Elastomeric respirator
![](http://upload.wikimedia.org/wikipedia/commons/thumb/0/0d/Police_officer_wearing_half-mask_respirator.jpg/220px-Police_officer_wearing_half-mask_respirator.jpg)
![](http://upload.wikimedia.org/wikipedia/commons/thumb/b/b5/Paulodj.jpg/220px-Paulodj.jpg)
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]
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
[edit]![](http://upload.wikimedia.org/wikipedia/commons/thumb/8/8d/P100_fullface_elastomeric_respirator.png/220px-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.[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]
- mouth-bit respirators, which fit in the mouth with the nose pinched shut (escape only)
- quarter-mask or orinasal mask, 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.[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
[edit]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
[edit]As of 2020[update], 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
[edit]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
[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]
Type | APF | protects from |
---|---|---|
Disposable filtering facepiece respirators | 10-30[31][25][32] | particulates only |
Half-mask elastomeric respirators | 10-30[31][25][32] | both particulates and gasses |
Full-face-mask elastomeric respirators | 50[25][32] | both particulates and gasses |
Loose-hood PAPRs | 25 or 50[25][32][33] | both particulates and gasses |
Elastomeric PAPRs | 1000[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 |
Fit
[edit]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
[edit]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
[edit]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
[edit]Uses
[edit]![](http://upload.wikimedia.org/wikipedia/commons/thumb/5/55/As_ausbildung_bfkuu_denkmayr_0023_%2825319235467%29.jpg/220px-As_ausbildung_bfkuu_denkmayr_0023_%2825319235467%29.jpg)
![](http://upload.wikimedia.org/wikipedia/commons/thumb/2/29/P100_half-face_respirator.png/220px-P100_half-face_respirator.png)
![](http://upload.wikimedia.org/wikipedia/commons/thumb/d/d7/Woodfire_by_rice_residue.jpg/220px-Woodfire_by_rice_residue.jpg)
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
[edit]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[update], 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
[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
[edit]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]
-
A mother and baby, both in gas masks, during WWII.
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Japan Self-Defense Force chemical troops respond to the Tokyo subway sarin attack in 1995
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A protester at a demonstration in 2020
Cleaning and storage
[edit]![](http://upload.wikimedia.org/wikipedia/commons/thumb/7/71/Flickr_-_Official_U.S._Navy_Imagery_-_Sailor_cleans_a_gas_mask_in_the_hangar_bay_aboard_USS_George_H.W._Bush.jpg/220px-Flickr_-_Official_U.S._Navy_Imagery_-_Sailor_cleans_a_gas_mask_in_the_hangar_bay_aboard_USS_George_H.W._Bush.jpg)
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]
In popular culture
[edit]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]
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Spray-painting flowers in an elastomeric respirator
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A respirator as part of a dancer's cybergoth outfit.
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A singer, Mike Patton, performing in an elastomeric respirator (but without its filter cartridges) in 2002. Note microphone.
See also
[edit]- Respirator for other types of respirators
- Air-purifying respirators like elastomeric respirators are somewhat less protective than some air-supplying respirators.[5]
- A powered air-purifying respirator is an elastomeric mask with a battery-powered fan to force air in (except loose-fitting PAPRs)
- Chemical cartridge for chemical filters used with elastomeric respirators
- Mechanical filter respirator for other types of particulate filters
- Respirator fit test
Further reading
[edit]- Mariano Zafra; Javier Salas (2020-10-28). "A room, a bar and a classroom: how the coronavirus is spread through the air". El País. Retrieved 2021-04-20.
- Conocimiento, Ventana al (2021-02-11). "What Have We Learned About Face Masks?". OpenMind. Retrieved 2021-04-20.
References
[edit]- ^ a b c "PPE Image Gallery: Respiratory Protective Equipment - Civilian - Radiation Emergency Medical Management". www.remm.nlm.gov.
- ^ a b c d e f g h i j k l m n o p q r s t "Elastomeric Respirators: Strategies During Conventional and Surge Demand Situations". U.S. Centers for Disease Control and Prevention. 11 February 2020. Archived from the original on 2023-02-11.
- ^ a b c d Bach, Michael (6 July 2017). "Understanding respiratory protection options in Healthcare: The Overlooked Elastomeric". NIOSH Science Blog. CDC.
- ^ a b "Respirator Trusted-Source Information: What are they?". U.S. National Institute for Occupational Safety and Health. 2018-01-29. Retrieved 2020-03-27.
- ^ a b c d e f g h i j k l m n o p q r s t u v w x y z aa ab ac ad ae af Liverman CT, Yost OC, Rogers BM, et al., eds. (2018-12-06). "Elastomeric Respirators". Reusable Elastomeric Respirators in Health Care: Considerations for Routine and Surge Use. National Academies Press.
- ^ CDC (2020-02-11). "Healthcare Workers". Centers for Disease Control and Prevention. Retrieved 2022-04-23.
- ^ a b Alan (22 June 2020). "Open-Source N95 Respirator Mask in the Works". Science and Enterprise.
- ^ a b "Understanding Respiratory Protection Against SARS". www.cdc.gov. NPPT, NIOSH, CDC. 5 June 2020. (reviewed April 9th)
- ^ Canadian Centre for Occupational Health and Safety (16 August 2020). "Respirators - Respirator Selection: OSH Answers". www.ccohs.ca. Government of Canada.
- ^ a b Godoy, Laura R. Garcia; Jones, Amy E.; Anderson, Taylor N.; Fisher, Cameron L.; Seeley, Kylie M. L.; Beeson, Erynn A.; Zane, Hannah K.; Peterson, Jaime W.; Sullivan, Peter D. (1 May 2020). "Facial protection for healthcare workers during pandemics: a scoping review". BMJ Global Health. 5 (5): e002553. doi:10.1136/bmjgh-2020-002553. ISSN 2059-7908. PMC 7228486. PMID 32371574.
- ^ see image above
- ^ "8000 Series Respirators Particulate Filters, NIOSH Certified". Moldex.
- ^ "Low-Profile Disk Filter, P100, PK2". Grainger Supply.
- ^ Hines, Stella E (April 15, 2020). "Elastomeric Respirators in Healthcare: Lessons learned and adaptation for COVID-19". US National Institutes of Health. Retrieved 7 September 2020.
- ^ Chow, Vivienne. "From protests to coronavirus, a mask revolution has been taking place in Hong Kong". Quartz. Retrieved 10 September 2020., mask type shown here
- ^ Morrison, Robert W. (30 November 2002). "Overview of Current Collective Protection Filtration Technology". Homeland Security Digital Library. U.S. Army Soldier and Biological Chemical Command.
- ^ a b "Reuse of Organic Vapor Chemical Cartridges" (PDF). Technical Data Bulletin. 3M. October 2012. #142.
- ^ a b c "NIOSH eliminates maximum use concentrations (MUC) labeling requirement for Chemical Cartridges. | Occupational Safety and Health Administration". www.osha.gov. 3 March 1999. 1910.134(d)(1)(ii).
- ^ "Respirator Fact Sheet, What You Should Know". Centers for Disease Control. 5 June 2020.
- ^ E. Balieu (1983). "Respirator filters in protection against low-boiling compounds". Journal of the International Society for Respiratory Protection. 1 (1): 125–138. ISSN 0892-6298. Retrieved 20 June 2020.
- ^ a b "Cartridge Change Frequently Asked Questions (FAQs)" (PDF). #M.
- ^ a b "Respiratory Protection eTool - Respirator Change Schedules". www.osha.gov. [US] Occupational Safety and Health Administration. Retrieved 2019-12-08.
- ^ a b c [US] Occupational Safety and Health Administration. "Respiratory Protection". www.osha.gov. 63:1152-1300.
- ^ Favas, George (July 2005). End of Service Life Indicator (ESLI) for Respirator Cartridges. Part I: Literature Review. Victoria, Australia: Human Protection & Performance Division, Defence Science and Technology Organisation. p. 49. Archived from the original on May 2, 2013.
- ^ a b c d e f g h Bollinger, Nancy (2004-10-01). "NIOSH respirator selection logic". U.S. National Institute for Occupational Safety and Health: 5–16. doi:10.26616/NIOSHPUB2005100. Retrieved 2020-04-20. For download on Wikimedia Commons: PDF fulltext
- ^ Japan Safety Appliances Association & Japan Standards Association (2006). JIS T 8150: 2006. Guidance for selection, use and maintenance of respiratory protective devices = 呼吸用保護具の選択,使用及び保守管理方法 (in Japanese). Tokyo: Japan Standards Association. p. 22.
- ^ CAN/CSA-Z94.4-11. Selection, use, and care of respirators. Ottawa, Ontario: Canadian Standards Association International. 2012. p. 111. ISBN 978-1-55491-684-9.
- ^ Средства за защита на дихателните органи. Препоръки за избор, употреба, грижи и поддържане (in Bulgarian). София: Български институт за стандартизация. p. 54.
- ^ AS/NZS 1715:2009 "Selection, use and maintenance of respiratory protective equipment". Sidney, New South Wales: Standards Australia. 2009. p. 105. ISBN 978-0-7337-9000-3.
- ^ Radonovich, Lew (September 5, 2017). "Elastomeric and Powered-Air Purifying Respirators in U.S. Healthcare" (PDF).
- ^ a b European Committee for Standardization (2005). "6 Verfahren zur Gefährdungsbeurteilung". In Technischen Komitee CEN/TC 79 "Respiratory protective devices" (ed.). DIN EN 529:2006 "Atemschutzgeräte - Empfehlungen für Auswahl, Einsatz, Pflege und Instandhaltung - Leitfaden" (in German) (Deutsche Fassung EN 529:2005 ed.). Brussels: Deutsche Gremium ist NA 027-02-04 AA «Atemgeräte für Arbeit und Rettung» im Normenausschuss Feinmechanik und Optik (NAFuO). p. 50.
- ^ a b c d e f "PPE Image Gallery: Respiratory Protective Equipment - Civilian - Radiation Emergency Medical Management". www.remm.nlm.gov.
- ^ a b File:Respirator Types.webm, time 8:19 (loose) and 8:43 (tight-fitting)
- ^ Brooks, Robyn. "Respiratory Safety: An Interview with Industry Experts -". Occupational Health & Safety Magazine.
- ^ a b Bollinger, Nancy (2004-10-01). "NIOSH respirator selection logic". U.S. National Institute for Occupational Safety and Health: 5–16. doi:10.26616/NIOSHPUB2005100. Retrieved 2020-04-20. For download on Wikimedia Commons: PDF fulltext
- ^ File:Sm90 zerlegt.png
- ^ Mean values for several models. For example, IDLH for CO2 = 4% Archived 20 April 2018 at the Wayback Machine, but filtering facepiese "AOSafety Pleats Plus" provided concentration up to 5.8%. According to the paper the model was discontinued from manufacturing and had its NIOSH approval withdrawn. (It is also no longer on the CEL, TC-84A-2630 and TC-84A-4320. Former approval by the FDA Archived 17 February 2017 at the Wayback Machine, while other discontinued models are still on the CEL Archived 14 July 2016 at the Wayback Machine) Source: E.J. Sinkule, J.B. Powell, F.L. Goss (2013). "Evaluation of N95 respirator use with a surgical mask cover: effects on breathing resistance and inhaled carbon dioxide". Annals of Occupational Hygiene. 57 (3). Oxford University Press: 384–398. doi:10.1093/annhyg/mes068. ISSN 2398-7308. PMID 23108786.
{{cite journal}}
: CS1 maint: multiple names: authors list (link) - ^ R.J. Roberge, A. Coca, W.J. Williams, J.B. Powell & A.J. Palmiero (2010). "Physiological Impact of the N95 Filtering Facepiece Respirator on Healthcare Workers". Respiratory Care. 55 (5). American Association for Respiratory Care (AARC): 569–577. ISSN 0020-1324. PMID 20420727. Archived from the original on 31 October 2020. Retrieved 28 February 2021.
{{cite journal}}
: CS1 maint: multiple names: authors list (link) - ^ Carmen L. Smith, Jane L. Whitelaw & Brian Davies (2013). "Carbon dioxide rebreathing in respiratory protective devices: influence of speech and work rate in full-face masks". Ergonomics. 56 (5). Taylor & Francis: 781–790. doi:10.1080/00140139.2013.777128. ISSN 0014-0139. PMID 23514282. S2CID 40238982. Archived from the original on 1 November 2020. Retrieved 28 February 2021.
- ^ Rhee, Michelle S. M.; Lindquist, Carin D.; Silvestrini, Matthew T.; Chan, Amanda C.; Ong, Jonathan J. Y.; Sharma, Vijay K. (2021). "Carbon dioxide increases with face masks but remains below short-term NIOSH limits". BMC Infectious Diseases. 21 (1): 354. doi:10.1186/s12879-021-06056-0. PMC 8049746. PMID 33858372.
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External links
[edit]- Jacobs, Andrew (2022-07-03). "A Clunky Mask May Be the Answer to Airborne Disease and N95 Waste". The New York Times. ISSN 0362-4331. Retrieved 2022-07-05.