Filter type RPE,general military filtering gas masks are designed to protect the respiratory organs, face and eyes from PSs, RSs, biological aerosols (hereinafter — BA). The principle of action of gas masks is based on the protection of the respiratory organs from the environment by purifying the inspired air from toxic aerosols and vapours in the filter-absorbing system (hereinafter — FAS). Filtering gas masks do not isolate the airways of the person from the atmosphere and do not enrich the air with inspired oxygen, so they can be used in an environment with an oxygen content of at least 17 % (by volume).

It is also important that the protective features of modern RPE are closely related to the possible effects WMD affecting factors and consequences of industrial accidents. For example, radioactive dust (hereinafter — RD), which falls out after a nuclear explosion, pollutes the surface air layer and gradually settles on the ground. In addition, it can re-enter the above-ground layer together with dust under the influence of wind during the movement of people, vehicles. In this case, RSs will penetrate respiratory organs of military personnel unless they use the RPE.

Upon combat use of highly toxic PSs or HCSs as the result of accidents, they may be in the form of droplets, dispersed aerosol, or gaseous state. In an atmosphere contaminated with PSs or HCSs as gas or aerosol, several lethal doses can be obtained in one breath.

The possibility of using BAs as a weapon, which includes microorganisms of especially dangerous infections, is not excluded. When the size of the aerosol particles is of 1–5 µm, they easily penetrate the lung tissue. The limit dose for humans, e.g. of Q-fever is no more than 10 microorganisms, for tularaemia — 10–50 microorganisms, that is, nanograms of aerosol.

Therefore, modern gas masks must reliably protect the respiratory organs from all of the above factors and meet the criteria for the protective properties of the gas mask.

The protective capability of the gas mask is characterized by dynamic activity (sorption capacity), time of protective action, penetration coefficient, coefficient of inward leakage.

The time of protective action is the time from the start of the passage of an air-vapour mixture containing PS through FAS until the appearance of the maximum permissible vapour concentration of this substance, which is determined by a special indicator.

The penetration coefficient is the ratio of the concentration of aerosols that have passed through FAS and penetrated inside of the gas mask to the concentration of aerosol in the atmosphere. An important factor is the tightness of the front part of the gas mask — gas helmet, connecting points (connecting tube) of other components (coefficient of inward leakage).

The resistance of RPE to various substances and methods of special processing, which increases their reusability; the ability to quickly convert PPE into combat position, ease of use and ease of transportation, other capabilities that improve their use.

Self-contained breathing apparatus (self-contained gas masks) are intended for protection of respiratory organs, face and eyes in the presence of PSs, HCSs in the environment, which are not retained by filtering gas masks, in the complete absence or lack of oxygen in the air, and also during functioning in the foci of chemical contamination under conditions of high concentrations of vapour and density of contamination by any PSs and HCSs. In addition, self-contained breathing apparatus can be used at elevated carbon monoxide contents (concentrations over 1%), forcing water barriers, or performing underwater operations at shallow depths.

The protective properties of the self-contained breathing apparatuses are independent of the nature of RCB contamination or of the concentration of PS and HCS in the air; they are capable of protecting the respiratory organs from any harmful impurities. They are used for rescue, treatment and evacuation activities in the foci of chemical contamination, for work with highly toxic and corrosive gaseous substances, vapours and aerosols of PSs and HCSs, and activities in conditions of lack of oxygen.

It should be kept in mind that in conditions of PS contamination of the atmosphere, timely use of gas masks is important for the protection of the injured and sick persons. The method of protection depends on the nature and severity of the injury or illness, and the victim’s ability to use RPE during medical evacuation.

During the stages and paths of medical evacuation, all injured and sick in need of protection can be divided into 4 groups: those who able to put on and use RPE on their own; able to use RPE, but need assistance when putting it on; injured in the head needing a gas mask with a helmet for the injured in the head; those who need to be placed in collective protection facilities, including anti-chemical facilities, since putting on RPE to victims of this category is contraindicated.

The majority of RPE that are in the operational service with the Armed Forces of Ukraine, stocked up in the Soviet times, have passed shelf lives, and this raises doubts about their reliability. However, in recent years a number of new gas masks have been adopted by the Armed Forces of Ukraine.

For example, in 2018 the AF of Ukraine have adopted general military gas mask ZVP-01U (national nomenclature number — 4240-61-013-2743, the nomenclature number of the Ukrainian Ministry of Defence Classification of Armaments, Military Equipment and Property — Д1111090Y, and it was registered in NATO registry under item number NSN No. 4240-16-0008232) and special military gas mask SVP-01U. The above gas masks successfully passed the tests as per the standards of NATO DSTU EN 136:2003, EN 148-1 (STANAG 4155), EN 14387:2006. And also gas masks comply with the standard of the Ministry of Emergency Situations of Ukraine SOUMNS 75.2-00013528-002:2010.

General military gas mask ZVP-01U is designed to protect eyes, face and respiratory organs of military personnel from chemical warfare agents, BAs, RD and industrial HCSs, gases, vapours and solid or liquid aerosols (time of protective action against chemical warfare agents is 48 hours) [10].

Set of ZVP-01U: mask ОМ-90, absorbing filter OF-07 (possible set NBC-3/SL M), plastic canteen (polyethylene, 0.8 L), haversack, mean weight of the set is 500 g. A set ZVP-01U-F differs only with additional filter Р3 R. The temperature range of application of the gas mask is from –30 °C to + 70 °C, the warranty shelf life is 20 years.

The mask is equipped with a device for drinking, which allows drinking safely from a special plastic canteen (PE, 0.8 L) in contaminated areas, fluid consumption — 230 mL/min. The drinking system is also compatible with CamelBak hydration systems.

The front part of the OM-90 mask is compatible with helmets and breathing apparatus. The mask is available in three sizes, the material of the front part does not cause irritation and provides a high level of protection (the front part is bromobutyl rubber, the interior part is made of natural rubber, the headpiece is rubberised fabric, the plastic components are polyoxymethylene, polyamide). The sweat is removed through the expiration valve. The interior part of the mask reduces the carbon dioxide content of the gas mask and regulates the flow of inspired air, thus protecting the lens from fogging.

FAS can be fitted on both the left and right side of the front part, which makes it possible to right- and left-handed servicemen to conveniently aim the weapon. Inspiration valves for connection to FAS are equipped with Rd 40x1/7” (40x4 mm) threads, which makes them compatible with relevant NATO standards as per EN 148-1. Inspiration resistance at 30 L/min — max 20 Pa, at 95 L/min — max 50 Pa; expiration resistance at 30 L/min — max 60 Pa.

Eyeglass lenses are straight, ensuring compatibility with optical devices while providing sufficient field of view: effective field of view — 73 %, binocular field of view — 34 %. Lens glass is silicate, tempered, which provides resistance to shocks and scratches.

High-quality speech diaphragm (material — polyethylene terephthalate), makes it easy to communicate with or without communication devices, minimum speech intelligibility — 95 %.

OF-07 absorbing filter is specially designed to protect against WMD or leakage of highly hazardous chemicals. It provides protection of the respiratory tract from solids, aerosols, irritating sprays, smoke-generating substances, highly toxic particles, PSs BAs (fungi, bacteria, viruses), chemical warfare agents of asphyxiation, vesicant, neuroparalytic, general poisonous and physicochochemical action according to the type of A2B2E1SXP3DR (Table 2). Diameter — 115 mm, height — 78 mm, weight — 320 g ± 5 %, shelf life — 20 years.

Table 2

Characteristics of absorbing filter OF-07 (А2В2Е1SXP3DR)

P3 R filter is part of ZVP-01U-F gas mask kit, and it provides reliable airway protection against radioactive iodine and its organic components (iodomethane 129, 131), radioactive particles, etc. P3 R filter has the following characteristics: diameter — 110 mm, height — 85 mm, weight — 330 g, shelf life — 10 years [15].

New ZVP-01U gas masks are approved for use in the Armed Forces of Ukraine. In view of recent events in the world and the urgent need of the Armed Forces of Ukraine for modern gas masks, the Ministry of Defence of Ukraine has planned and successfully conducted field and laboratory tests of the general military gas mask ZVP-01U. As a result of the tests, the Minister of Defence by his order allowed the general military gas mask ZVP-01U to be used in the troops, and the gas mask itself fully complies with the requirements of the standards EN 136 (Class III) NATO Triptych (Fig. 1).

Special military gas mask SVP-01U is designed for special forces (completion of special tasks requiring an increased field of view) and provides protection of eyes, face and respiratory organs of military personnel against chemical warfare agents, BAs, RD and industrial HCSs, gases, vapours, solids and liquid aerosols [10].

A set of SVP-01U: mask SМ-6S, absorbing filter NBC-3/SL (may be available with OF-07), haversack, the weight of the set is 560 g. SVP-01U-M set differs with SM-6SM modified mask with a drinking device and a plastic canteen (polyethylene, 0.8 L).

The front of the SM-6S (SM-6SM) mask has a large curved panoramic protective glass that provides a wide field of view, does not fog and allows the use of spectacles, however, the use of optical devices is complicated. It is available in a single universal size, due to the elastic material of the front part and the tightening straps, it fits tight to any size and type of adult face.

Materials of SM-6S (SM-6SM) mask and other properties are identical to OM-90 mask in gas mask ZVP-01U. Absorbing filter NBC-3/SL provides reliable protection of respiratory tract against BAs and PSs according to their type: А2В2Е2К2HgSXP3DR (Table 3). Diameter — 110 mm, height — 85 mm, weight — 320 g ± 5 %, shelf life — 20 years.

Table 3

Characteristics of absorbing filter NBC-3/SL (А2В2Е2К2HgSXP3DR)

Filtering gas mask FP-М95U (FP-М05U) is designed to protect respiratory organs, eyes and facial skin of the military personnel against exposure to chemical warfare agents, RD, BAs and industrial HCSs due to purification (filtration) of contaminated air in FAS (time of protective action against chemical warfare agents is more than 24 hours) [11].

Gas masks FP-М95U, FP-М05U were adopted in AF of Ukraine in 2013 and they comply with standards of NATO EN 136, EN 148-1 (STANAG 4155), FAS complies with EN 14387. A set of FP-М95U (FP-М05U): mask M-95U (M-05U), absorbing filter CF-22 (CF-32), plastic canteen (polyethylene, 1 L), haversack. FP-М05U gas mask differs from FP-М95U with better design of inspiration and expiration valves. The temperature range of application of the gas mask is from –50 °C to + 70 °C, the warranty shelf life is 10 years.

Mask of the gas mask М-95U (М-05U) is available in two sizes (M/L — standard, L — small) polyester head harness is covered with elastane, the material of the front (external side of the mask — halobutyl elastomer, inward side of the mask — silicone) provided antiallergic contact with facial skin. FAS can be attached to both the left and right side of the front. The valve plate is made of silicone, for connection with FAS, the inspiration valves are equipped with Rd 40x1/7” (40x4 mm) thread. Inspiration resistance at 30 L/min — max 45 Pa, at 95 L/min — max 100 Pa.

Eyeglass lenses are high quality (polyamide lenses), they are curved, providing a sufficient field of view (effective field of view — 80 %), however, the use of optical devices is complicated. Separate lenses allow for the folding of the mask in half for compact packaging in a bag.

The speech diaphragm provides audibility at a distance of 2 m, which makes it easy to communicate with or without communication devices. The gas mask is equipped with a drinking device that allows drinking safely from a special plastic canteen (1 L) in contaminated areas, fluid intake — 250 mL/min.

Absorbing filters CF-22, CF-32 provide protection of the respiratory tract from solids, aerosols, irritating sprays, RSs, BAs according SF-22 to type of A2B2E1P3, and SF-32 to type of A2B2E2K2P3 (Table 4). External material of filters — reinforced polyamide, weight of CF-22 — 260 g, weight of СF-32 — 366 g.

Table 4

Characteristics of absorbing filters СF-22 (A2B2E1P3), СF-32 (A2B2E2К2P3)

Also, gas mask FP-М95U (FP-М05U) is available with versatile FAS: CFR-22CBRN (A2B2E1K1 P3 RD) for protection against chemical, biological and RSs, gases (cyan [CN], tear gas carbon sulphide [CS], organic, inorganic and acid gases and vapours, toxic and RD, aerosols, bacteria, viruses); CF-22CBRN (A1B1E1K1 NO CO20 P3 RD) with additional protection against NO, CO; CFR-32CBRN (A2B2E2K1 Hg NO CO20 P3 RD) with additional protection against NO, CO, Hg. [12].

Filtering gas mask MP-5U is designed to protect eyes, face and respiratory organs of military personnel against chemical warfare agents, BAs, RD due to purification (filtration) of contaminated air in FAS of the gas mask [17]. The MP-5U gas mask was adopted by the AF of Ukraine in 2006 and meets NATO standards EN 136, EN 148-1 (STANAG 4155).

A set of MP-5U: mask MP-5U, absorbing filter FP-5, plastic canteen (0.6 L), connection hoses with ball valve, haversack. The front of the mask MP-5U has a curved panoramic protective glass, which provides a wide field of view, but the use of optical devices is complicated; it is available in four sizes, the material of the front part does not cause irritation and provides a high level of protection. The filter is attached to the front of the mask in the centre. Inspiration valves for connection to the filter are fitted with Rd 40x1/7” (40x4 mm) thread in accordance with EN 148-1. The time of the protective action of the material of the mask against drip PSs is at least 24 hours. The coefficient of penetration of the test aerosol under the mask (inward leakage coefficient) through the lines of obturation and through other nodes is not more than 0.05 %. The volume fraction of carbon dioxide in the inspired air is not more than 1 %. The effective area of view of the mask relative to the normal area is 70 %. Resistance to special processing means — 60 % solution of ethyl alcohol. The time of the protective action of FP-5 against gaseous substances at a constant airflow of 30 dm³/min by chlorine cyanide is at least 33 minutes, and by chlorpicrin — not less than 37 minutes.

Coefficient of penetration of paraffin oil vapour at a constant airflow of 30 dm³/min is not more than 1 × 10^-4%. The resistance of the FP-5 filter to constant airflow at a flow rate of 30 dm³ /min is not more than 130 Pa, at 160 dm³/min — not more than 1,300 Pa. Respiratory resistance at a volumetric flow rate of 95 dm³/min during inspiration is not more than 250 Pa, during expiration — not more than 300 Pa.

Passability (specific flow rate) of the drinking system is not less than 200 mL/min. Weight of the mask of the gas mask is not more than 550 g, the weight of the filter is not more than 270 g, the weight of drinking device in assembly (without fluid) is not more than 250 g, the weight of gas mask in a set is not more than 1,200 g. Shelf life in non-heated rooms at a temperature of –40 °C to +50 °C and relative humidity up to 98 % in the packaging of the manufacturer is 10 years [12].

Self-contained individual breathing apparatus IAD-1U is a special PPE of the respiratory system, eyes from any hazardous impurities in the air, regardless of their properties and concentrations, and is used in cases where the filtering gas masks do not provide appropriate protection, as well as in the absence or insufficient oxygen content.

The apparatus is used for emergency rescue teams of armoured combat vehicles. It allows team members to leave a sunken combat vehicle and breathe safely in the water until rising to the surface, as well as to hold on the surface. It was adopted by AF of Ukraine in 2019.

A set of IAD-1U: regenerative absorber RT-1, swimming vest with the breathing bag ATE-1, emergency oxygen vessel RAT-1, mask, breathing hose with a mouthpiece, a bag for carrying a set, a silk cloth for the care of glasses F40 MASKPOL S.A. The warranty shelf life of the device in the packaging of the manufacturer in closed non-heating storage at temperature fluctuations from –30 ˚С to +40 ˚С and relative humidity of 15 to 65 % is 5 years. IAD-1U completely isolates the respiratory system from the surrounding atmosphere, provides breathing due to the artificial respiratory mixture, which is formed due to chemical reactions occurring in the regenerative absorber. The main tactical and technical parameters of IAD-1U are given in Table 5.

The regenerative absorber RT-1 is designed to produce oxygen by absorbing carbon dioxide and the moisture contained in the exhaled mixture. RT-1 consists of a housing filled with oxygen-containing substance, the upper and lower covers, the starting device, which is located directly in the absorber housing; two necks — one for connecting with the breathing bag, the other for attachment to the respiratory hose with the mouthpiece — both are located on the top cover of the regenerative absorber. A regenerative absorber is a removable unit of apparatus for single use, providing sufficient oxygen supply to the user’s respiratory system for at least 60 minutes, at a pulsating flow of the respiratory mixture in the amount of 35 dm ³/min and the absorption of carbon dioxide released by breathing.

Table 5

The main tactical and technical parameters of IAD-1U

Swimming vest with breathing bag АТЕ-1 consists of covering and breathing bag. Carrying elements and pockets for the absorber and the emergency vessel are attached to the covering. The breathing bag is equipped with connecting ends and a drain valve. The breathing bag must withstand a pressure of 17.5 kPa and be leak-tight at 1,000 Pa.

Emergency oxygen vessel RAT-1, a removable unit of the apparatus intended for single use, consists of one or two small cylinders equipped with valves, the design of which prevents accidental opening. The design of connecting the emergency vessel to the breathing bag makes it easy to replace empty cylinders with full ones. The breathing hose with mouthpiece is designed to isolate the respiratory organs from the environment, the direction of the exhaled gas mixture into the regenerative absorber RT-1, as well as supplying gas mixture resulting from a chemical reaction to the respiratory organs, providing mouth breathing on the contaminated surface and under water.

The mask is designed to protect the eyes from hazardous substances and to provide vision under water, it is firmly pressed to the face, soft and does not cause any significant pressure, the attachment of the mask on the head provides the possibility of adjustment.

The design of the bag allows placing the apparatus in it and carry it over the shoulder and in the hand, and also eliminates the possibility of direct ingress of drops of moisture and coarse dust.

The principle of work of IAD-1U is as follows: the oxygen-containing substance of the regenerative absorber RT-1 reacts with exhaled carbon dioxide and water with oxygen formation.

The rate of chemical reaction in the regenerative absorber at normal ambient temperature is relatively small and cannot provide normal breathing, respectively, to quickly start these reactions at the required speed and to provide respiration in the first minutes, a starting device is used. It consists of a starting briquette and oxygen-containing substance, an ampoule with sulphuric acid and a device for crushing it.

When the ampoule with acid is crushed, approximately 12 L of oxygen is released and the upper part of the regenerative absorber is heated, providing the required rate of chemical reactions. Further release of the required amount of heat occurs during exothermic reactions that take place with the participation of the oxygen-containing substance of the regenerative cartridge [12].

Discussion. The results of study of the technical characteristics of the latest developments of RPE have confirmed the great interest in this issue in Ukraine and countries of Eastern Europe [13–15].

The relevance of improving RPE is due to the high level of chemical and radiation threats in the region and the nature of the emergencies of man-made origin [16, 17].

Therefore, based on the study of the latest samples of RPE, which were adopted by the AF of Ukraine, we have found that: gas masks ZVP-01U and SVP-01U have a shelf life of 20 years — quite high in comparison with analogues, this makes it possible to lay them on long-term storage and accumulate their stocks, gas masks MP-5U and FP-M95U (FP-M05U) have a shelf life of 10 years.

Binocular masks of gas mask ZVP-01U with straight glass, which is resistant to mechanical influences, allow the use of gas mask with optical devices.

The quality of materials of masks of gas masks ZVP-01U, SVP-01U and FP-M95U (FP-M05U) provides carrying out of special processing by regular means and solutions without deterioration of gas mask condition.

Panoramic glass is contained in the masks SVP-01U and MP-5U, but the maximum panorama is in SVP-01U, which ensures its use by special forces requiring high visibility, medical staff, specialists in rescue and evacuation services and forces, civil protection forces and civil population.

FAS connecting elements of gas masks ZVP-01U, SVP-01U, MP-5U and FP-M95U (FP-M05U) comply with NATO standard EN 148-1, making the gas masks compatible with other filtering boxes designed to protect against different HCSs of an industrial nature, depending on the conditions (supplied separately).

The versatility of the size of gas mask SVP-01U increases the possibility of its use for any size and type of face of an adult, and the wide panoramic glass allows taking care of the injured persons if there are no contraindications to the use of the gas mask; it allows the use of spectacles.

The shape of the mask and the separate lenses of the gas mask FP-M95U (FP-M05U) provide folding of the mask in half for compact packaging in a bag. Such an possibility will be appropriate for special forces; virtually all the gas masks under consideration have the ability to provide FAS attachment on both the left and right sides of the front, which makes it possible to right- and left-handed servicemen to conveniently aim the weapon, except for the gas mask MP-5U, where the filter is attached in the front part of the mask in the centre.

The breathing apparatus IAD-1U is the unique among the samples of self-contained RPE, except for the Soviet ones, it is an analogue of the self-contained gas mask IP-5 and, unlike IAD-1U, it has a mouthpiece, which makes it possible to temporarily stop the supply of the exhaled gas mixture to regeneration after actuation of the apparatus, further continuing its use, which is impossible in the helmet mask IP-5; this feature can be important during the evacuation of two people with one breathing apparatus.

Conclusion

1. Ukraine is in a situation that requires a highly effective system of protection against RCB contamination in the AF of Ukraine, including RPE. The technical compliance of modern RPE must efficiently withstand the possible threats in the application WMD and upon the activities in the areas of RCB contamination as a result of terrorist acts or accidents (destruction) of nuclear power plants and enterprises of the chemical industry, the ability to stock up RPE and their long-term in-use storage.

2. The majority of RPE that are in the operational service with the Armed Forces of Ukraine, stocked up in the Soviet times, have passed shelf lives, and this raises doubts about their reliability in terms of protection. Produced according to Soviet standards, they do not meet NATO standards (especially compatibility of FAS use), therefore, their stock up is impractical and needs immediate replacement.

3. Today, the best samples of domestic production meet the following criteria: reliable work of gas masks in different conditions; increasing the field of view and possibility to use with optical devices; technological compatibility of breathing valves and intercoms to NATO standards; enhancing the protective properties of FAS with respect to protection against a wide range of HCSs and their high shelf lives EN148-1; resistance of RPE materials to special processing means, which increases their reusability; the ability to quickly convert PPE into combat position; ease of use and convenient transportation; other features that improve their use.

4. An important direction in the development of weaponry and military equipment in Ukraine is the improvement of domestic technologies and development of own production of personal protective equipment, technologically compatible with the samples that are in the operational service with NATO countries.

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