Respirator canister with ESLI for asid gases -6

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 ...

cartridge or canister is a type of filter that removes gases,

volatile organic compound Volatile organic compounds (VOCs) are organic compounds that have a high vapour pressure at room temperature. High vapor pressure correlates with a low boiling point, which relates to the number of the sample's molecules in the surrounding air, a ...

s (VOCs), and other vapors from air through

adsorption 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 ...

, absorption, or

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 ...

. It is one of two basic types of filters used by

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. The other is a

mechanical filter A mechanical filter is a signal processing filter usually used in place of an electronic filter at radio frequencies. Its purpose is the same as that of a normal electronic filter: to pass a range of signal frequencies, but to block others. T ...

, which removes only

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

. Hybrid filters combine the two.

Workplace A workplace is a location where someone works, for their employer or themselves, a place of employment. Such a place can range from a home office to a large office building or factory. For industrialized societies, the workplace is one of th ...

air that is polluted with fine particulate matter or noxious gases but that contains enough oxygen (in the US, this is ruled to be a concentration above 19.5%; in the Russian Federation, above 18%), can be rendered safe via air-purifying respirators. Cartridges are of different types, and must be chosen correctly and replaced on an appropriate schedule.

Purification methods

Absorption

Capturing noxious gases may be accomplished by

sorbent A sorbent is a material used to absorb or adsorb liquids or gases. Examples include: *A material similar to molecular sieve material, which acts by adsorption (attracting molecules to its surface). It has a large internal surface area and good th ...

s. These materials ( activated carbon, ,

zeolite Zeolites are microporous, crystalline aluminosilicate materials commonly used as commercial adsorbents and catalysts. They mainly consist of silicon, aluminium, oxygen, and have the general formula ･y where is either a metal ion or H+. These p ...

, etc.) have a large

specific surface area Specific surface area (SSA) is a property of solids defined as the total surface area of a material per unit of mass, (with units of m2/kg or m2/g) or solid or bulk volume (units of m2/m3 or m−1). It is a physical value that can be used to dete ...

and can absorb many gases. Typically, such sorbents are in the form of granules, and fill the cartridge. Contaminated air travels through the cartridge's bed of sorbent granules. Movable harmful gas

molecule A molecule is a group of two or more atoms held together by attractive forces known as chemical bonds; depending on context, the term may or may not include ions which satisfy this criterion. In quantum physics, organic chemistry, and bioche ...

s collide with the surface of the sorbent and remain therein. The sorbent gradually saturates and loses its ability to capture pollutants. The bond strength between captured molecules and the sorbent is small, and molecules can separate from the sorbent and return to the air. The sorbent's ability to capture gases depends on the properties of the gases and their concentrations, including air

temperature Temperature is a physical quantity that expresses quantitatively the perceptions of hotness and coldness. Temperature is measurement, measured with a thermometer. Thermometers are calibrated in various Conversion of units of temperature, temp ...

and

relative humidity Humidity is the concentration of water vapor present in the air. Water vapor, the gaseous state of water, is generally invisible to the human eye. Humidity indicates the likelihood for precipitation, dew, or fog to be present. Humidity dep ...

.Conference listing
/ref>

Chemisorption

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 ...

utilizes a chemical reaction between the gas and the absorber. The ability of some harmful gases to react chemically with other substances can be used to capture them. Creating strong links between gas molecules and a sorbent may allow repeated use of a canister if it has enough unsaturated sorbent.

Copper Copper is a chemical element with the symbol Cu (from la, cuprum) and atomic number 29. It is a soft, malleable, and ductile metal with very high thermal and electrical conductivity. A freshly exposed surface of pure copper has a pinkis ...

salts, for example, can form complex compounds with ammonia. A mixture of copper ions (+2),

zinc carbonate Zinc carbonate is the inorganic compound with the formula ZnCO3. It is a white solid that is insoluble in water. It exists in nature as the mineral smithsonite. It is prepared by treating cold solutions of zinc sulfate with potassium bicarbonat ...

, and TEDA can detoxify hydrogen cyanide. By saturating activated carbon with chemicals, chemisorption can be used to help the material make stronger ties with molecules of trapped gases and improve the capture of harmful gases. Saturation of iodine improves mercury capture, saturation of metal

salts In chemistry, a salt is a chemical compound consisting of an ionic assembly of positively charged cations and negatively charged anions, which results in a compound with no net electric charge. A common example is table salt, with positively c ...

improves

ammonia Ammonia is an inorganic compound of nitrogen and hydrogen with the formula . A stable binary hydride, and the simplest pnictogen hydride, ammonia is a colourless gas with a distinct pungent smell. Biologically, it is a common nitrogenous wa ...

capture, and saturation of metal oxides improves

acid gas Acid gas is a particular typology of natural gas or any other gas mixture containing significant quantities of hydrogen sulfide (H2S), carbon dioxide (CO2), or similar acidic gases. A gas is determined to be acidic or not after it is mixed with w ...

capture.

Catalytic decomposition

Some harmful gases can be neutralized through

catalytic oxidation Catalytic oxidation are processes that rely on catalysts to introduce oxygen into organic and inorganic compounds. Many applications, including the focus of this article, involve oxidation by oxygen. Such processes are conducted on a large scale ...

. A

hopcalite Hopcalite is the trade name for a number of mixtures that mainly consist of oxides of copper and manganese, which are used as catalysts for the conversion of carbon monoxide to carbon dioxide when exposed to the oxygen in the air at room temperatu ...

can oxidize toxic

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 ...

(CO) into harmless

carbon dioxide Carbon dioxide ( chemical formula ) is a chemical compound made up of molecules that each have one carbon atom covalently double bonded to two oxygen atoms. It is found in the gas state at room temperature. In the air, carbon dioxide is trans ...

(CO₂). The effectiveness of this

catalyst Catalysis () is the process of increasing the rate of a chemical reaction by adding a substance known as a catalyst (). Catalysts are not consumed in the reaction and remain unchanged after it. If the reaction is rapid and the catalyst recyc ...

strongly decreases as

increases. Therefore, desiccants are often added. Air always contains

water vapor (99.9839 °C) , - , Boiling point , , - , specific gas constant , 461.5 J/( kg·K) , - , Heat of vaporization , 2.27 MJ/kg , - , Heat capacity , 1.864 kJ/(kg·K) Water vapor, water vapour or aqueous vapor is the gaseous p ...

, and after saturation of the desiccant, the catalyst ceases to function.

Combined cartridges

Combined, or multi-gas cartridges protect from harmful gases by using multiple sorbents or catalysts. An example is ''ASZM-TEDA Carbon'' used in

CBRN Chemical, biological, radiological and nuclear defence (CBRN defence) are protective measures taken in situations in which chemical, biological, radiological or nuclear warfare (including terrorism) hazards may be present. CBRN defence consi ...

masks by the

US Army The United States Army (USA) is the land service branch of the United States Armed Forces. It is one of the eight U.S. uniformed services, and is designated as the Army of the United States in the U.S. Constitution.Article II, section 2, cla ...

. This is a form of activated carbon 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).

Classification and marking

Cartridge selection comes after assessing the atmosphere. NIOSH guides cartridge choice in the US along with manufacturer recommendations.

United States

In the US, approval for respirator cartridge particulate filtration efficiency classification and certification is administered by the

National Institute for Occupational Safety and Health The National Institute for Occupational Safety and Health (NIOSH, ) is the United States federal agency responsible for conducting research and making recommendations for the prevention of work-related injury and illness. NIOSH is part of the C ...

(NIOSH) as part of Part 84 of Title 42 of the Code of Federal Regulations (42 CFR 84). Manufacturers can certify cartridges intended for purifying workplace air from various gaseous contaminants.

Orange can be used for painting the entire cartridge housing, or as a strip. But this color is not in the table, and determining the cartridge's protection requires reading the inscription. Legislation requires the employer to select cartridges using only labels (not color markings).

European Union and Russia

In the

European Union The European Union (EU) is a supranational political and economic union of member states that are located primarily in Europe. The union has a total area of and an estimated total population of about 447million. The EU has often been de ...

(EU) and the

Russian Federation Russia (, , ), or the Russian Federation, is a transcontinental country spanning Eastern Europe and Northern Asia. It is the largest country in the world, with its internationally recognised territory covering , and encompassing one-eig ...

(RF), manufacturers can certify cartridges intended for cleaning the air of various gaseous contaminants. The codes are covered by EN14387, additionally particulate codes P1, P2 and P3 are used. For example, A1P2 is the code for commonly used filters in industry and agriculture that provide protection against A-type gases and commonly occurring particulates.

Cartridges AX, SX, and NO not distinguish on the sorption capacity (as in the US) when they are classified and certified. If the cartridge is designed to protect from several different types of harmful gases, the label will list all designations in order. For example: A2B1, color - brown and grey. Other jurisdictions that use this style of classification include Australia/New Zealand (AS/NZS 1716:2012) and China (GB 2890:2009).

Detection of end of service life

Service lives of all types of cartridges are limited, therefore, the employer is obliged to replace them in a timely manner.

Old methods

Subjective reactions of users' sensory systems

The use of cartridges in the contaminated atmosphere leads to saturation of the sorbent (or the dryer — when using catalysts). The concentration of harmful gases in the purified air gradually increases. The ingress of harmful gases in the inhaled air can lead to a reaction in a user's

sensory system The sensory nervous system is a part of the nervous system responsible for processing sensory information. A sensory system consists of sensory neurons (including the sensory receptor cells), neural pathways, and parts of the brain involved i ...

: odor,

taste The gustatory system or sense of taste is the sensory system that is partially responsible for the perception of taste (flavor). Taste is the perception produced or stimulated when a substance in the mouth reacts chemically with taste receptor ...

, irritation of the

respiratory system The respiratory system (also respiratory apparatus, ventilatory system) is a biological system consisting of specific organs and structures used for gas exchange in animals and plants. The anatomy and physiology that make this happen varies ...

dizziness Dizziness is an imprecise term that can refer to a sense of disorientation in space, vertigo, or lightheadedness. It can also refer to disequilibrium or a non-specific feeling, such as giddiness or foolishness. Dizziness is a common medical c ...

headaches Headache is the symptom of pain in the face, head, or neck. It can occur as a migraine, tension-type headache, or cluster headache. There is an increased risk of depression in those with severe headaches. Headaches can occur as a result ...

, and other health impairments up to the loss of

consciousness Consciousness, at its simplest, is sentience and awareness of internal and external existence. However, the lack of definitions has led to millennia of analyses, explanations and debates by philosophers, theologians, linguisticians, and scien ...

. These signs (known in the US as "warning properties" - p. 28) indicate that one must leave the polluted workplace area, and replace the cartridge with a new one. This can also be a symptom of a loose fit the mask to one's

face The face is the front of an animal's head that features the eyes, nose and mouth, and through which animals express many of their emotions. The face is crucial for human identity, and damage such as scarring or developmental deformities may aff ...

and the leakage of unfiltered air through the gaps between the mask and the face. Historically, this method is the oldest. ESLI-after-Hg-exposure

The advantages of this method – if harmful gases have warning properties at concentrations less than 1 PEL, the replacement will be produced on time (''in most cases, at least''); the application of this method does not require the use of special cartridges (more expensive) and accessories; replacement happens when one needs to do it – after the sorbent saturation, and without any calculations; the sorption capacity of the cartridges is fully expired (which reduces costs for respiratory protection). The disadvantage of this method is that some harmful gases have no warning properties. For example, there is a list of over 500 harmful gases in the Respirator Selection Guide and over 60 of them have no warning properties, and there is no such information for over 100 of them. So, if one uses warning properties to replace cartridges, this may lead to breathing air with an excess harmful gas concentration in some cases. The table contains a list of the chemicals that have no warning properties. If the threshold odor of pentaborane is 194 PEL; and if its concentration is only 10 PEL, one cannot timely change cartridges by using smell - they could be "used" forever'', but they cannot protect forever.'' The practice has shown that the presence of warning properties does not always lead to timely cartridge replacement. A study showed that on average 95% of a group of people have an individual threshold of olfactory sensitivity in the range of from 1/16 to 16 from the mean. This means that 2.5% of people will not be able to smell harmful gases at a concentration 16 times greater than the average threshold of perception of a smell. The threshold of sensitivity of different people can vary by two orders of magnitude. That is, 15% of people do not smell at concentrations four times higher than the sensitivity threshold. The value of threshold smell greatly depends on how much attention people pay to it, and on their health status. The sensitivity may be reduced, for example, due to

colds The common cold or the cold is a viral infectious disease of the upper respiratory tract that primarily affects the respiratory mucosa of the nose, throat, sinuses, and larynx. Signs and symptoms may appear fewer than two days after exposu ...

and other ailments. It turns out that a worker's ability to detect smell also depends on the nature of the work to be performed—if it requires concentration, a user may not react to the smell. Prolonged exposure to harmful gases (for example, hydrogen sulfide) at low concentrations can create

olfactory fatigue Olfactory fatigue, also known as odor fatigue, olfactory adaptation, and noseblindness, is the temporary, normal inability to distinguish a particular odor after a prolonged exposure to that airborne compound. For example, when entering a restaur ...

which reduces sensitivity. In all of these cases, users can be exposed to harmful substances with concentrations larger than 1 PEL, and it may lead to the development of

occupational disease An occupational disease is any chronic ailment that occurs as a result of work or occupational activity. It is an aspect of occupational safety and health. An occupational disease is typically identified when it is shown that it is more prevale ...

s. This was the reason for the ban to use this method of cartridge replacement in the US since 1996 (the Occupational Safety and Health Administration OSHA standard).

Mass increase

To protect workers from carbon monoxide cartridges often use the catalyst

. This catalyst does not change its properties over time of use, but when it moistened, the degree of protection may be significantly reduced. Because water vapor is always present in the air, the polluted air is dehumidified in the cartridge (for use of the catalyst). Since the mass of water vapor in the polluted air is greater than the mass of harmful gases, trapping moisture from the air leads to a significantly higher increase in the mass of cartridges than the trapping gases. This is a substantial difference, and it can be used to determine whether to continue to use gas cartridges further without replacement. The cartridge is weighed, and a decision can be made based on the magnitude of increase of its mass. For example, the book describes gas cartridges (model "СО"), which were replaced after a weight gain (relative to initial) of 50 grams.

Other methods

The documents described Soviet cartridges (model "Г"), designed to protect from mercury. Their service life was limited to 100 hours of use (cartridges without particle filter), or 60 hours of use (cartridges with particle filter), after which it was necessary to replace the cartridge with a new one. The documents describe a non-destructive way to determine the remaining service life of new and used gas cartridges. Polluted air was pumped through the cartridge. The degree of purification of air depends on how much-unsaturated sorbent is in the cartridge, therefore, accurate measurement of gas concentration in the cleaned air allows one to estimate the amount of the unsaturated sorbent. Polluted air (

1-bromobutane 1-Bromobutane is the organobromine compound with the formula CH3(CH2)3Br. It is a colorless liquid, although impure samples appear yellowish. It is insoluble in water, but soluble in organic solvents. It is a primarily used as a source of the buty ...

) was pumped for a very short time, and therefore, such tests do not reduce the service life considerably. The sorption capacity decreased due to absorption of this gas by about 0.5% of the sorption capacity of a new cartridge. The method was also used for 100% quality control of the cartridges manufactured by the English firm Martindale Protection Co. (10 microliters 1-bromobutane injected into the air stream), and to check the cartridges issued to workers in firms Waring, Ltd. and Rentokil, Ltd. This method was used in the Chemical Defence Establishment in the early 1970s. The experts who developed this method, received a

patent A patent is a type of intellectual property that gives its owner the legal right to exclude others from making, using, or selling an invention for a limited period of time in exchange for publishing an enabling disclosure of the invention."A ...

. The document briefly describes two methods to objectively evaluate the degree of saturation of the sorbent in the cartridges. It recommends using spectral and microchemical methods. The spectral method is based on determining the presence of harmful substances in the cartridge by sampling, with subsequent analysis on a special device (стилоскоп - ''on Russian''). A microchemical method is based on a layer-by-layer determination of the presence of harmful substances in the sorbent by sampling with subsequent analysis by chemical method. If the air is contaminated with the most toxic substances, the book recommends to limit the further duration of cartridge use, and it recommended to apply the spectral method (

arsine Arsine (IUPAC name: arsane) is an inorganic compound with the formula As H3. This flammable, pyrophoric, and highly toxic pnictogen hydride gas is one of the simplest compounds of arsenic. Despite its lethality, it finds some applications in ...

and

phosphine Phosphine (IUPAC name: phosphane) is a colorless, flammable, highly toxic compound with the chemical formula , classed as a pnictogen hydride. Pure phosphine is odorless, but technical grade samples have a highly unpleasant odor like rotting ...

, phosgene, fluorine,

organochloride An organochloride, organochlorine compound, chlorocarbon, or chlorinated hydrocarbon is an organic compound containing at least one covalently bonded atom of chlorine. The chloroalkane class (alkanes with one or more hydrogens substituted by chlo ...

organometallic compounds Organometallic chemistry is the study of organometallic compounds, chemical compounds containing at least one chemical bond between a carbon atom of an organic molecule and a metal, including alkali, alkaline earth, and transition metals, and so ...

), and microchemical methods ( hydrogen cyanide,

cyanogen Cyanogen is the chemical compound with the formula ( C N)2. It is a colorless and highly toxic gas with a pungent odor. The molecule is a pseudohalogen. Cyanogen molecules consist of two CN groups – analogous to diatomic halogen molecu ...

s). Unfortunately, in both cases, there is no description of how to extract a sample of the sorbent from the cartridge housing (the housing is usually not detachable), and use the cartridge after this test, if the test shows that it does not have a lot of saturated sorbents.

Modern methods

Cartridge certification provides a minimum value of their sorption capacity. US

OSHA OSHA or Osha may refer to: Work * Occupational Safety and Health Administration, a federal agency of the United States that regulates workplace safety and health * Occupational Safety and Health Act (United States) of 1970, a federal law in the Un ...

standard for

1,3-Butadiene 1,3-Butadiene () is the organic compound with the formula (CH2=CH)2. It is a colorless gas that is easily condensed to a liquid. It is important industrially as a precursor to synthetic rubber. The molecule can be viewed as the union of two vi ...

indicates the specific service life of the cartridges.

Laboratory testing

If the company has a

laboratory A laboratory (; ; colloquially lab) is a facility that provides controlled conditions in which scientific or technological research, experiments, and measurement may be performed. Laboratory services are provided in a variety of settings: physic ...

with the right equipment, specialists can skip the contaminated air through the cartridge and determine the degree of cleaning needed. This method enables one to determine the service life in an environment where the air is contaminated with a mixture of different substances that affect their capture with a sorbent (one affecting another capture). Service life calculation methods for such conditions have been developed relatively recently. However, this requires accurate information on concentrations of noxious substances, and they often are not permanent. Tests in laboratories can identify the balance of service life of cartridges after their use. If the remainder is large, similar cartridges in such circumstances can be used over a longer period of time. In some cases, a large balance allows the use of cartridges repeatedly. This method does not require accurate information on the concentrations of harmful substances. The cartridge replacement schedule is drawn upon the basis of the results of their testing in the laboratory. This method has a serious drawback. The company must have complex and expensive equipment and trained professionals to use it, which is not always possible. According to a poll, cartridges replacement in the US was carried out on the basis of laboratory tests in approximately 5% of all organizations. Research to determine whether it is possible to calculate the service life of respirator cartridges (if one know the conditions of their use) have been conducted in developed countries since the 1970s. This allows one to replace cartridges in a timely fashion without the use of sophisticated and expensive equipment.

Computer programs

The world's leading respirator manufacturers offered customers

computer program A computer program is a sequence or set of instructions in a programming language for a computer to execute. Computer programs are one component of software, which also includes documentation and other intangible components. A computer program ...

s for calculating the service life already in the year 2000.

3M program allowed to calculate the service life of the cartridges exposed with more than 900 harmful gases and their combinations in 2013. The MSA program enables taking into account hundreds of gases and their combinations. The same program was developed by Scott and Dragerwerk. J. Wood developed a mathematical model and software which now allows one to calculate the service life of any cartridges with known properties. Now OSHA uses it in its Advisor Genius program. The merit of this way of replacing the cartridges is that it allows an employer to use normal, "common" cartridges, and if they have the exact data, they may replace them in time. The downside is that because of air contamination is often not constant, and the nature of the work to be performed is not always stable (that is, the flow of air through the cartridges is not permanent), it is recommended to use working conditions for calculations, equal to the worst case, for reliable protection. But in all other cases, cartridges will be replaced with a partially used sorbent. This increases the costs of respiratory protection due to more frequent cartridges replacement. In addition, calculation accuracy is reduced under very high

, because the mathematical model does not take into account some of the physical effects in such cases.

End-of-service-life indicators

If a cartridge has a device to warn the user of the approaching expiration of the service life (end-of-service-life indicator, ESLI), the indication can be used for timely replacement of cartridges. ESLI can be active or passive. A passive indicator often uses a sensor that changes color. This element is installed in the cartridge at some distance from the filtered air outlet so that the color change occurs before harmful gases begin to pass through the cartridge. An active indicator may use a light or an audible alarm to signal that a cartridge needs to be replaced. Passive end-of-service-life indicators ESLI-1925.jpg , Yablick 1925 Индикатор для определения срока службы фильтра End of Service Life Indicator ESLI 05.jpg , ChemMotif 2000 Индикатор для определения срока службы фильтра End of Service Life Indicator ESLI 12.jpg , THO 1998 & Linders Индикатор для определения срока службы фильтра End of Service Life Indicator ESLI 14.jpg , ТНО 2004 Индикатор для определения срока службы фильтра End of Service Life Indicator ESLI 06.jpg , Dragerwerk 1986 Индикатор для определения срока службы фильтра End of Service Life Indicator ESLI 15.jpg , Wallace 1975 Индикатор для определения срока службы фильтра End of Service Life Indicator ESLI 16.jpg , Wallace 1975 Индикатор для определения срока службы фильтра End of Service Life Indicator ESLI 17.jpg , Roberts 1976 Индикатор для определения срока службы фильтра End of Service Life Indicator ESLI 18.jpg , China 2001 Индикатор для определения срока службы фильтра End of Service Life Indicator ESLI 19.jpg , Dragerwerk 1957 Active indicators use light or an audible alarm for user notification that is triggered by a sensor that is usually installed in the cartridge. Such indicators allow one to replace the cartridges on time in any light and do not require the worker to pay attention to the color of the indicator. They can also be used by workers who badly distinguish different colors. Active-ESLI

Despite the presence of solutions for technical problems, and the availability of established certification requirements to the ESLI, during the period from 1984 (first certification standard with requirements for active ESLI) until 2013 not one cartridge with active ESLI was approved in the US. It turned out that the requirements for the cartridges are not quite exact, and employers are under no requirement to use these indicators specifically. Therefore, respirator manufacturers fear

commercial failure Failure is the state or condition of not meeting a desirable or intended objective, and may be viewed as the opposite of success. The criteria for failure depends on context, and may be relative to a particular observer or belief system. One ...

when selling new unusual products, although they continue to carry out research and development work in this area. Active end-of-service-life indicators: Индикатор для определения срока службы фильтра End of Service Life Indicator ESLI.jpg , American Optical Индикатор для определения срока службы фильтра End of Service Life Indicator ESLI 02.jpg , Auergesellschaft 1989 Индикатор для определения срока службы фильтра End of Service Life Indicator ESLI 03.jpg , Auergesellschaft 1989 Индикатор для определения срока службы фильтра End of Service Life Indicator ESLI 04.jpg , Bernard 1998 Индикатор для определения срока службы фильтра End of Service Life Indicator ESLI 07.jpg , Dragerwerk 1994 Индикатор для определения срока службы фильтра End of Service Life Indicator ESLI 08.jpg , FOGS 1998 Индикатор для определения срока службы фильтра End of Service Life Indicator ESLI 09.jpg , Geraetebau 1991 Индикатор для определения срока службы фильтра End of Service Life Indicator ESLI 10.jpg , Shigematsu 2002 Индикатор для определения срока службы фильтра End of Service Life Indicator ESLI 11.jpg , Stetter 1991 ESLI 6051i 1-4

Examination of respirator use in the US showed that over 200,000 workers may be exposed to excessive harmful gases due to late replacement of cartridges. So, the Laboratory of PPE ( NPPTL) at the NIOSH began to develop an active ESLI. After the completion of the work, its results will help establish clear legal requirements for employers to follow and resulting technology will be transferred to industry to use in new improved RPD.

Legal requirements

Since it is not always possible to replace cartridges in a timely manner through the use of their odor ets,

has banned the use of this method. The employer is obliged to use only two ways to replace cartridges: on schedule, and by using ESLI (because only these methods provide reliable preservation of workers’ health). OSHA instructions to inspectors provides specific guidance on inspection of implementation of such requirements. On the other hand, the state requires manufacturers to provide the consumer with all necessary information about cartridges to allow one to make a schedule for their timely replacement. Similar requirements exist in the standard on occupational safety, governing selection and application of RPD in EU. In England a tutorial on the selection and use of respirators recommends obtaining information from the manufacturer, and replacing the cartridges on a schedule or use ESLI, and prohibits reusing cartridges after exposure of volatile substances that can migrate. * The US law required the employer to use exceptionally supplied air RPD (SAR) for protection against harmful gases that have no warning properties. The use of supplied air respirators may be the only way to reliably protect workers in circumstances when there is no ESLI, and it is impossible to calculate their service life. * Legislation in the EU allows an employer to use only supplied air respirators when employees work in conditions where air pollution is

IDLH 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 ...

, because of the risk of untimely cartridge replacement. Respirator canister with ESLI for asid gases -9

Reuse

If the cartridge contains a lot of the sorbent and if the concentration of contaminants is low; or if the cartridge was used for a short duration of time, after completion of its use, it still has a lot of unsaturated sorbent (which can capture gases). This may allow using such cartridges again. The molecules of an entrapped gases may de-absorb during storage of the cartridge. Due to the difference of concentrations inside the body of the cartridge (at the inlet concentration is greater; at the outlet for purified air concentration is lesser), these de-absorbed molecules migrate inside the cartridge to the outlet. The study of cartridges exposed to methyl bromide showed that this migration can impede the re-use of storage. Concentration of harmful substances in the purified air may exceed the PEL (even if clean air is pumped through the cartridge). To protect worker health, US law prohibits cartridge reuse when exposed to harmful substances that can migrate, even if the cartridge has much non-saturated sorbent after the first use. According to the standards, "volatile" substances (those able to migrate) are considered substances with a boiling point below 65 °C. But studies have shown that at the boiling point above 65 °C reuse of the cartridge may be unsafe. Therefore, the manufacturer must provide the buyer with all information required for safe cartridge use. So, if the period of continuous service life of the cartridge (calculated by the program - see above) exceeds eight hours (see tables 4 and 5), the legislation may limit their use to one shift. The paper provides a procedure for calculating the concentration of harmful substances in purified air at the start of cartridge reuse which allows one to determine exactly where they may be safely reused. But these scientific results are not yet reflected in any standards or guidelines on respirator use. The author of the article, working in the US, did not even try to consider the use of gas cartridges more than twice. On the author's website one can download a free computer program that allows one to calculate concentration of harmful substances immediately after the start of re-use of the cartridge (which allows one to determine if it is safe).

Regenerating gas cartridges

Activated carbon does not bond with harmful gases strongly, so they can be released later. Other sorbents undergo chemical reactions with the hazard and form strong bonds. Special technologies have been developed for recovery of used cartridges. They created conditions that have stimulated desorption caught earlier harmful substances. This used steam or heated air in the 1930s or other methods. Processing of the sorbent was carried out after its removal from the body of the cartridge, or without removing. Specialists tried to use

ion-exchange resin An ion-exchange resin or ion-exchange polymer is a resin or polymer that acts as a medium for ion exchange. It is an insoluble matrix (or support structure) normally in the form of small (0.25–1.43 mm radius) microbeads, usually white or ye ...

as the absorber in 1967. The authors proposed to regenerate the sorbent by washing it in a solution of alkali or soda. The study also showed that cartridges can be effectively regenerated after exposure to methyl bromide (when they are blown with hot air 100 to 110 °C, flow rate 20 L/min, duration about 60 minutes). Regeneration of sorbents is used consistently and systematically in the chemical industry, as it allows cost savings on the replacement of sorbent and regeneration of industrial gas cleaning devices to be carried out thoroughly and in an organized manner. However, in the mass use of gas masks under different conditions it is impossible to control the accuracy and correctness such regeneration of respirators’ cartridges. Therefore, despite the technical feasibility and commercial benefits, regeneration of respirator cartridges in such cases is not carried out.

References

{{reflist, refs= {{cite book, last1=Дубинин , first1= Михаил, last2=Чмутов К., title=Физико-химические основы противогазного дела // ''Physico-chemical bases of development and application of gas masks'' , year=1939, publisher=Военная академия химической защиты имени К.Е. Ворошилова, location=Moscow, language=ru .{{cite book , last1=David S. DeCamp, Joseph Costantino, Jon E. Black , title=Estimating Organic Vapor Cartridge Service Life , date=November 2004 , publisher=Air Force Institute for Operational Health Risk Analysis Directorate , location=Kennedy Circle Brooks City-Base , pages=53 , url=https://apps.dtic.mil/dtic/tr/fulltext/u2/a439710.pdf , archive-url=https://web.archive.org/web/20191005161425/https://apps.dtic.mil/dtic/tr/fulltext/u2/a439710.pdf , url-status=live , archive-date=October 5, 2019 , access-date=9 November 2019 , language=en {{Cite web, url=https://www.osha.gov/SLTC/etools/respiratory/change_schedule.html, title=Respirator Change Schedules ''(Respiratory Protection eTool)'', author=Occupational Safety and Health Administration, website=www.osha.gov, date=2019, location=200 Constitution Ave NW Washington, DC 20210, language=en, access-date=2019-12-08 {{cite book, last1=Bollinger, first1=Nancy , title=NIOSH Respirator Selection Logic, url=https://www.cdc.gov/niosh/docs/2005-100/, series=NIOSH-Issued Publications, date=October 2004, publisher=National Institute for Occupational Safety and Health, location=Cincinnati, OH , display-authors=etal, doi=10.26616/NIOSHPUB2005100 {{cite book, title=2008 Respirator Selection Guide, year=2008, publisher=3M, location=St. Paul, MN, pages=15–96 {{cite book, last1=Bollinger, first1=Nancy, last2=Schutz, first2=Robert, title=A Guide to Industrial Respiratory Protection, url=https://www.cdc.gov/niosh/docs/87-116/, series=NIOSH-Issued Publications, year=1987, publisher=National Institute for Occupational Safety and Health, location=Cincinnati, OH , display-authors=etal, doi=10.26616/NIOSHPUB87116 {{cite journal, last=Amoore, first=John, author2=Hautala Earl, year=1983, title=Odor as an aid to chemical safety: odor thresholds compared with threshold limit values and volatilities for 214 industrial chemicals in air and water dilution, journal=Journal of Applied Toxicology, volume=3, issue=6, pages=272–290, issn=1099-1263, doi=10.1002/jat.2550030603, pmid=6376602, s2cid=36525625 US OSHA occupational health and safety standard 29 Code of Federal Register 1910.1051 1,3-Butadien
''1910.1051(h)(3) Respirator selection''
/ref> {{cite book, last=U.S. Department of Labor, Bureau of Labor Statistics, title=Respirator Usage in Private Sector Firms, url=https://www.cdc.gov/niosh/docs/respsurv/pdfs/respsurv2001.pdf, year=2003, publisher=U.S. Department of Health and Human Services, Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health, location=Morgantown, WV, pages=214 (table 91) {{cite book, last1=ZieglerG. , first1= Martin , last2=Hauthal W. , last3=Koser H. , title=Entwicklung von Indikatoren zur Anzeige des Gebrauchsdauer-Endes von Gasfiltern (Machbarkeitsstudie), edition=1, series=Forschung Fb 997, year=2003, publisher=Wirtschaftsverl, location=Bremerhaven, language=de, isbn=978-3-86509-041-6 {{cite journal, last=Cothran T., year=2000, title=Features - Service Life Software for Organic Vapour Cartridges, journal=Occupational Health and Safety, volume=69, issue=5, pages=84–93, issn=0362-4064 The link to the document describing the progra
MerlinTM
{{Webarchive, url=https://web.archive.org/web/20160304063250/http://www.aearo.com/pdf/CHANGE.pdf , date=2016-03-04 . Unfortunately, the product could not be found. Old link
Program for Cartridge Service Life calculation ezGuide
/ref> Link to the manufacturer's website where You can download a program to calculate the life of the cartridges
S-Series - Software Downloads
an
T-Series - Software Downloads

until January 1, 2016. MSA program Cartridge Life Calculato
link 1link 2
(for US) Link to a databas
VOICE
developed by Drager (''version for US'') with the program for calculation cartridge service life ''End-of-ServiceLife Calculator'' The program for calculation of service life of respirator cartridges that use a mathematical model of Jerry Wood

/ref> The program for calculation of service life of respirator cartridges, developed by Scott
SureLife™ Cartridge Calculator
{{Webarchive, url=https://web.archive.org/web/20090608165352/http://www.scottsurelife.com/DesktopUI/Login.aspx?RegionId=MQ

-PMHQ7K9J3Kg= , date=2009-06-08 US NIOSH occupational safety and health standard 42 Code of Federal Register 84 Approval of Respiratory Protective Device
‘’84.255 Requirements for end-of-service-life indicator.‘’
/ref> {{cite book, last=Favas, first=George , title=End of Service Life Indicator (ESLI) for Respirator Cartridges. Part I: Literature Review, url=http://www.dtic.mil/cgi-bin/GetTRDoc?Location=U2&doc=GetTRDoc.pdf&AD=ADA446250, archive-url=https://web.archive.org/web/20130502032450/http://www.dtic.mil/cgi-bin/GetTRDoc?Location=U2&doc=GetTRDoc.pdf&AD=ADA446250, url-status=dead, archive-date=May 2, 2013, date=July 2005, publisher=Human Protection & Performance Division, Defence Science and Technology Organisation, location=Victoria 3207 Australia, page=49 Computer progra

- Immediate Breakthrough Upon Reuse BS 4275:1997 Guide to implementing an effective respiratory protective device programme DIN EN 529:2006. Atemschutzgerate - Empfehlungen fur Auswahl, Einsatz, Pflege und Instandhaltung. US OSHA occupational safety and health standard 29 Code of Federal Register 1910.13
Respiratory Protection
/ref> Charles Jeffress (OSHA
Instruction CPL 2-0.120
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Sensor Development for ESLI & Application to Chemical Detection
/ref> {{cite book, last=Myers, first=Warren, editor=Donald Miller, title=NIOSH Respirator Decision Logic, chapter-url=https://www.cdc.gov/niosh/docs/87-108/, series=DHHS (NIOSH) Publication No. 87-108, year=1987, publisher=National Institute for Occupational Safety and Health, location=Cincinnati, Ohio, pages=48–50, chapter=Appendice C. Odor warning: Background information., display-authors=etal {{cite book, last1=Clayton G.D., last2=Clayton E.F, title=Patty's Industrial Hygiene and Toxicology, edition=3, volume=1, year=1985, publisher=Willey-Interscience, location=New York, isbn=978-0-471-01280-1, page=1008 42 Code of Federal Register 84 Approval of respiratory protective device
§84.113 — Canisters and cartridges; color and markings; requirements
{{Webarchive, url=https://web.archive.org/web/20160312111808/http://cfr.regstoday.com/42cfr84.aspx#42_CFR_84p113 , date=2016-03-12 {{cite book, last=Rosenstock, first=Linda , title=TB Respiratory Protection Program In Health Care Facilities, chapter-url=https://www.cdc.gov/niosh/docs/99-143/, series=DHHS (NIOSH) Publication No. 99-143, year=1999, publisher=National Institute for Occupational Safety and Health, location=Cincinnati, Ohio, pages=42–44, chapter=Appendix A, display-authors=etal RF state standard ГОСТ �
12.4.193-99
{{Webarchive, url=https://web.archive.org/web/20150630031338/http://www.ohranatruda.ru/ot_biblio/gost/6976.php?sphrase_id=1681487 , date=2015-06-30 Occupational safety standards system. Respiratory protective devices. Gas filters and combined filters. General specifications (''on Russian'') RF state standard ГОСТ �
12.4.231-2007
{{Webarchive, url=https://web.archive.org/web/20150630043316/http://www.ohranatruda.ru/ot_biblio/gost/680.php?sphrase_id=1681114 , date=2015-06-30 Occupational safety standards system. Respiratory protective devices. АX gas filters and combined filters for protection against low-boiling organic compounds. General specifications (''on Russian'') RF state standard ГОСТ �
12.4.232-2007
{{Webarchive, url=https://web.archive.org/web/20150630042537/http://ohranatruda.ru/ot_biblio/gost/1172.php?sphrase_id=4581064 , date=2015-06-30 Occupational safety standards system. Respiratory protective devices. SX gas filters and combined filters for protection against specific named compounds. General specifications (''on Russian'') RF state standard ГОС�
12.4.235-2012
(EN 14387:2008) Occupational safety standards system. Respiratory protective devices. Gas filters and combined filters. General technical requirements. Test methods. Marking (''on Russian'') RF state standard ГОС�
12.4.245-2013
Occupational safety standards system. Respiratory protective devices. Gas filters and combined filters. General specifications (''on Russian'') {{cite book, editor=Michael E. Barsan, title= NIOSH Pocket guide to chemical hazards, url=https://www.cdc.gov/niosh/docs/2005-149/, edition=3, series=DHHS (NIOSH) Publication No. 2005-149, year=2007, publisher=National Institute for Occupational Safety and Health, location=Cincinnati, Ohio, pages=xiv–xvi; xx–xxiii; 2–340 {{cite journal, last=Wood, first=Gerry, author2=Jay Snyder, year=2007, title=Estimating Service Lives of Organic Vapor Cartridges III: Multiple Vapors at All Humidities, journal=Journal of Occupational and Environmental Hygiene, volume=4, issue=5, pages=363–374, issn=1545-9632, doi=10.1080/15459620701277468, pmid=17454504, s2cid=12914878 , url=https://zenodo.org/record/1234513 {{cite journal, last1=Maggs, first1=F. A. P., last2=Smith, first2=M. E., title=The Use and Regeneration of Type-O Canisters for Protection Against Methyl Bromide, journal=Annals of Occupational Hygiene, volume=18, issue=2, year=1975, pages=111–119, issn=0003-4878, doi=10.1093/annhyg/18.2.111, pmid=1059379 {{cite journal, last1=Wood, first1=Gerry O., last2=Snyder, first2=Jay L., title=Estimating Reusability of Organic Air-Purifying Respirator Cartridges, journal=Journal of Occupational and Environmental Hygiene, volume=8, issue=10, year=2011, pages=609–617, issn=1545-9624, doi=10.1080/15459624.2011.606536, pmid=21936700, s2cid=40470245 {{cite book, last1=Трумпайц Я.И., last2=Афанасьева Е.Н., title=Индивидуальные средства защиты органов дыхания (альбом) // ''Respiratory Protective Devices (album-catalogue)'' , year=1962 , publisher=Профиздат , location=Leningrad , language=ru {{cite book, last1=Шкрабо М.Л., title=Промышленные противогазы и респираторы. Каталог. // ''Industrial Respiratory Protective Devices. Catalogue.'' , year=1982, publisher=Отделение НИИТЭХИМа, location= Cherkassy, language=ru, display-authors=etal {{cite book, last1=Ballantyne , first1=Bryan, last2=Schwabe , first2=Paul, title=Respiratory Protection. Principles and Applications, year=1981, publisher=Chapman & Hall, location=London, New York, language=en, isbn=978-0412227509, display-authors=etal {{cite journal, last=Maggs F.A.P, year=1972, title=A Non-destructive Test of Vapour Filters, journal=The Annual of Occupational Hygiene, volume=15, issue=2–4, pages=351–359, issn=1475-3162, doi=10.1093/annhyg/15.2-4.351, pmid=4648247, language=en British Patent No 60224/69 {{cite book, last1=Тихова Т.С., editor=Капцов В.А., title=Средства индивидуальной защиты работающих на железнодорожном транспорте. Каталог-справочник // ''Personal protective equipment for railway workers. Сatalogue-guidebook'' , publisher=ВНИИЖГ, Транспорт, location=Moscow, page=245, language=ru, display-authors=etal {{cite book, last=Торопов, first=Сергей, title=Испытания промышленных фильтрующих противогазов // The testing of industrial air purifying respirators , year=1938, publisher=Государственное научно-техническое издательство технической литературы НКТП. Редакция химической литературы , location=Moscow, language=ru {{cite book, last=Торопов, first=Сергей, title=Промышленные противогазы и респираторы // Industrial gas masks and respirators , year=1940, publisher=Государственное научно-техническое издательство технической литературы, location=Moscow Leningrad, language=ru {{cite journal, last=Руфф ВТ, year=1936, title=Регенерация промышленных фильтрующих противогазов // ''Regeneration of cartridges from industrial RPD'', journal=Гигиена труда и техника безопасности // Occupational Health and Safety , issue=1, pages=56–60, language=ru {{cite journal, author1=Вулих А.И. , author2=Богатырёв В.Л. , author3=Загорская М.К. , author4=Шивандронов Ю.А. , year=1967, title=Иониты в качестве поглотителей для противогазов // ''The ion exchangers as a sorbent for respirator cartridges'' , journal=Безопасность труда в промышленности // Occupational Safety in Industry , issue=1, pages=46–48, issn=0409-2961, language=ru {{cite book, last1=Rose-Pehrsson, first1=Susan L., last2=Williams, first2=Monica L., title=Integration of Sensor Technologies into Respirator Vapor Cartridges as End-of-Service-Life Indicators: Literature and Manufacturer's Review and Research Roadmap, url=http://oai.dtic.mil/oai/oai?verb=getRecord&metadataPrefix=html&identifier=ADA434905, year=2005, publisher=US Naval Research Laboratory, location=Washington, DC, page=37, access-date=2015-06-27, archive-url=https://web.archive.org/web/20160304053447/http://oai.dtic.mil/oai/oai?verb=getRecord&metadataPrefix=html&identifier=ADA434905, archive-date=2016-03-04, url-status=dead Magnante P.C. (1979) Respirator cartridge end-of-service life indicator, American Optical Corporation

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/ref> Linders M.J.G., Bal E.A., Baak P.J., Hoefs J.H.M. and van Bokhoven J.J.G.M. (2001
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Wallace R.A. (1975) Thermally activated warning system, Patent No

/ref> Roberts C.C. (1976) Colorimetric vinyl chloride indicator, Catalyst Research Corporation

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/ref> Safety equipment Respirators