![Paulodj](https://upload.wikimedia.org/wikipedia/commons/b/b5/Paulodj.jpg)
Elastomeric respirators, also called reusable air-purifying respirators,
seal to the face with
elastomer
An elastomer is a polymer with viscoelasticity (i.e. both viscosity and elasticity) and with weak intermolecular forces, generally low Young's modulus and high failure strain compared with other materials. The term, a portmanteau of ''elastic p ...
ic material, which may be a
natural
Nature, in the broadest sense, is the physical world or universe. "Nature" can refer to the phenomena of the physical world, and also to life in general. The study of nature is a large, if not the only, part of science. Although humans are p ...
or
synthetic rubber
A synthetic rubber is an artificial elastomer. They are polymers synthesized from petroleum byproducts. About 32-million metric tons of rubbers are produced annually in the United States, and of that amount two thirds are synthetic. Synthetic rubbe ...
. They are generally reusable.
Full-face versions of elastomeric
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 ...
s seal better and protect the eyes.
Elastomeric respirators consist of a reusable mask that seals to the face, with exchangeable filters.
Elastomeric respirators can be used with
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 ...
filters that remove gases,
mechanical filters that retain particulate matter, or both. As particulate filters, they are comparable
(or, due to the quality and error-tolerance of the elastomeric seal, possibly superior
[ (free fulltext)]) to
filtering facepiece respirator
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.
Mechanism of operation
Mechanical filter respirator ...
s such as
N95 respirator
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 and
FFP masks.
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. Some, but not all, filter materials are
proprietary and manufacturer-specific,
and supply-chain failures can make replacements hard to find.
Although
powered air-purifying respirator
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 pathoge ...
s and
air-supplying respirators may have elastomeric masks, they are not generally referred to as elastomeric respirators.
Physical form
![P100 fullface elastomeric respirator](https://upload.wikimedia.org/wikipedia/commons/8/8d/P100_fullface_elastomeric_respirator.png)
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.
Air-purifying respirators draw the surrounding air through filters which remove contaminants.
[
A range of ]elastomer
An elastomer is a polymer with viscoelasticity (i.e. both viscosity and elasticity) and with weak intermolecular forces, generally low Young's modulus and high failure strain compared with other materials. The term, a portmanteau of ''elastic p ...
s are used, including silicone
A silicone or polysiloxane is a polymer made up of siloxane (−R2Si−O−SiR2−, where R = organic group). They are typically colorless oils or rubber-like substances. Silicones are used in sealants, adhesives, lubricants, medicine, cooking ...
, neoprene
Neoprene (also polychloroprene) is a family of synthetic rubbers that are produced by polymerization of chloroprene.Werner Obrecht, Jean-Pierre Lambert, Michael Happ, Christiane Oppenheimer-Stix, John Dunn and Ralf Krüger "Rubber, 4. Emulsion R ...
, EPDM (ethylene propylene diene monomer rubber
Ethylene (IUPAC name: ethene) is a hydrocarbon which has the formula or . It is a colourless, flammable gas with a faint "sweet and musky" odour when pure. It is the simplest alkene (a hydrocarbon with carbon-carbon double bonds).
Ethylene i ...
), or proprietary elastomers such as Hycar. Latex
Latex is an emulsion (stable dispersion) of polymer microparticles in water. Latexes are found in nature, but synthetic latexes are common as well.
In nature, latex is found as a milky fluid found in 10% of all flowering plants (angiosperms ...
is rarely used due to allergies. Many manufacturers offer a choice of two materials.
Elastomeric respirators include:
* ''mouth-bit respirators'', which fit in the mouth with the nose pinched shut (escape only)
* ''quarter-mask'' or orinasal mask
An orinasal mask, oro-nasal mask or oral-nasal mask is a Breathing mask (disambiguation), 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 ...
, covering the mouth and nose only
* ''half-mask'', from below the eyes to below the chin
* ''fullface mask'', from above the eyes to below the chin
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. It may also reduce inwards leakage. However, masks which do not filter exhaled air cannot be used for source control
In software engineering, version control (also known as revision control, source control, or source code management) is a class of systems responsible for managing changes to computer programs, documents, large web sites, or other collections o ...
.
Filter types
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.[ (''reviewed April 9th'')] An appropriate standard of filter must be used for the mask to be effective.
Filters may be contained in cartridges or canisters; there are also flexible flat and pancake-style filters (see illustrations). 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.[
]
Particulate filters
, 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). Disinfection and reuse techniques have been tested for emergency use; some, like soap and water, destroy traditional disposable electret filters by removing the electret
An electret (formed as a portmanteau of ''electr-'' from "electricity" and ''-et'' from "magnet") is a dielectric material that has a quasi-permanent electric charge or dipole polarisation. An electret generates internal and external electric fi ...
charge. Launderable, reusable electret filters were being developed during the COVID-19 pandemic.
Particulate filters may be simple disks or other shapes of flat filter material, which are lightweight, or they may be pancake-style hollow discs with a smaller central plastic connecting tube on one side. 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.
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 mask
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 re ...
s, utilizing them as filter discs (as shown above). Six filter discs can be cut from one mask.
Like other proprietary refills, proprietary filter cartridges cause vendor lock-in
In economics, vendor lock-in, also known as proprietary lock-in or customer lock-in, makes a customer dependent on a vendor for products, unable to use another vendor without substantial switching costs.
The use of open standards and alternative ...
.
Chemical cartridges
Different types of cartridge must be used to filter out different chemicals. Most cartridges are made of activated charcoal
"Activated" is a song by English singer Cher Lloyd. It was released on 22 July 2016 through Vixen Records. The song was made available to stream exclusively on ''Rolling Stone'' a day before to release (on 21 July 2016).
Background
In an interv ...
, which has a very high surface area to adsorb
Adsorption is the adhesion of atoms, ions or molecules from a gas, liquid or dissolved solid to a surface. This process creates a film of the ''adsorbate'' on the surface of the ''adsorbent''. This process differs from absorption, in which a fl ...
toxins onto. These carbon filters are often impregnated with reagent
In chemistry, a reagent ( ) or analytical reagent is a substance or compound added to a system to cause a chemical reaction, or test if one occurs. The terms ''reactant'' and ''reagent'' are often used interchangeably, but reactant specifies a ...
s which react and bond with the specific airborne chemical(s) the cartridge targets. This process is called chemisorption
Chemisorption is a kind of adsorption which involves a chemical reaction between the surface and the adsorbate. New chemical bonds are generated at the adsorbent surface. Examples include macroscopic phenomena that can be very obvious, like cor ...
; 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
DABCO (1,4-diazabicyclo .2.2ctane), also known as triethylenediamine or TEDA, is a bicyclic organic compound with the formula N2(C2H4)3. This colorless solid is a highly nucleophilic tertiary amine base, which is used as a catalyst and reagent ...
(TEDA) Many chemicals cannot be safely filtered out by any chemical cartridge.[
Chemical cartridges must generally be kept sealed from the air until use, and will eventually be too old to use even if kept sealed.]
Many chemicals bond to the cartridge material fairly irreversibly, through chemisorption
Chemisorption is a kind of adsorption which involves a chemical reaction between the surface and the adsorbate. New chemical bonds are generated at the adsorbent surface. Examples include macroscopic phenomena that can be very obvious, like cor ...
. But some adsorbed
Adsorption is the adhesion of atoms, ions or molecules from a gas, liquid or dissolved solid to a surface. This process creates a film of the ''adsorbate'' on the surface of the ''adsorbent''. This process differs from absorption, in which a ...
organic vapours may only bond weakly and reversibly (for example methanol
Methanol (also called methyl alcohol and wood spirit, amongst other names) is an organic chemical and the simplest aliphatic alcohol, with the formula C H3 O H (a methyl group linked to a hydroxyl group, often abbreviated as MeOH). It is a ...
). 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. 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.[
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,] 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.[ 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.] ESLIs may be moisture-dependent, in which case relying on them for use in dry atmospheres could cause dangerously high exposures.[
]
Traits
Air-purifying 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 respi ...
s cannot be used in 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 ...
s (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
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 ...
, 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
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 ...
, U.S. regulations require that respirators be worn, but they may also be worn at lower concentrations. Similar mandatory legal requirements apply to employers in many other countries (examples). The respirator must have a sufficient assigned protection factor (APF) for the conditions.
Elastomeric masks may fail to protect if they are not donned ''before'' investigating a funny smell. They will not protect if they are kept far away or in fiddly packaging so that they can not be donned within a single breath when a problem occurs. They will not protect if the user, without practice in being unable to breathe, panics and attempts to run rather than don the respirator. 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.
Fit
Fit is critical to the protection provided by elastomeric respirators. Elastomeric masks must be individually fit-tested and inspected for full efficacy. 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
Anthropometry () refers to the measurement of the human individual. An early tool of physical anthropology, it has been used for identification, for the purposes of understanding human physical variation, in paleoanthropology and in various atte ...
and fit more people.
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.
Full-face elastomeric respirators generally seal better. For substances hazardous to the eyes, a respirator equipped with a full facepiece, helmet, or hood is recommended.[ For download on ]Wikimedia Commons
Wikimedia Commons (or simply Commons) is a media repository of free-to-use images, sounds, videos and other media. It is a project of the Wikimedia Foundation.
Files from Wikimedia Commons can be used across all of the Wikimedia projects in ...
: PDF fulltext
Eyeglasses
Glasses, also known as eyeglasses or spectacles, are vision eyewear, with lenses (clear or tinted) mounted in a frame that holds them in front of a person's eyes, typically utilizing a bridge over the nose and hinged arms (known as temples or ...
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. Wearing contacts is not possible where there is a risk of solvent vapours, and may not be advisable if there is an infection risk, but otherwise contacts can be worn.
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, ...
underneath the seal is also a problem. Piercings, jewelry, heavy cosmetics, and some creases and scars can also interfere with sealing.
Straps may stretch slightly over time on some models.
Communication
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
A throat microphone, also called a laryngophone, is a type of contact microphone that absorbs vibrations directly from the wearer's throat by way of single or dual sensors worn against the neck. The sensors, called transducers, can pick up speec ...
, have also been used.
Elastomeric respirators without these modifications muffle the wearer's speech more than filtering facepiece respirator
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.
Mechanism of operation
Mechanical filter respirator ...
s (FFRs) such as N95 respirator
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. In some studies, this was a major reason why healthcare workers preferred to wear FFRs.
Comfort
Many air-purifying respirators without air supply provide the workers with clean (purified) air with an excessively high concentration of carbon dioxide. For example, in the U.S. the permissible exposure limit
The permissible exposure limit (PEL or OSHA PEL) is a legal limit in the United States for exposure of an employee to a chemical substance or physical agent such as high level noise. Permissible exposure limits are established by the Occupational S ...
for CO2 is 9 g/m3 (0.5% by volume) over an 8-hour shift, and 27 g/m3 (1.4% by volume) over any 15 minute period. But values measured for elastomeric respirators can increase to 2.6%. There is a lack of studies on the oxygen and carbon dioxide levels in the dead space behind an elastomeric respirator, but this may also cause headaches, especially if worn continuously for over 4 hours.
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
Claustrophobia is the fear of confined spaces. It can be triggered by many situations or stimuli, including elevators, especially when crowded to capacity, windowless rooms, and hotel rooms with closed doors and sealed windows. Even bedrooms with ...
. Tight straps, on any type of respirator, are reported to put pressure on the sinuses and cause headaches.
Uses
First responders may use elastomeric respirators, including during smoke simulation exercises. Air-purifying respirators 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 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 an air-supplying respirator such as 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 ...
is recommended instead.
The CDC has been recommending elastomeric respirators be used to protect people from droplet and airborne transmission of deadly viruses since 1992.
Gas masks are extensively used in mining and construction. They are used against paint vapors, solvents, silica dust
Silicon dioxide, also known as silica, is an oxide of silicon with the chemical formula , most commonly found in nature as quartz and in various living organisms. In many parts of the world, silica is the major constituent of sand. Silica is ...
, and other hazardous particles and gasses. Masons and carpenters use them against dusts and adhesives.
Elastomeric respirators may be used to protect against welding fumes. Different welding processes may produce different fumes, both particles and gasses such as carbon monoxide
Carbon monoxide (chemical formula CO) is a colorless, poisonous, odorless, tasteless, flammable gas that is slightly less dense than air. Carbon monoxide consists of one carbon atom and one oxygen atom connected by a triple bond. It is the simple ...
. Oxygen displacement by otherwise-harmless shielding gas
Shielding gases are inert or semi-inert gases that are commonly used in several welding processes, most notably gas metal arc welding and gas tungsten arc welding (GMAW and GTAW, more popularly known as MIG (Metal Inert Gas) and TIG (Tungsten Iner ...
ses is also a risk. 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 ...
may be needed. Respirators used by welders must fit under a welding mask A welding helmet is a type of personal protective equipment used in performing certain types of welding to protect the eyes, face, and neck from flash burn, sparks, infrared and ultraviolet light, and intense heat. The modern welding helmet used to ...
.
Respirators are also used in demolition to protect against asbestos
Asbestos () is a naturally occurring fibrous silicate mineral. There are six types, all of which are composed of long and thin fibrous crystals, each fibre being composed of many microscopic "fibrils" that can be released into the atmosphere b ...
, mould, and other hazardous waste.[ (free fulltext)]
Elastomeric respirators are used for cleaning up after oil spill
An oil spill is the release of a liquid petroleum hydrocarbon into the environment, especially the marine ecosystem, due to human activity, and is a form of pollution. The term is usually given to marine oil spills, where oil is released into th ...
s.
Elastomeric respirators are used against chemical aerosols and toxic gases. They are used in the chemical industry when handling hazardous materials
Dangerous goods, abbreviated DG, are substances that when transported are a risk to health, safety, property or the environment. Certain dangerous goods that pose risks even when not being transported are known as hazardous materials ( syllabi ...
; 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.
Elastomeric respirators may be worn in agriculture, for instance when using agricultural chemicals, solvents, fish meal
Fish meal is a commercial product made from whole wild-caught fish, bycatch and fish by-products to feed farm animals, e.g., pigs, poultry, and farmed fish.R. D. Miles and F. A. Chapman.FA122: The Benefits of Fish Meal in Aquaculture DietsFisheri ...
, silage
Silage () is a type of fodder made from green foliage crops which have been preserved by fermentation to the point of acidification. It can be fed to cattle, sheep and other such ruminants (cud-chewing animals). The fermentation and storage p ...
, mold spore
In biology, a spore is a unit of sexual or asexual reproduction that may be adapted for dispersal and for survival, often for extended periods of time, in unfavourable conditions. Spores form part of the life cycles of many plants, algae, f ...
s and dust.
Manufacturing also uses elastomeric respirators, for instance on assembly lines. Elastomeric respirators are worn by many employees in the nuclear industry.
Medical use
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.
The possibility of wider use during pandemics was being investigated in the US in 2017. 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.
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. , the available filter materials would be damaged by being dipped or submerged in cleaning fluid, but the outside of the filter cartridges can be cleaned and disinfected by wipes (pancake-style filters cannot be disinfected). 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.
Limited research failed to find evidence that elastomeric respirators caused more patient anxiety than FFR masks, including in children and disoriented patients. 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. Air-supplying respirators may be easier for hospital personnel to use; they can be worn for longer periods.
Source control
Elastomeric respirators with one-way valves that release unfiltered exhaled air are not recommended in disease-control settings where the unfiltered exhaled air might infect others, but can be used in some other settings. In pandemics, masks with exhalation valves may not meet the requirements of some public-health orders. If respirators with filtered exhalation valves are not available, those with unfiltered exhalation valves may be altered to filter exhalation air, e.g., by using an anesthesia circuit filter. Or the wearer may simply cover the exhalation valve with a surgical mask or other suitable source control material. Care must be taken so that the additional filtration does not impede exhalation to the point that breathing becomes restricted or that excessive buildup occurs.
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.
Gas mask
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 mask ...
s were initially widely used in chemical warfare, against the effects of war gas. Chemical and biological weapons are prohibited by customary
Custom, customary, or consuetudinary may refer to:
Traditions, laws, and religion
* Convention (norm), a set of agreed, stipulated or generally accepted rules, norms, standards or criteria, often taking the form of a custom
* Norm (social), a r ...
international humanitarian law
International humanitarian law (IHL), also referred to as the laws of armed conflict, is the law that regulates the conduct of war (''jus in bello''). It is a branch of international law that seeks to limit the effects of armed conflict by prot ...
, in international and non-international conflicts. Use is considered a war crime.
During demonstrations and protests where tear gas
Tear gas, also known as a lachrymator agent or lachrymator (), sometimes colloquially known as "mace" after the early commercial aerosol, is a chemical weapon that stimulates the nerves of the lacrimal gland in the eye to produce tears. In ad ...
(such as CS gas
The compound 2-chlorobenzalmalononitrile (also called ''o''-chlorobenzylidene malononitrile; chemical formula: C10H5ClN2), a cyanocarbon, is the defining component of tear gas commonly referred to as CS gas, which is used as a riot control agent ...
) is employed by riot police, gas masks are commonly used by police and demonstrators alike. 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.
File:A mother and baby both in gas-masks during 1941. D3918.jpg, A mother and baby, both in gas masks, during WWII
World War II or the Second World War, often abbreviated as WWII or WW2, was a world war that lasted from 1939 to 1945. It involved the vast majority of the world's countries—including all of the great powers—forming two opposin ...
.
File:Emergency personnel respond to the Tokyo subway sarin attack.png, Japan Self-Defense Force
The Japan Self-Defense Forces ( ja, 自衛隊, Jieitai; abbreviated JSDF), also informally known as the Japanese Armed Forces, are the unified ''de facto''Since Article 9 of the Japanese Constitution outlaws the formation of armed forces, th ...
chemical troops respond to the Tokyo subway sarin attack
The was an act of domestic terrorism perpetrated on 20 March 1995, in Tokyo, Japan, by members of the cult movement Aum Shinrikyo. In five coordinated attacks, the perpetrators released sarin on three lines of the Tokyo Metro (then ''Teito Rapi ...
in 1995
File:2020-08-23 PPB North Precinct Protest (50274961266).jpg, A protester at a demonstration in 2020
Cleaning and storage
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. 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.
Depending on materials, elastomer
An elastomer is a polymer with viscoelasticity (i.e. both viscosity and elasticity) and with weak intermolecular forces, generally low Young's modulus and high failure strain compared with other materials. The term, a portmanteau of ''elastic p ...
ic components of masks may be damaged by some cleaning methods (such as acetone
Acetone (2-propanone or dimethyl ketone), is an organic compound with the formula . It is the simplest and smallest ketone (). It is a colorless, highly volatile and flammable liquid with a characteristic pungent odour.
Acetone is miscib ...
, ethanol
Ethanol (abbr. EtOH; also called ethyl alcohol, grain alcohol, drinking alcohol, or simply alcohol) is an organic compound. It is an Alcohol (chemistry), alcohol with the chemical formula . Its formula can be also written as or (an ethyl ...
, strong hypochlorite
In chemistry, hypochlorite is an anion with the chemical formula ClO−. It combines with a number of cations to form hypochlorite salts. Common examples include sodium hypochlorite (household bleach) and calcium hypochlorite (a component of ble ...
and iodine
Iodine is a chemical element with the symbol I and atomic number 53. The heaviest of the stable halogens, it exists as a semi-lustrous, non-metallic solid at standard conditions that melts to form a deep violet liquid at , and boils to a vi ...
solutions, quaternary ammonium salts
In chemistry, quaternary ammonium cations, also known as quats, are positively charged polyatomic ions of the structure , R being an alkyl group or an aryl group. Unlike the ammonium ion () and the primary, secondary, or tertiary ammonium cations ...
, ethylene oxide
Ethylene oxide is an organic compound with the chemical formula, formula . It is a cyclic ether and the simplest epoxide: a three-membered Ring (chemistry), ring consisting of one oxygen atom and two carbon atoms. Ethylene oxide is a colorless a ...
, or temperatures over 50 °C/122 °F). Cleaning by machine is possible, but cleaning can also be done by hand. 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.
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. Well-maintained elastomeric masks can last for years in industrial use. Users may carry their respirator in a shoulderbag for accessibility.[
In construction, elastomeric masks are rarer than disposable mechanical filters; the disposable masks are preferentially issued because supervisors prefer to avoid cleaning and storage.] 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.
In popular culture
Elastomeric respirators may be used by graffiti
Graffiti (plural; singular ''graffiti'' or ''graffito'', the latter rarely used except in archeology) is art that is written, painted or drawn on a wall or other surface, usually without permission and within public view. Graffiti ranges from s ...
taggers using aerosol paint canisters.
They are also used by urban explorers
Urban exploration (often shortened as UE, urbex and sometimes known as roof and tunnel hacking) is the exploration of manmade structures, usually abandoned ruins or hidden components of the manmade environment. Photography and historical inter ...
venturing into environments where materials such as radioactive particles or asbestos may be present.
Aside from serving their functional purposes, gas masks are also used as fashion in cybergoth
Cybergoth is a subculture that derives from elements of goth, raver, rivethead and cyberpunk fashion.
Opinion differs as to whether cybergoth has the requisite complexity to constitute a subculture, with some commentators suggesting that it is ...
wear.[Valerie Steele, ''Gothic: Dark Glamour'', ]Yale University Press
Yale University Press is the university press of Yale University. It was founded in 1908 by George Parmly Day, and became an official department of Yale University in 1961, but it remains financially and operationally autonomous.
, Yale Universi ...
, 2008, pp. 49–50 They are also used as emblems by some musicians.
File:Artist spray painting flowers (Unsplash).jpg, Spray-painting flowers in an elastomeric respirator
File:Wendy Ailan.jpg, A respirator as part of a dancer's cybergoth
Cybergoth is a subculture that derives from elements of goth, raver, rivethead and cyberpunk fashion.
Opinion differs as to whether cybergoth has the requisite complexity to constitute a subculture, with some commentators suggesting that it is ...
outfit.
File:Mike Patton-30 (cropped for context).jpg, A singer, Mike Patton
Michael Allan Patton (born January 27, 1968) is an American singer, producer, film composer and voice actor, best known as the lead vocalist of the alternative metal band Faith No More. Noted for his vocal proficiency, diverse singing techni ...
, performing in an elastomeric respirator (but without its filter cartridges) in 2002. Note microphone
A microphone, colloquially called a mic or mike (), is a transducer that converts sound into an electrical signal. Microphones are used in many applications such as telephones, hearing aids, public address systems for concert halls and public ...
.
See also
* 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 ...
for other types of respirators
** Air-purifying 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 respi ...
s like elastomeric respirators are somewhat less protective than some air-supplying respirators.[
** A ]powered air-purifying respirator
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 pathoge ...
is an elastomeric mask with a battery-powered fan to force air in (except loose-fitting PAPRs)
* 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 chemical filters used with elastomeric respirators
* Mechanical filter respirator
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.
Mechanism of operation
Mechanical filter respirator ...
for other types of particulate filters
* 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.
This is achieved b ...
Further reading
*
*
*
References
External links
* {{Cite news , last=Jacobs , first=Andrew , date=2022-07-03 , title=A Clunky Mask May Be the Answer to Airborne Disease and N95 Waste , language=en-US , work=The New York Times , url=https://www.nytimes.com/2022/07/03/health/covid-ppe-masks-health-care.html , access-date=2022-07-05 , issn=0362-4331
Functional masks
Safety clothing
Respirators