Substantiation of proposals on the use of insulating apparatus in the liquidation of emergencies with the release of hazardous chemicals

In work, the technical possibilities of using personal respiratory protective equipment are considered as an object of research. Such funds are used in fire and rescue units, during emergency rescue operations related to the liquidation of emergency situations with the release of hazardous chemicals. It is shown that one of the most problematic places for the participation of personnel of fire-rescue units is the contradiction between the protective properties of personal protective equipment and the danger that may be in the organization of the release of a hazardous substance. This applies to the personnel of firefighting and rescue units, which are the first to start carrying out appropriate rescue operations. As a result, even with the full implementation of existing regulatory requirements, work in isolating devices can be dangerous for the rescuer. At the heart of the chosen approach to the solution of the task in view lay the assessment of the possibility to provide such a general protection factor of the insulating device in the assembly with the front part, which will exceed the coefficient of toxic environmental hazard. The study used an analytical definition of the requirements for the testing of compressed air equipment equipped with helmet-masks. It showed that rescuers can work at the epicenter of an accident with the release of hazardous chemicals, if in checking the tightness with the help of devices when creating a test vacuum of 2000 Pa, the rate of the decrease in vacuum will not exceed 32 Pa/min. However, experimental verification of the obtained theoretical results allows to state that the fire and rescue unit will not be able to achieve this requirement. Increasing the test dilution to a level that exceeds 1000 Pa is accompanied by a significant increase in the suction in the system «insulating apparatus – respiratory organs». It has been proven by experience that protection devices are provided with compressed air, equipped with pulmonary automatic devices, which create an overpressure air in the UMS. In this case, the threaded connection of the insulating device with the front part must not be used. This allows to recommend the use of compressed air devices equipped with pulmonary automatic devices as a basic set of isolating apparatuses, creating air overpressure in the UMS Exceptions are subdivisions, in the area of operational departure of which there are facilities on which there is a large number of hazardous chemicals with a toxic hazard coefficient of more than 2,3·10 5 . In this case, they should be completed with complexes of personal protective equipment of ampoule type.


Introduction
Means of personal protection of the respiratory organs, which are in service with the fire and rescue units of the State Emergency Service of Ukraine (hereinafter -SES of Ukraine), were once created in such a way as to ensure the safety of personnel in the worst conditions of a fire. This led to a requirement for a total protection factor, which should be more than 5000 [1]. To date, in accor dance with the Code of Civil Protection of Ukraine [2], rescuers take part not only in extinguishing fires, but also in conducting emergency rescue operations. Including in carrying out rescue operations related to the liquidation of emergency situations with the release of hazardous chemicals.
Therefore, it is urgent to investigate the technical pos sibilities of using personal respiratory protective equipment when performing emergency rescue operations related to the liquidation of emergencies with the release of hazar dous chemicals.

The object of research and its technological audit
As the object of research, technical capabilities of using personal respiratory protective equipment during emergency rescue operations related to the elimination of emergen cies with the release of hazardous chemicals were selected.
Even with the full implementation of existing regu latory requirements, work in isolators can be dangerous ISSN 2226-3780 for the rescuer. Therefore, a technological audit of such object and the results of relevant studies based on it will help to eliminate the contradiction between the protective properties of personal protective equipment and the danger that may be in the hotbed of an emergency situation.

The aim and objectives of research
The aim of research is determination of the requirements that must be met when choosing a kit for personal respira tory protective equipment for the situation of emergency response in the epicenter of an emergency situation with the release of hazardous chemicals.
To achieve this aim, it is necessary to perform the following tasks: 1. Analytical determination of tactical and technical characteristics of insulating devices in assembly with the front part.
2. Assessment of requirements for verification of the equipment of personal respiratory protective equipment.
3. Experimental verification of the possibility of achie ving the necessary indicators.
4. Rationale for recommendations on the selection of a complete set of personal protective equipment in the fire and rescue unit.

Research of existing solutions of the problem
The problem of the participation of rescuers in the liquidation of emergencies with the release of hazardous chemicals is promising. The problem of the participation of rescuers in the liquidation of emergencies with the release of hazardous chemicals is being investigated in the leading countries of the world. So, in the USA in the standard NFPA 15002002 [3,4] it is emphasized that the Federal Emergency Management Agency is responsible for preparing firefighting units for localization and elimination of all emergency situations. Based on this, in accordance with the general requirements of OSHA [5], the organization and staffing structure of the fire brigade is determined not only by the requirements of 29 CFR 1910.156 [6], but also by the requirements of the OSHA 1910.134 re spiratory protection standard [7].
Standards NFPA 1001 [8] and WAC 29630505109 [9] justify the minimum requirements for work in personal protective equipment, specific to the possible conditions for carrying out rescue operations. These conditions are summarized in the standard NFPA 1991 [10], where the personal protective equipment of rescuers is divided into four levels. In this case, Alevel insulating suits provide protection against direct exposure to a hazardous substance. A characteristic feature of suits of this type is that the insulating apparatus is located in a subsuit space, where an overpressure is created. For Blevel suits, the last effect is not the place, even if the insulating device is inside the suit. In this case, rescuers in the units should not only be able to work in protective equipment, but also taking into account the restrictions on their use, carry out appropriate maintenance [11]. In addition, in [12] noted the need to check the insulating apparatus for the possi bility of using it the floor of the insulating suit (level B) when operating under the conditions of the use of chemi cal warfare agents. However, specific indicators and ap propriate methods of checking the insulating apparatus are not listed.
A similar situation exists in Europe, where protec tive clothing is divided into six types. The analysis of the standards of PrEN 943 [13] and PrEN 1511 [14] shows that they are strongly correlated with the levels used in the USA. However, specific quantitative indicators are also not given. For example, in Great Britain, the structure of fire and rescue services is determined taking into account the fire danger of a particular area [15] and all possible threats, including those related to chemi cal hazards [16].
At the same time, in recent studies of issues related to ensuring the integrity of insulating devices, it is assumed that they must ensure safety under the worst conditions that can be during a fire. Proceeding from this, a change in the security of the gas defenders is considered depending on the type of the front part of the insulating apparatus [17], or how shortterm sucking increase inside the insulating apparatus, depending on the severity of the work [18]. Sometimes considered somewhat varies the security of gas defenders depending on the characteristics of the person (in [19] it is noted that the pits inside the apparatus vary with the presence of a mustache or beard). The basis is a check for tightness in gas chambers with a comparison of verification methods [20]. At the same time, the toxic hazard coefficient is assumed to be virtually the same (quantitatively corresponding to the worst fire condi tions), in accordance with which the concentration of the control substance varies. In addition, studies are under way to increase the resistance of protective materials to the hazard, including the reduction of the toxic effects of ionizing radiation [21]. Also, studies are underway to change the minimum leakage from under the face piece through hermetic seals during operation [22].
In Ukraine, the procedure for selecting the means of protection for emergency rescue operations in the ma nagement of emergencies with the release of hazardous chemicals is regulated in [23]. However, even for the ope ration in the complex of personal protective equipment of the first type, it does not specify the features of the choice of the insulating device depending on its placement (inside or outside the suit). At the same time, in [24] it was shown that using a certified insulating suit and any insulating device inside the protective clothing provides a level of protection that allows working in the epicenter of an emergency situation with the release of chlorine (K TH )(Cl 2 )=3.6 . 10 6 .
The peculiarities of work in isolating apparatuses rela tive to an accident at the neutralization station of rocket fuel components, when the toxic hazard factor (K TH ) at the epicenter of an emergency can be reached 3 85 10 5 . ⋅ , were considered in [25]. It was shown that in this case it is advisable to use compressed air apparatus (CAA), however, it was not possible to examine the inside of the front part. As was not considered in [26], where the technique of choosing the front part was proposed and it was shown that when the requirements [27] were satisfied, the coefficient of protection of the regenerative respira tory apparatus K RRA p ( )= ⋅ 2 95 10 4 . , and the compressed air apparatus K CAA p ( )= ⋅ 4 93 10 5 . . Thus, in order to substantiate proposals for the use of insulating apparatuses in the liquidation of emergency situations with the release of hazardous chemicals, it is ISSN 2226-3780 necessary to assess the necessary tightness of the insula ting device assembled with the front part.

Methods of research
5.1. Analytical determination of tactical and technical characteristics of insulating apparatuses in assembly with front parts. At the heart of the solution of the task in view is to provide such a general protection coefficient of the isolating apparatuses (IA) assembly with the front part (FP), which will exceed the coefficient of toxic en vironmental hazards.
At the same time, it is necessary to take into account that in the case of rescue operations for the liquidation of an emergency situation (ES) with the release of hazar dous chemicals (HC), one should not use a mouthpiece box with a mouthpiece and nose clip. Since in this case the face and eyes of the rescuer remain open. That is, it is necessary to analyze the FP in the form of a mask (M), a helmet mask (HM), and a mask with excessive pressure in the undermask space (UMS) with the corresponding [28] protection coefficients K M  29], the normative protective properties of the insulating suit (IS), the overall protection coefficient of the IA in assembly with the FP in the case of equipping the CAA with a helmet mask: It is evident that when working in the RAA, first of all, it is necessary to focus on its protective proper ties. Analogous calculations for CAA (Table 1) indicate that when using CAA assembled from the HM on the IS exact ly the properties of protective clothing determine the level of protective effectiveness of the complex of personal protective equipment. Analysis of the results of Table 1 shows that even du ring rescue operations in the case of emergencies associated with propellant components ( . ),

5.2.
Evaluation of the requirements for tightness testing using instruments in the fire and rescue unit. In addition, it is seen that in the case of equipping the CAA with a helmet mask, the indicator of the overall protection coefficient ( . ) K p = ⋅ 3 27 10 5 is close enough to that con sidered. So, in the case of helmet masks, it is necessary to increase the requirements for the indicators that are monitored during the second test (tightness testing using instruments [30]), since in this case the protection factor of the IS should be not less than: Since the IA protection factor can be considered [29] as: where w l l ≈ − 40 5 /min the air flow rate when operating in compressed air [28]; w s1 -sucking inside the system «apparatus -breathing organs», l/min.
During the second check, it is necessary to ensure that the condition w s l where D D p t / -the rate of discharge drop during the tightness test with the help of instruments, Pa/min; V avolume of air supply system at discharge, l; P i -resis tance of the IS inhalation at the appropriate load, Pa; P p -vacuum in the air supply system during the test, Pa; m -coefficient that takes into account that the air sup ply system is not rigid; P a -atmospheric pressure, Pa.
According to [28], for CAA, the volume of the air supplying system with a discharge does not exceed the dead space of the apparatus, that is V l a ≤ 0 2 , . The ex halation valve should work when a vacuum of no more than 300 Pa is created. Condition (2) when creating, for example, a test vacuum of 2000 Pa is performed if the rate of the drop in the vacuum is: The analysis of expression (5) shows that the experi mental verification of the obtained indices can be carried out with the help of equipment that is used during the second check of insulating devices (checks with the help of special equipment). In this case, the procedure of actions will correspond to those regulated by the operational and technical documentation for the apparatus of the manufac turing plant [30] or SES normative documentation [27].

Experimental verification.
According to [27,30], the apparatus for checking the IS tightness is designed for ISSN 2226-3780 checking insulating devices equipped with HM. Therefore, when testing the CAA, which were equipped with masks or masks with air support in the UMS, a modernized device of Aerotest manufacturer [31] was used (Fig. 1).
The experimental studies were carried out as follows. Vacuum in the UMS is created in the range from 2000 Pa to 750 Pa. In each case, the time (min) and the magnitude of the fall (Pa) of the rarefaction were attempted. Before calculating the parameters characterizing the tightness, it was assumed that at the beginning of work in the II respiratory ventilation w a is approximately 20 l/min, and when working in the CAA, respiratory ventilation is 40 l/min. Three CAAs were selected, which differed in the type of connection (threaded or fitting) CAA with the se lected face and airbreathing resistance (from an elevated 600-650 Pa to a standard one -less than 300 Pa).

Research results
The obtained results of the rate of discharge drop D D p t / are given in Table 2. In accordance with (5), the indices of sucking into the system «CAArespiratory organs» (Table 3) were calculated and, in accordance with (3), the real protection coefficients of the examined CAA ( Table 4). The results of calculations of the overall protection factor of the CAA assembly with the FP are shown in Table 5. In a generalized form, the obtained results are shown in Fig. 2-4.   An analysis of the results shows that in the fire and rescue unit they can't achieve the fulfillment of the condi tion (5). Since the increase in the test pressure to a level that exceeds the value given in the operational documen tation, is accompanied by a significant increase ( Table 2, Fig. 2) sucking inside CAA. In addition, it is established that during emergency rescue operations in the outbreak center with HC emissions, it is impossible to use insula ting devices that require the use of a threaded connection of the TSA with the front part (Fig. 3).
To ensure that rescuers can work under the worst conditions associated with the emission of gaseous HCs, CAA should be equipped with a mask with air support in the UMS, which has nipple connections to the ap paratus (Fig. 4). Taking into account the high sensitivity of the suction, and therefore the tightness of the insulating device to the pressure at which the respiratory automaton operates (Fig. 2, 3), it is advisable to consider the possibility of a hardware reduction of this pressure to 200 Pa. During cleaning and washing the apparatus, it is necessary to pay special attention to the drying of the respiratory automa ton. Continuous monitoring requires no valve adherence to the valve seat.

SWOT analysis of research results
Strengths. The positive effect of the research object on its internal factors is to ensure the safety of the first fire and rescue unit in eliminating emergencies with HC emissions, while reducing the time for performing typical operations. The personnel uses insulating devices that are the floor of protective clothing, rather than very expensive insulating suits of ampoule type, using specialized parts and require additional special training from the rescuers.
Weaknesses. The negative impact of the research object on its internal factors is the impossibility of using compressed air devices equipped with respiratory auto matic devices in the emergency area with a toxic hazard ratio of more than 2.3 . 10 5 . Such devices provide air support in the UMS, during the operation of rescuers.
Accordingly, this requires the person nel to thoroughly study the areas of their exit and the ability to monitor the actual state of the hazard with the help of exis ting control devices. In addition, it is not possible to use regenerative breathing ap paratus and compressed air devices that have a threaded connection of the front part to the apparatus, and also require specification of the regulatory requirements for the procedure for servicing personal respiratory protective equipment.
Opportunities. Opportunities for further research are a comparative assessment of the time to eliminate emergencies with the release of hazardous substances that are stored at highrisk sites in the Donetsk and Luhansk regions. Also in the complexes of personal protective equipment level A and level B, when in the latter over the protective suit there are compressed air devices equipped with masks with respira tory automatic devices that provide air support in the UMS, or helmetmasks.
Threats. Until recently, the problem was determined only for Ukraine and was not considered in detail. In the leading countries of the world, specialized units operate in the hotbed of emergencies with emissions of highly toxic hazardous sub stances.

Conclusions
1. The results of the analytical determination of the characteristics of insulating devices assembled with the front parts showed that the use of regenerative respiratory apparatus in carrying out emergency rescue operations in a hotbed of an emergency with HS emissions is pos sible only within an insulating suit. In the case where the insulating device is located on top of the protective     5 In the latter case, it makes it possible to conduct emergency rescue operations in the hearth of one of the most dangerous for Ukraine emer gency situation associated with the emission of propellant components ( . ).
( % ) K TH NO 100 5 2 3 85 10 = ⋅ 2. The evaluation of the requirements for checking the tightness of compressed air equipment equipped with hel metmasks showed that they can be used in the liquidation of emergencies with emissions of propellant components. In this case, when checking the tightness of the insula ting device assembly with the front part using instruments (second check of the insulating apparatus), the rate of the vacuum drop should not be more than 30 Pa/min when creating a control vacuum of 2000 Pa.
3. The experimental verification showed that in the fire and rescue unit they can't achieve an analytically definite condition, in which the apparatus compress the air equipped with a helmet mask, it is possible to work in an emergency situation with emissions of propellant components. In addition, it is determined that when elimi nating emergencies with the release of hazardous chemicals, it is not possible to use insulating devices that involve the use of a threaded connection between the device and the front. 4. As a basic configuration of isolating devices in fire and rescue units, which can be used for the first locali zation of emergency situations with the emission of gaseous HCs, it is advisable to use apparatus in compressed air. Apparatus should be equipped with pulmonary automatic devices, providing air support in the UMS.
Exceptions are subdivisions, in the area of operational departure of which there are facilities containing a large number of hazardous chemicals with a toxic hazard ra tio of more than 2.3 . 10 5 . In this case, they must be equipped with complexes of personal protective equipment ampoule type.