is different than the periodic fit test that is performed by specially trained personnel using testing equipment. Filtering facepiece respirators are typically checked by cupping the hands over the facepiece while exhaling (positive pressure check) or inhaling (negative pressure check) and observing any air leakage around the facepiece. Elastomeric respirators are checked in a similar manner, except the wearer blocks the airways through the inlet valves (negative pressure check) or exhalation valves (positive pressure check) while observing the flexing of the respirator or air leakage. Manufacturers have different methods for performing seal checks and wearers should consult the specific instructions for the model of respirator they are wearing. Some models of respirators or filter cartridges have special buttons or other mechanisms built into them to facilitate seal checks. ^[19]

Fit testing

Main article: Respirator fit test

Most types of respirators depend upon forming a good seal between the respirator body and the face of the wearer. Fit testing procedures have been developed to ensure that the respirator is appropriate for the wearer and the wearer's donning technique is capable of creating an adequate seal. ^[20]

Qualitative fit testing typically subjects the wearer to an atmosphere containing an aerosol that can be detected by the wearer, such as saccharin or isoamyl acetate, with the wearer reporting whether detectable levels of the aerosol has penetrated into the breathing area. Quantitative fit testing typically uses a specially prepared respirator with an inserted probe. The respirator is donned, and aerosol concentrations inside and outside of the mask are compared and used to determine a numerical fit factor. ^[21]

Contrast with surgical mask

An infographic on the difference between surgical masks and N95 respirators

A surgical mask is a loose-fitting, disposable device that creates a physical barrier between the mouth and nose of the wearer and potential contaminants in the immediate environment. If worn properly, a surgical mask is meant to help block large-particle droplets, splashes, sprays, or splatter that may contain viruses and bacteria. Surgical masks may also help reduce exposure from the wearer's saliva and respiratory secretions to others, especially during surgical procedures. ^[22]

A surgical mask, by design, does not filter or block very small particles from the outside air that may be transmitted by coughs, sneezes, or certain medical procedures to the wearer. Surgical masks also do not provide complete protection from germs and other contaminants because of the loose fit between the surface of the face mask and the face. ^[22]

Collection efficiency of surgical mask filters can range from less than 10% to nearly 90% for different manufacturers' masks when measured using the test parameters for NIOSH certification. However, a study found that even for surgical masks with "good" filters, 80–100% of subjects failed an OSHA-accepted qualitative fit test, and a quantitative test showed 12–25% leakage. ^[23]

The U.S. Centers for Disease Control and Prevention (CDC) recommends surgical masks in procedures where there can be an aerosol generation from the wearer, if small aerosols can produce a disease to the patient. ^[24]

Surgical N95

Main article: N95 respirator

A 3M 1860 surgical N95, with a non-surgical 3M 8210 in the background

Some N95 respirators have also been cleared by the U.S. National Institute for Occupational Safety and Health (NIOSH) and U.S. Food and Drug Administration as surgical and are labeled "surgical N95", "medical respirators," or "healthcare respirators". These protect the patient and others from the wearer's respiratory emissions (as a surgical mask would) as well as protect the wearer from airborne particulates and aerosols (as a standard N95 respirator). Unlike a standard N95 respirator, FDA-cleared "healthcare respirators" also provide protection from high-pressure streams or jets of bodily fluid, such as blood. ^{[25] [26]}

The CDC recommends the use of respirators with at least N95 certification to protect the wearer from inhalation of infectious particles including Mycobacterium tuberculosis , avian influenza, severe acute respiratory syndrome (SARS), pandemic influenza, and Ebola. ^[27]

Respirator Selection

Air-purifying respirators are respirators that draw in the surrounding air and purify it before it is breathed (unlike air-supplying respirators, which are sealed systems, with no air intake, like those used underwater). Air-purifying respirators filter particulates, gases, and vapors from the air, and may be negative-pressure respirators driven by the wearer's inhalation and exhalation, or positive-pressure units such as powered air-purifying respirators (PAPRs).

According to the NIOSH Respirator Selection Logic, air-purifying respirators 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 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. Air-purifying respirators are not effective during firefighting, in oxygen-deficient atmosphere, or in an unknown atmosphere; in these situations a self-contained breathing apparatus is recommended instead. ^[28]

Types of Filtration

Mechanical Filter

Main Article: Mechanical filter respirator (and regulatory ratings)

A video describing N95 certification testing

Mechanical filters remove contaminants from air in several ways: interception when particles following a line of flow in the airstream come within one radius of a fiber and adhere to it; impaction, when larger particles unable to follow the curving contours of the airstream are forced to embed in one of the fibers directly; this increases with diminishing fiber separation and higher air flow velocity; by diffusion, where gas molecules collide with the smallest particles, especially those below 100 nm in diameter, which are thereby impeded and delayed in their path through the filter, increasing the probability that particles will be stopped by either of the previous two mechanisms; and by using an electrostatic charge that attracts and holds particles on the filter surface.

There are many different filtration standards that vary by jurisdiction. In the United States, the National Institute for Occupational Safety and Health defines the categories of particulate filters according to their NIOSH air filtration rating. The most common of these are the N95 respirator, which filters at least 95% of airborne particles but is not resistant to oil.

Other categories filter 99% or 99.97% of particles, or have varying degrees of resistance to oil. ^[29]

In the European Union, European standard EN 143 defines the 'P' classes of particle filters that can be attached to a face mask, while European standard EN 149 defines classes of "filtering half masks" or "filtering facepieces", usually called FFP masks. ^[30]

According to 3M, the filtering media in respirators made according to the following standards are similar to U.S. N95 or European FFP2 respirators, however, the construction of the respirators themselves, such as providing a proper seal to the face, varies considerably. (For example, US NIOSH-approved respirators never include earloops because they don't provide enough support to establish a reliable, airtight seal.) Those standards include the Chinese KN95, Australian / New Zealand P2, Korean 1st Class also referred to as KF94, and Japanese DS. ^[31]

Chemical cartridge

Combined gas and particulate respirator filter, type BKF (БКФ), for protection against acid gases. It has a transparent body and a special sorbent that changes color upon saturation. This color change may be used for timely replacement of respirators' filters (like an end-of-service-life indicator, ESLI).

Main article: Respirator cartridge

Chemical cartridge respirators use a cartridge to remove gases, volatile organic compounds (VOCs), and other vapors from breathing air by adsorption, absorption, or chemisorption. A typical organic vapor respirator cartridge is a metal or plastic case containing from 25 to 40 grams of sorption media such as activated charcoal or certain resins. The service life of the cartridge varies based, among other variables, on the carbon weight and molecular weight of the vapor and the cartridge media, the concentration of vapor in the atmosphere, the relative humidity of the atmosphere, and the breathing rate of the respirator wearer. When filter cartridges become saturated or particulate accumulation within them begins to restrict air flow, they must be changed. ^[32]

If the concentration of harmful gases is immediately dangerous to life or health, in workplaces covered by the Occupational Safety and Health Act the US Occupational Safety and Health Administration specifies the use of air-supplied respirators except when intended solely for escape during emergencies. ^[33] NIOSH also discourages their use under such conditions. ^[34]

Air-Purifying Respirators

Filtering facepiece

Filtering facepiece half mask with exhalation valve (class: FFP3)

Filtering facepiece respirators are discarded when they become unsuitable for further use due to considerations of hygiene, excessive resistance, or physical damage. ^[35] These are typically simple, light, single-piece, half-face masks and employ the first three mechanical filter mechanisms in the list above to remove particulates from the air stream. The most common of these is the white, disposable Standard N95 variety; another type is the Surgical N95 mask. It is discarded after single use or some extended period depending on the contaminant.

NIOSH recommends not reusing filtering facepieces in biosafety level 2 or 3 laboratories. ^[36]

Elastomeric

New York Police Department officer wearing a 3M elastomeric respirator with P100-standard particulate filters in the aftermath of the 2007 New York City steam explosion

Main article: Elastomeric respirator

Elastomeric respirators are reusable because of rubber/plastic construction, but the filter cartridges are discarded and replaced when they become unsuitable for further use. ^[35] Typically one or two cartridges attach securely to a mask which has built into it a corresponding number of valves for inhalation and one for exhalation.

Powered air-purifying respirators

Main article: Powered air-purifying respirator

Powered air-purifying respirators (PAPRs) have a battery-powered blower that moves the airflow through the filters. ^[35] They consist of a powered fan which forces incoming air through one or more filters to the user for breathing.

Escape Respirators

A simple Dräger escape respirator. This model has no hood, and instead comes with noseclips to ensure the wearer breathes only through the filter.

See also: Smoke hood

Escape respirators or smoke hoods such as Air-Purifying Escape Respirators are for use by the general public for chemical, biological, radiological, and nuclear (CBRN) terrorism incidents.^{[ citation needed ]} The American National Standards Institute (ANSI) and the International Safety Equipment Association (ISEA) established the American National Standard for Air-Purifying Respiratory Protective Smoke Escape Devices to define both test criteria and approval methods for fire/smoke escape hoods. ANSI/ISEA Standard 110 provides design guidance to manufacturers of Respiratory Protective Smoke Escape Devices (RPED) in the form of performance requirements and testing procedures. ^[37]

Atmosphere-Supplying respirators

These respirators do not purify the ambient air, but supply breathing gas from another source. The three types are the self contained breathing apparatus, in which a compressed air cylinder is worn by the wearer; the supplied air respirators, where a hose supplies air from a stationary source; and combination respirators that integrate both types. ^[38]

Self-contained breathing apparatus

Main article: Self-contained breathing apparatus

A self-contained breathing apparatus (SCBA) typically has three main components: a high-pressure air cylinder (e.g., 2200 psi to 4500 psi), a pressure gauge and regulator, and an inhalation connection (mouthpiece, mouth mask or full face mask), connected together and mounted to a carrying frame or a harness with adjustable shoulder straps and belt so it can be worn on the back.

Open-circuit industrial breathing sets are filled with filtered, compressed air. The compressed air passes through a regulator, is inhaled and exhaled out of the circuit, quickly depleting the supply of air.

Closed-circuit type SCBA filters, supplements, and recirculates exhaled gas like a rebreather. It is used when a longer-duration supply of breathing gas is needed, such as in mine rescue and in long tunnels, and going through passages too narrow for a large open-circuit air cylinder.^{[ citation needed ]}

Supplied air respirator

Main article: Supplied-air respirator

Supplied air respirators make use of a hose to deliver air from a stationary source. It provides clean air for long periods of time and are light weight for the user, although it limits user mobility. They are normally used when there are extended work periods required in atmospheres that are not immediately dangerous to life and health (IDLH). ^[38]

Disadvantages

Hierarchy of Controls Point of View

Further information: Hierarchy of hazard controls

Placing an overemphasis on respirator usage can neglect other, more effective ways of remedying risk.

The Hierarchy of Controls, noted as part of the Prevention Through Design initiative started by NIOSH with other standards bodies, is a set of guidelines emphasizing building in safety during design, as opposed to ad-hoc solutions like PPE, with multiple entities providing guidelines on how to implement safety during development, ^[39] outside of NIOSH-approved respirators. US Government entities currently and formerly involved in the regulation of respirators follow the Hierarchy of Controls, including OSHA ^[40] and MSHA. ^[41]

However, some HOC implementations, notably MSHA's, have been criticized for allowing mining operators to skirt engineering control noncompliance by requiring miners to wear respirators instead if the permissible exposure limit (PEL) is exceeded, without work stoppages, breaking the hierarchy of engineering controls. Another concern was fraud related to the inability to scrutinize engineering controls, ^{[42] [43]} unlike NIOSH-approved respirators, like the N95, which can be fit tested by anyone, are subject to the scrutiny of NIOSH, and are trademarked and protected under US federal law. ^[44]

Respirator Non-Compliance

With regards to people complying with requirements to wear respirators, various papers note high respirator non-compliance across industries, ^{[45] [46]} with a survey noting non-compliance was due in large part due to discomfort from temperature increases along the face, and a large amount of respondents also noting the social unacceptability of provided N95 respirators during the survey. ^[47] For reasons like mishandling, ill-fitting respirators and lack of training, the Hierarchy of Controls dictates respirators be evaluated last while other controls exist and are working. Alternative controls like hazard elimination, administrative controls, and engineering controls like ventilation are less likely to fail due to user discomfort or error. ^{[48] [49]}

A U.S. Department of Labor study ^[50] showed that in almost 40 thousand American enterprises, the requirements for the correct use of respirators are not always met. Experts note that in practice it is difficult to achieve elimination of occupational morbidity with the help of respirators:

It is well known how ineffective ... trying to compensate the harmful workplace conditions with ... the use of respirators by employees. ^[51] Unfortunately, the only certain way of reducing the exceedance fraction to zero is to ensure that Co (note: Co - concentration of pollutants in the breathing zone) never exceeds the PEL value. ^[52]

Counterfeiting, Modification, and Revocation of Regulated Respirators

A counterfeit N95 respirator with no TC#

Another disadvantage of respirators is that the onus is on the respirator user to determine if their respirator is counterfeit or has had its certification revoked. ^[44] Customers and employers can inadvertently purchase non-OEM parts for a NIOSH-approved respirator which void the NIOSH approval and violate OSHA laws, in addition to potentially compromising the fit of the respirator. ^[53] This is another example of respirator mishandling under the Hierarchy of Controls.

Issues with Fit Testing

If respirators must be used, under 29 CFR 1910.134, OSHA requires respirator users to conduct a respirator fit test, with a safety factor of 10 to offset lower fit during real world use. ^[40] However, NIOSH notes the large amount of time required for fit testing has been a point of contention for employers. ^[54]

Other opinions concern the change in performance of respirators in use compared to when fit testing, and compared to engineering control alternatives:

The very limited field tests of air-purifying respirator performance in the workplace show that respirators may perform far less well under actual use conditions than is indicated by laboratory fit factors. We are not yet able to predict the level of protection accurately; it will vary from person to person, and it may also vary from one use to the next for the same individual. In contrast, we can predict the effectiveness of engineering controls, and we can monitor their performance with commercially available state-of-the-art devices. ^[55]

Issues with Respirator Design

Extended use of certain negative-pressure respirators can result in higher levels of carbon dioxide due to dead space and breathing resistance (pressure drop) which can impact functioning and sometimes can exceed the PEL. ^{[56] [57] [58]} This effect was significantly reduced with powered air purifying respirators. ^[59] Certain respirator designs, especially those with head straps, can also lead to headaches, ^[60] dermatitis and acne. ^[61]

Complaints have been leveled at early LANL NIOSH fit test panels (which included primarily military personnel) as being unrepresentative of the broader American populace. ^[62] However, later fit test panels, based on a NIOSH facial survey conducted in 2003, were able to reach 95% representation of working US population surveyed. ^[63] Despite these developments, 42 CFR 84, the US regulation NIOSH follows for respirator approval, allows for respirators that don't follow the NIOSH fit test panel provided that: more than one facepiece size is provided, and no chemical cartridges are made available. ^[64]

Issues with Lack of Regulation

Respirators designed to non-US standards may not be subject to as much or any scrutiny:

• In China, under GB2626-2019, which includes standards like KN95, there is no procedure for fit testing. ^[65]

Some jurisdictions allow for respirator filtration ratings lower than 95%, respirators which are not rated to prevent respiratory infection, asbestos, or other dangerous occupational hazards. These respirators are sometimes known as dust masks for their almost exclusive approval only against dust nuisances:

• In Europe, regulation allows for dust masks under FFP1, where 20% inward leakage is allowed, with a minimum filtration efficiency of 80%. ^[66]
• South Korea allows 20% filter leakage under KF80.

In the US, NIOSH noted that under standards predating the N95, 'Dust/Mist' rated respirators could not prevent the spread of TB. ^[67]

Regulation

The choice and use of respirators in developed countries is regulated by national legislation. To ensure that employers choose respirators correctly, and perform high-quality respiratory protection programs, various guides and textbooks have been developed:

Textbooks and guidelines for the selection and use of respirators
Country	Language	Year of publication	Pages	Institution (hyperlink to document)
US	English	1987	305	NIOSH ( [68] )
US	English	2005	32	NIOSH ( [69] )
US	English	1999	120	NIOSH ( [70] )
US	English	2017	48	Pesticide Educational Resources Collaborative (PERC) ( [71] )
US	English & Spanish	-	-	OSHA ( [72] )
US	English	2011	124	OSHA ( [73] )
US	English	2015	96	OSHA ( [74] )
US	English	2012	44	OSHA ( [75] )
US	English	2014	44	OSHA ( [76] )
US	English	2016	32	OSHA ( [77] )
US	English	2014	38	OSHA ( [78] )
US	English	2017	51	OSHA ( [79] )
US	English	2001	166	NRC ( [80] )
US	English	1986	173	NIOSH & EPA ( [81] )
Canada	French	2013, 2002	60	Institut de recherche Robert-Sauve en santé et en sécurité du travail (IRSST) ( [82] )
Canada	English	2015	-	Institut de recherche Robert-Sauve en sante et en securite du travai (IRSST) ( [83] )
Canada	French	2015	-	Institut de recherche Robert-Sauve en sante et en securite du travai (IRSST) ( [84] )
France	French	2017	68	Institut National de Recherche et de Sécurité (INRS) ( [85] )
Germany	German	2011	174	Spitzenverband der gewerblichen Berufsgenossenschaften und der Unfallversicherungsträger der öffentlichen Hand (DGUV) ( [86] )
UK	English	2013	59	The Health and Safety Executive (HSE) ( [87] )
UK	English	2016	29	The UK Nuclear Industry Good PracIndustry Radiological Protection Coordination Group (IRPCG) ( [88] )
Ireland	English	2010	19	The Health and Safety Authority (HSA) ( [89] )
New Zealand	English	1999	51	Occupational Safety and Health Service (OSHS) ( [90] )
Chile	Spanish	2009	40	Instituto de Salud Publica de Chile (ISPCH) ( [91] )
Spain	Spanish	-	16	Instituto Nacional de Seguridad, Salud y Bienestar en el Trabajo (INSHT) ( [92] )

For standard filter classes used in respirators, see Mechanical filter (respirator)#Filtration standards.

See also

• Cartridge (respirator)  – Container that cleans pollution from air inhaled through itPages displaying short descriptions of redirect targets
• Dust mask  – Pad held over the nose and mouth to protect against dust
• Face shield  – Device used to protect the wearer's face from hazards
• Gas mask  – Protection from inhaling airborne pollutants and toxic gases
• Open-source hardware  – Hardware from the open-design movement
• Microparticle performance rating  – used to measure an air filter's ability to capture small particlesPages displaying wikidata descriptions as a fallback
• Minimum efficiency reporting value  – Measurement scale for the effectiveness of air filters
• Personal protective equipment  – Equipment designed to help protect an individual from hazards (PPE)
• Pocket mask  – Device used to safely deliver first aid rescue breaths
• Self-contained breathing apparatus  – Breathing gas supply system carried by the user
• Smoke hood  – Device to protect the user from smoke inhalation in an emergency
• Surgical mask  – Mouth and nose cover against bacterial aerosols
• Ventilator  – Device that provides mechanical ventilation to the lungs
• Workplace respirator testing  – Testing of respirators in real life conditions

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Further reading

• Savage, Robert C. Woosnam; Hall, Anthony (2002). Brassey's Book of Body Armor . Brassey's. ISBN   978-1-57488-465-4.
• Palazzo, Albert (2000). Seeking Victory on the Western Front: The British Army and Chemical Warfare in World War I . University of Nebraska Press. ISBN   978-0-8032-8774-7.
• Cheremisinoff, Nicholas (1999). Handbook of Industrial Toxicology and Hazardous Materials. Marcel Dekker. ISBN   978-0-8247-1935-7.
• NIOSH respirators main page
• NIOSH respirator fact sheet
• What's Special about Chemical, Biological, Radiological, and Nuclear (CBRN) Air-Purifying Respirators (APR)? NIOSH Fact Sheet
• NIOSH-Approved Disposable Particulate Respirators (Filtering Facepieces)
• TSI Application note ITI-041: Mechanisms of Filtration for High Efficiency Fibrous Filters Archived 29 August 2017 at the Wayback Machine
• British Standard BS EN 143:2000: Respiratory protective devices – Particle filters – Requirements, testing, marking
• British Standard BS EN 149:2001: Respiratory protective devices – Filtering half masks to protect against particles – Requirements, testing, marking

External links

• 3M Safety Respirator Classification Guide 3M.com
• Mine Safety Appliance Company (MSA) Respirator Classification Guide MSA.com
• CDC Protective Masks Fact Sheet cdc.gov/niosh
• Canadian Centre for Occupational Health and Safety (CCOHS) Respirator Selection ccohs.ca
• The following links are respirator selection logic and competitive bid research information pages for Chemical, Biological, Radiological, and Nuclear (CBRN) defense responders:

• Air-Purifying Respirators (APR): cdc.gov/niosh. Respirator manufacturer approvals for NIOSH-certified air-purifying respirator with CBRN Protections (CBRN APR). This link covers APR and Air-Purifying Escape Respirators (APER) certified by the NIOSH's National Personal Protective Technology Laboratory (NPPTL), Pittsburgh, PA, to CBRN protection NIOSH standards. CBRN APR are tight-fitting, full-face respirators with approved accessories and protect the user breathing zone by relying on user negative pressure, fit testing and user seal checks to filter less than Immediately Dangerous to Life and Health (IDLH) concentrations of hazardous respiratory compounds and particulates through NIOSH CBRN Cap 1, Cap 2 or Cap 3 canisters for CBRN APR- or CBRN 15- or CBRN 30-rated APER.
• PAPR: cdc.gov/niosh. Respirator manufacturer approvals for NIOSH-certified powered air-purifying respirator with CBRN Protections (CBRN PAPR-loose fitting or tight fitting)

• OSHA videos on respiratory protection Archived 4 February 2012 at the Wayback Machine osha.gov
• Occupational Safety & Health Administration, Respiratory Protection Training Video on respiratory protection
• The Invention of the Gas Mask brinkster.com