Elastomeric respirator

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Elastomeric respirator
Police officer wearing half-mask respirator.jpg
Protective P100 half-face elastomeric filter mask worn by a NYPD officer; proprietary 3M pink pancake filters
Similar mask with generic flat disk filters. Paulodj.jpg
Similar mask with generic flat disk filters.

Elastomeric respirators, also called reusable air-purifying respirators, [1] 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 better and protect the eyes. [2]

Contents

Elastomeric respirators consist of a reusable mask that seals to the face, with exchangeable filters. [3] [4] Elastomeric respirators can be used with chemical cartridge filters that remove gases, mechanical filters that retain particulate matter, or both. [5] As particulate filters, they are comparable [3] (or, due to the quality and error-tolerance of the elastomeric seal, possibly superior [5] ) to filtering facepiece respirators such as most disposable N95 respirators and FFP masks. [3]

Elastomeric air-purifying respirators are designed to be safely reused for years. Provided the cartridge integrity and filter have not been compromised, current practice shows that the filters could be used for at least one year. [6] Some, but not all, filter materials are proprietary and manufacturer-specific, [7] and supply-chain failures can make replacements hard to find. [2] [7]

Although powered air-purifying respirators and air-supplying respirators may have elastomeric masks, they are not generally referred to as elastomeric respirators. [3] [4]

Physical form

This full-face mask also protects the eyes, and has an inner orinasal mask to reduce dead space. Pink hard-case P100 particulate filter cartridges make their presence or absence conspicuous at a distance. P100 fullface elastomeric respirator.png
This full-face mask also protects the eyes, and has an inner orinasal mask to reduce dead space. Pink hard-case P100 particulate filter cartridges make their presence or absence conspicuous at a distance.

Elastomeric respirators are examples of air-filtering respirators, in contrast to air-supplying respirators. Air-supplying respirators are usually positive-pressure, so they leak outwards, and thus offer better protection. They are more complex and heavier, but less bulky about the head, and can be worn for longer. [1] Air-purifying respirators draw the surrounding air through filters which remove contaminants. [8]

A range of elastomers are used, including silicone, neoprene, EPDM (ethylene propylene diene monomer rubber), or proprietary elastomers such as Hycar. Latex is rarely used due to allergies. Many manufacturers offer a choice of two materials. [5]

Elastomeric respirators include: [9]

Some elastomeric masks include one-way valves to let exhaled air out unfiltered. This reduces the resistance when the user is breathing out, and some find it makes the mask more comfortable. [2] It may also reduce inwards leakage. [10] However, masks which do not filter exhaled air cannot be used for source control. [2]

Filter types

Elastomeric respirator exploded view (Respirator types snapshot at 1024) (cropped to respirator).png
An exploded view of a respirator, showing two reusable plastic screw-on rings and a disposable disk of N95 particulate filter material.
Elastomeric respirator exploded view (Respirator types snapshot at 1024) (cropped to filter disk).png
Disk of filter material from previous image, with mark showing it is N95-certified circled
Respirator types snapshot1143 P100 filter for elastomeric mask.png
Another type of filter disk. This is a P100 filter, a higher standard than the previous N95 filter.

Air-purifying respirators have filters. The masks and filters come in a variety of standards for mechanical filters and for chemical cartridges, intended for a variety of purposes. [8] An appropriate standard of filter must be used for the mask to be effective. [2]

Filters may be contained in cartridges or canisters; there are also flexible flat and pancake-style filters (see illustrations). [2] Filters are usually mounted on the face, but in the case of powered air-purifying respirators, they are mounted on the belt, and a fan drives air through them and into the face mask. Most masks take one or more filters. [5]

Particulate filters

As of 2020, the commercially available particulate filter disks and cartridges are disposable, and must be replaced when clogged due to accumulated particles (so that breathing resistance is too high), damaged (torn or soiled with something that will damage the filter, such as many fluids; physical or chemical damage), or contaminated (the outside has caught dangerous particulates; for instance, infectious particles). [2] Disinfection and reuse techniques have been tested for emergency use; some, like soap and water, destroy traditional disposable electret filters by removing the electret charge. Launderable, reusable electret filters were being developed during the COVID-19 pandemic. [10]

Particulate filters may be simple disks or other shapes of flat filter material, [11] which are lightweight, [12] or they may be pancake-style [2] hollow discs with a smaller central plastic connecting tube on one side. [13] Particulate filters may also be enclosed in hard-cased disposable cartridges. The disposable cases protect the filter against splashes and can be wiped clean, which may be important in some applications. [14] [2]

In the 2020 COVID-19 pandemic, plastic adapters and filter-holders were 3D-printed in large quantities. These fit on common masks originally made to take proprietary filters (the type shown below). The adapters hold circles cut out of surgical masks, utilizing them as filter discs (as shown above). Six filter discs can be cut from one mask. [15]

Like other proprietary refills, proprietary filter cartridges cause vendor lock-in.

Chemical cartridges

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A protester in Venezuela wearing a gas mask, an elastomeric respirator with chemical cartridges.
Atemluftfilter herstellerspezifisch.jpg
The manufacturer-specific cartridge filter. Colour-coding suggests that this brown-banded cartridge is a different standard from the yellow-banded cartridges the protestor is using.

Different types of cartridge must be used to filter out different chemicals. Most cartridges are made of activated charcoal, which has a very high surface area to adsorb toxins onto. These carbon filters are often impregnated with reagents which react and bond with the specific airborne chemical(s) the cartridge targets. This process is called chemisorption; the reagents bond the toxic gases and vapors before the wearer can breathe them in. The activated carbon may be saturated with copper, zinc, silver and molybdenum compounds, as well as with triethylenediamine (TEDA) [16] [17] Many chemicals cannot be safely filtered out by any chemical cartridge. [18]

Chemical cartridges must generally be kept sealed from the air until use, and will eventually be too old to use even if kept sealed. [19]

Many chemicals bond to the cartridge material fairly irreversibly, through chemisorption. [17] But some adsorbed organic vapours may only bond weakly and reversibly (for example methanol [20] ). These organic vapours, especially the more volatile ones, may desorb from the filter and diffuse through the cartridge while it is not in use, such that they may be breathed by the wearer when they begin to use the cartridge again. [21] [18] For this reason, cartridges used against organic vapours are single-use, unless experimental evidence shows that desorbtion-caused breakthrough after a storage period is not a problem for the specific organic vapours in question. [22] [18]

Chemical cartridges must be replaced when they no longer have the ability to absorb the toxic chemicals, a point which is determined by a qualified industrial hygienist. Cartridge service life is dependent on many factors, [5] [22] including contaminant type and concentrations, interference from other chemicals, breathing rates, whether respirator use is continuous or intermittent, sorption capacity of the cartridges, and environmental factors like humidity and temperature. [23] There is active research into making more types of chemical cartridge with an end-of-service-life indicator (ESLI), which indicates to the user when the cartridge has expired. [24] [21] [23] ESLIs may be moisture-dependent, in which case relying on them for use in dry atmospheres could cause dangerously high exposures. [23]

Traits

Use of respirators in the workplace; see minutes 6:47-8:20 for elastomeric respirators, and 10:10-14:30 for filter types.
This section is an excerpt from Respirator assigned protection factors § US Assigned PF values.[ edit ]

Air-purifying respirators cannot be used in oxygen-deficient atmospheres (less than 19.5% oxygen). Nor can they be used in atmospheres with a contaminant concentration that may be immediately dangerous to life or health, or in unknown atmospheres. In these cases air-supplying respirators must be used. If concentrations of hazardous particulates or gasses that are greater than the occupational exposure limit, U.S. regulations require that respirators be worn, but they may also be worn at lower concentrations. [25] Similar mandatory legal requirements apply to employers in many other countries (examples [26] [27] [28] [29] ). The respirator must have a sufficient assigned protection factor (APF) for the conditions. [25]

Respirators are rated by APF; [30] higher APFs protect more
Type APF protects from
Disposable filtering facepiece respirators 10-30 [31] [25] [32] particulates only
Half-mask elastomeric respirators10-30 [31] [25] [32] both particulates and gasses
Full-face-mask elastomeric respirators50 [25] [32] both particulates and gasses
Loose-hood PAPRs 25 or 50 [25] [32] [33] both particulates and gasses
Elastomeric PAPRs1000 [33] both particulates and gasses
Supplied-air respirators (SARs)10-2000 [25] [32] both particulates and gasses
Self-contained breathing apparatus (SCBAs)50-10 000 [25] [32] both particulates and gasses
Elastomeric masks may fail to protect if they are not donned before entering a hazardous environment. Other problems include using a size other than the size the wearer was fit-tested on, using the wrong sort of cartridge, re-using a cartridge that is no longer good, not doing a positive- and negative-pressure seal check each time the mask is donned, failing to test the respirator (and perhaps inhaling the carbon from a broken cartridge), and even putting the nose-clip up the nose rather than using it to pinch the nose shut. [34]

Fit

Facial hairstyles and filtering facepiece respirators.pdf
A CDC guide to facial hair and respirators
Mask Compatible Combat Spectacle MCU2P.jpg
Mask-compatible eyeglasses, with flat elastomeric straps, to avoid interfering with the seal
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Elastomeric full-face masks being worn with standard eyeglasses.

Fit is critical to the protection provided by elastomeric respirators. Elastomeric masks must be individually fit-tested and inspected for full efficacy. [2] They may be somewhat easier to fit than filtering facepiece respirators. Older mask designs were designed only to fit young adult men of average weight and a narrow range of ethnicities; newer ones use updated anthropometry and fit more people. [5]

Limited research suggests that elastomeric respirators may have better fitting characteristics than disposable filtering-facepiece respirators, fitting a broader variety of faces, and thus being more likely to seal well when the user has not done a formal fit test. Available evidence also suggests that as a class, elastomeric respirators may leak less, and their seals are less likely to become damaged. Elastomeric respirators have wider straps which slip less, individually-adjustable straps, and wider, softer, more flexible seals (see image below); these may help reduce leaks. [5]

Full-face elastomeric respirators generally seal better. [2] For substances hazardous to the eyes, a respirator equipped with a full facepiece, helmet, or hood is recommended. [35]

Eyeglasses can clash with elastomeric masks. Conventionally, full-face masks are modified, with prescription lenses inserted into the mask. Glasses can be worn over a half-mask, as long as they do not interfere with the seal or headstraps. Some users find this uncomfortable. [2] [5] Wearing contacts is not possible where there is a risk of solvent vapours, and may not be advisable if there is an infection risk, [2] but otherwise contacts can be worn. [5]

Facial hair underneath the seal is also a problem. Piercings, jewelry, heavy cosmetics, and some creases and scars can also interfere with sealing. [5]

Straps may stretch slightly over time on some models. [5]

Communication

Klinika BGMU 24.jpg
Swiss Army gas mask model 90-IMG 7570.jpg
Left, Communicating with gestures, in a Russian hospital treating COVID-19 cases. Right, inside a Swiss military respirator, internal mask removed (replaced). The shiny metal shields a membrane for transmitting sounds. The item under the chin is an exhalation valve. The filter is attached to a third port between them, not visible here (outside view). [36]

It is harder to understand the speech of someone wearing most types of elastomeric respirator. This can be dangerous in some environments. Some commercially available respirators include sound-transmitting diaphragms and/or transparent windows giving a view of the mouth, to improve communication efficiency. Designs that allow the jaw to move more freely may also help. Electronic voice relays, from inside the mask or from a throat microphone, have also been used. [5]

Elastomeric respirators without these modifications muffle the wearer's speech more than filtering facepiece respirators (FFRs) such as N95 respirators. In some studies, this was a major reason why healthcare workers preferred to wear FFRs. [5]

Comfort

Extended use of certain negative-pressure respirators can result in higher levels of carbon dioxide from dead space and breathing resistance (pressure drop) which can impact functioning and sometimes can exceed the PEL. [37] [38] [39] This effect was significantly reduced with powered air purifying respirators. [40] Certain respirator designs, especially those with head straps, can also lead to headaches, [41] dermatitis and acne. [42]

Sweat does not evaporate as easily from under a mask; elastomeric respirators may be more hot and humid than FFRs. Heavier respirators cause more fatigue. More breathing resistance causes more fatigue, and makes the wearer more likely to feel out-of-breath or claustrophobic. Tight straps, on any type of respirator, are reported to put pressure on the sinuses and cause headaches. [5]

Exhalation valves

Some masks have exhalation valve that let the exhaled air go out unfiltered. The certification grade of the mask (such as N95) is about the mask itself and it does not warrant any safety about the air that is expelled by the wearer through the valve. A mask with valve mainly increases the comfort of the wearer. [43]

Uses

Firefighters testing elastomeric respirators, for light use in non-oxygen-deficient environments As ausbildung bfkuu denkmayr 0023 (25319235467).jpg
Firefighters testing elastomeric respirators, for light use in non-oxygen-deficient environments
Elastomeric masks are part of the equipment worn in mining P100 half-face respirator.png
Elastomeric masks are part of the equipment worn in mining
Making logs from rice chaff Woodfire by rice residue.jpg
Making logs from rice chaff

First responders may use elastomeric respirators, including during smoke simulation exercises. [5] : Table2-1  Air-purifying respirators are not effective during firefighting, in oxygen-deficient atmosphere, or in an unknown atmosphere; in these situations an air-supplying respirator such as a self-contained breathing apparatus is recommended instead. [35]

The CDC has been recommending elastomeric respirators be used to protect people from droplet and airborne transmission of deadly viruses since 1992. [44]

Gas masks are extensively used in mining and construction. They are used against paint vapors, solvents, silica dust, and other hazardous particles and gasses. [5] Masons and carpenters use them against dusts and adhesives. [5] : Table2-1 

Elastomeric respirators may be used to protect against welding fumes. [45] [5] : Box2-1  Different welding processes may produce different fumes, both particles and gasses such as carbon monoxide. Oxygen displacement by otherwise-harmless shielding gasses is also a risk. [46] [47] A self-contained breathing apparatus may be needed. [45] Respirators used by welders must fit under a welding mask. [48]

Respirators are also used in demolition to protect against asbestos, mould, and other hazardous waste. [49]

Elastomeric respirators are used for cleaning up after oil spills. [50]

Elastomeric respirators are used against chemical aerosols and toxic gases. [5] They are used in the chemical industry when handling hazardous materials; workers are usually issued escape respirators as a precaution against leaks. Workers are instructed to put their mask on and leave immediately to sound the alarm if they detect a leak. Other respirators may be used for making repairs to leaking equipment. [51]

Elastomeric respirators may be worn in agriculture, [5] : fig.2–4  for instance when using agricultural chemicals, solvents, fish meal, silage, mold spores and dust. [52]

Manufacturing also uses elastomeric respirators, [5] : fig.2–4  for instance on assembly lines. [5] : Table2-1  Elastomeric respirators are worn by many employees in the nuclear industry. [5]

Medical use

A CDC video on the use of elastomeric respirators in healthcare

Elastomeric respirators were first used to keep health care workers safe from Tuberculosis in the mid-1990s. The CDC has long recommended health care workers use elastomeric respirators during pandemics to keep themselves safe from droplet and airborne transmission. The CDC recommended health care workers use elastomeric respirators for protection from SARS in 2003, H1N1 in 2009 and COVID-19 in April 2020. [53]

The possibility of wider use during pandemics was being investigated in the US in 2017. [54] In 2017, CDC scientist Lew Radonovich presented the CDC plan to put elastomeric respirators into widespread use during pandemics. In September 2019, Lew Radonovich and the CDC presented the plan to put elastomeric respirators in to widespread use during pandemics at the AOHP Nation conference in Baltimore. In medical use, the elastomeric portions of the mask must also be cleaned and disinfected, as some germs can survive on them for weeks. Conventionally, the filter cartridges are discarded. [2]

Filter cartridges can be hard to find amidst shortages. In emergency situations, if the filters are unclogged and unsoiled but contaminated with germs, the filters could be sterilized and re-used, although the filtration efficiency may be degraded by some forms of disinfection. [2] As of 2020, the available filter materials would be damaged by being dipped or submerged in cleaning fluid, but the outside of [55] the filter cartridges can be cleaned and disinfected by wipes (pancake-style filters cannot be disinfected). [2] During the COVID-19 pandemic, public health authorities issued guidelines on how to save, disinfect and reuse standard mechanical filters, warning against the disinfection methods that damaged filtration efficiency. [56] [57]

Limited research failed to find evidence that elastomeric respirators caused more patient anxiety than FFR masks, including in children and disoriented patients. [5] A single air-filtering elastomeric respirator cost about as much as 40 disposable filtering facepiece respirators, and a medical worker uses about 20 disposable masks per day, according to a 2018 publication. The particulate cartridges cost about as much as six disposable masks. [58] Air-supplying respirators may be easier for hospital personnel to use; they can be worn for longer periods. [1]

Source control

These paragraphs are an excerpt from Source control (respiratory disease) § Exhalation source control with respirators.[ edit ]

Unfiltered exhalation of air is found on both filtering facepiece and elastomeric respirators with exhalation valves. [43] Unfiltered air is also found on powered air-purifying respirators, which cannot ever filter exhaled air. [59] During the COVID-19 pandemic, masks with unfiltered-exhalation valves ran counter to the requirements of some mandatory mask orders. [60] [61] Despite the aforementioned belief, a 2020 research by the NIOSH and CDC shows that an uncovered exhalation valve already provides source control on a level similar to, or even better than, surgical masks. [62] [63]

It is possible to seal some unfiltered exhalation valves [64] or to cover it with an additional surgical mask; this might be done where mask shortages make it necessary. [65] [66] However, so long as there are no shortages, respirators without exhalation valves should still be preferred in situations where source control is necessary. [63]

CBRN defense

Elastomeric respirators may be used for protection from chemical, biological, radiological, and nuclear agents (CBRN). Some elastomeric respirators are specifically certified for such use. [67]

Gas masks were initially widely used in chemical warfare, against the effects of war gas. Chemical and biological weapons are prohibited by customary international humanitarian law, in international and non-international conflicts. Use is considered a war crime. [68] [69] [70]

During demonstrations and protests where tear gas (such as CS gas [71] ) is employed by riot police, gas masks are commonly used by police [72] and demonstrators alike. [73] [74] [75] Journalists covering these events also use respirators, and where use of tear gas spreads into residential areas, even those not on the front lines may buy them. Access to respirators has been restricted by authorities who regard them as tools of resistance, causing circumvention and smuggling. [73]

Cleaning and storage

Cleaning a gas mask in the US Navy Flickr - Official U.S. Navy Imagery - Sailor cleans a gas mask in the hangar bay aboard USS George H.W. Bush.jpg
Cleaning a gas mask in the US Navy

Cleaning procedures are specific to the type and material of mask, and are supplied by the manufacturer. They generally involve washing with soap and water or other chemical disinfectants. [2] Some manufacturer instructions have been shown to be much more difficult to understand than reformulated instructions; the lack of standardization also makes cleaning more complicated. Cleaning may be fairly time-consuming, depending on automation and the manufacturer's instructions. [5]

Depending on materials, elastomeric components of masks may be damaged by some cleaning methods (such as acetone, ethanol, strong hypochlorite and iodine solutions, quaternary ammonium salts, ethylene oxide, or temperatures over 50 °C/122 °F). Cleaning by machine is possible, but cleaning can also be done by hand. [2] [5] The filter material may be damaged and lose effectiveness if it comes into contact with cleaning or disinfecting solutions. Manufacturers generally advise throwing it out each time the mask is cleaned, but this may not be possible in shortage situations. [2]

Drying a mask may take hours, depending on design (elastomeric straps are typically dry within half-an-hour, but cloth straps take longer). Masks should never be stored wet. The facepiece and straps should not be stored in a way that will distort them. [2] Well-maintained elastomeric masks can last for years in industrial use. [5] Users may carry their respirator in a shoulderbag for accessibility. [5] [54]

In construction, elastomeric masks are rarer than disposable mechanical filters; the disposable masks are preferentially issued because supervisors prefer to avoid cleaning and storage. [5] : Box2-1  In industry, when there are few workers, each may be responsible for their own permanently-assigned mask; where there are more workers, there may be a dedicated staff who maintain and reprocess respirators. [5]

Elastomeric respirators may be used by graffiti taggers using aerosol paint canisters. [76]

They are also used by urban explorers venturing into environments where materials such as radioactive particles [77] or asbestos [78] may be present.

Aside from serving their functional purposes, gas masks are also used as fashion in cybergoth wear. [79] They are also used as emblems by some musicians. [80]

See also

Further reading

Related Research Articles

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A gas mask is a piece of personal protective equipment 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. Gas masks only protect the user from ingesting or inhaling chemical agents, as well as preventing contact with the user's eyes. Most combined gas mask filters will last around 8 hours in a biological or chemical situation. Filters against specific chemical agents can last up to 20 hours.

<span class="mw-page-title-main">Personal protective equipment</span> 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, chemical, 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.

<span class="mw-page-title-main">Surgical mask</span> Mouth and nose cover against bacterial aerosols

A surgical mask, also known by other names such as a medical face mask or procedure mask, is a personal protective equipment used by healthcare professionals that serves as a mechanical barrier that interferes with direct airflow in and out of respiratory orifices. This helps reduce airborne transmission of pathogens and other aerosolized contaminants between the wearer and nearby people via respiratory droplets ejected when sneezing, coughing, forceful expiration or unintentionally spitting when talking, etc. Surgical masks may be labeled as surgical, isolation, dental or medical procedure masks.

<span class="mw-page-title-main">Respirator</span> Device worn to protect the user from inhaling contaminants

A respirator is a device designed to protect the wearer from inhaling hazardous atmospheres including lead fumes, vapors, 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.

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

<span class="mw-page-title-main">Immediately dangerous to life or health</span> 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."

<span class="mw-page-title-main">Respirator fit test</span> Safety procedure for testing PPE air-tightness

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.

<span class="mw-page-title-main">Chemical cartridge</span> Container that cleans pollution from air inhaled through it

A respirator cartridge or gas mask 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-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, devoted to research on 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.

<span class="mw-page-title-main">NIOSH air filtration rating</span> U.S. rating of respirators

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 solid and liquid particulates 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.

<span class="mw-page-title-main">Powered air-purifying respirator</span> Full-face respirator that provides filtered air to the wearer using an electric fan

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.

<span class="mw-page-title-main">Respirator assigned protection factors</span>

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.

<span class="mw-page-title-main">Workplace respirator testing</span> 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.

<span class="mw-page-title-main">N95 respirator</span> Particulate respirator meeting the N95 standard

An N95 respirator is a disposable filtering facepiece respirator or reusable elastomeric respirator filter that meets the U.S. National Institute for Occupational Safety and Health (NIOSH) N95 standard of air filtration, filtering at least 95% of airborne particles that have a mass median aerodynamic diameter of 0.3 micrometers under 42 CFR 84, effective July 10, 1995. A surgical N95 is also rated against fluids, and is regulated by the US Food and Drug Administration under 21 CFR 878.4040, in addition to NIOSH 42 CFR 84. 42 CFR 84, the federal standard which the N95 is part of, was created to address shortcomings in the prior United States Bureau of Mines respirator testing standards, as well as tuberculosis outbreaks, caused by the HIV/AIDS epidemic in the United States. Since then, N95 respirator has continued to be solidified as a source control measure in various pandemics that have been experienced in the United States and Canada, including the 2009 swine flu and the COVID-19 pandemic.

<span class="mw-page-title-main">Mechanical filter (respirator)</span> Air-filtering face masks or mask attachments

Mechanical filters, a part of particulate respirators, 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.

<span class="mw-page-title-main">Face masks during the COVID-19 pandemic</span> Health control procedure against COVID-19

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<span class="mw-page-title-main">Source control (respiratory disease)</span> Strategy for reducing disease transmission

Source control is a strategy for reducing disease transmission by blocking respiratory secretions produced through breathing, speaking, coughing, sneezing or singing. Multiple source control techniques can be used in hospitals, but for the general public wearing personal protective equipment during epidemics or pandemics, respirators provide the greatest source control, followed by surgical masks, with cloth face masks recommended for use by the public only when there are shortages of both respirators and surgical masks.

The European respirator standards refer to the filtering classification by EN 149, EN 14683, and EN 143, all European standards of testing and marking requirements for respirators. FFP standard masks cover the nose, mouth and chin and may have inhalation and/or exhalation valves.

<span class="mw-page-title-main">Supplied-air respirator</span> Breathing apparatuus remotely supplied by an air hose

A supplied-air respirator (SAR) or air-line respirator is a breathing apparatus used in places where the ambient air may not be safe to breathe. 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 high pressure cylinders, while SAR users get it from a remote stationary air supply connected to them by a hose. They may be equipped with a backup air tank in case the air-line gets cut.

<span class="mw-page-title-main">Glossary of breathing apparatus terminology</span> Definitions of technical terms used in connection with breathing apparatus

A breathing apparatus or breathing set is equipment which allows a person to breathe in a hostile environment where breathing would otherwise be impossible, difficult, harmful, or hazardous, or assists a person to breathe. A respirator, medical ventilator, or resuscitator may also be considered to be breathing apparatus. Equipment that supplies or recycles breathing gas other than ambient air in a space used by several people is usually referred to as being part of a life-support system, and a life-support system for one person may include breathing apparatus, when the breathing gas is specifically supplied to the user rather than to the enclosure in which the user is the occupant.

References

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