Methodology of assessing the quality of mask filter elements for protection of people, and their vital functions in case of fire

. This abstract delves into an investigation concerning the toxicity of the gaseous environment encountered in the context of fires within public structures, encompassing shopping malls and entertainment centers. These fires engender the release of a host of highly toxic gases, prominently including phosgene, carbon monoxide, and hydrogen cyanide. It is noteworthy, however, that prevailing portable filtering self-rescue masks employed during the evacuation from fire-stricken areas do not offer protection against phosgene. This discrepancy is attributed, in part, to the absence of stipulated requirements for safeguarding against phosgene within the regulatory documentation governing mask specifications. In response to this, a comprehensive methodology has been devised for evaluating the protective attributes of filtering and absorbing components, concomitant with the establishment of a delineated roster of gases to serve as benchmarks for assessing reliability. The culmination of these research has resulted in the development of a novel fibrous material and a respiratory mask design, specially tailored to protect against the toxic gases encountered during fires within public structures. These innovations can improve the protective effectiveness of masks, making them better suited to protect people in such dangerous situations.


Introduction
Fire safety regulations in shopping malls, entertainment centers, and other public buildings are essential for ensuring the safety of the constant influx of visitors from various age groups and social backgrounds, as well as for diverse purposes such as commerce, entertainment, gastronomy, and more [1][2][3].
Fires in such buildings can lead to casualties on a large scale.For example, on March 25th, 2018, a fire occurred in the four-story shopping mall "Winter Cherry" in Kemerovo.The center of ignition was located on the top floor with several cinema halls and children's play areas with amusement machines.As a result of the fire, 60 people died, including 37 children, and 79 people were injured, including 27 children.
The most dangerous fire factors in such buildings are the placement of entertainment and children's areas that have a large flammable load (stuffed toys, cladding materials, decorative plastic coverings, pool fillers with various plastic compounds, and synthetic fillers for trampoline mats, etc.).The above-mentioned combustible materials pose a significant fire hazardin terms of the toxicological impact of gases generated during combustion on evacuating people [4][5][6][7].
According to the fire safety standards, workers and visitors of shopping malls and entertainment centers must be provided with portable self-rescue masks to protect their respiratory organs in case of fire.
The choice of self-rescue masks should be basedon the forecasting the toxicological situation, considering the most dangerous fire factors.New data on the toxicity of flammable materials in public buildings confirm the need to develop additional requirements for selfrescue masks [5].
The purpose of the research is to develop additional requirements for filtering self-rescue masks used in shopping malls and entertainment centres for evacuating people in case of fire, based on an analysis of the toxicological situation.

Materials and methods
In a prior study by Puzach, Bachurin, and Akperov [4], it was underscored that the combustion of soft children's toys gives rise to the release of highly toxic gases, including carbon monoxide, hydrogen cyanide, and phosgene, in concentrations that pose imminent threats to human life and well-being.Importantly, it was elucidated that the genesis of these toxic gases is not intrinsically tied to the ignition of the fire but is instead contingent upon the materials consumed by the fire.Regrettably, this nuance has been considerably underestimated within the purview of fire safety considerations concerning shopping malls, entertainment centers, and children's recreational areas.Consequently, it becomes imperative to account for the multifaceted effects of these aforementioned gases when evaluating the protective efficacy of self-rescue masks.
Exposure to carbon monoxide induces a state of bodily intoxication, manifested by symptoms such as nausea, vomiting, dizziness, blurred vision, and, in severe cases, loss of consciousness [7].Physical exertion exacerbates the poisoning, resulting in the formation of carboxyhemoglobin in the bloodstream, which subsequently impairs the functioning of the nervous and cardiovascular systems and may culminate in fatality.
Upon infiltration into the human body, hydrogen cyanide disrupts intracellular oxygen transport, leading to the paralysis of nerve centers and, in severe instances, fatality [7].Phosgene, recognized as an exceedingly toxic compound [7], presents a unique feature in its effect on humans.It lacks overt irritant effects and manifests a latent period.At low concentrations, phosgene elicits irritation of the mucous membranes of the upper respiratory tract and the eyes, provoking lacrimation, coughing, and nausea.In high concentrations, phosgene can be lethal.
Consequently, even modest concentrations of the CO+HCN+COCl2 amalgamation can impede the orderly evacuation of individuals and result in mass poisoning.Furthermore, grave repercussions for human health may ensue after evacuating fire-stricken zones.The combined impact of carbon monoxide and hydrogen cyanide (CO + HCN) has been observed to exhibit an augmented effect compared to their individual influences.Although the consequences of introducing phosgene to this mixture remain incompletely explored, strong conjecture suggests that it would substantially amplify the overall toxicity of the gaseous environment.
In view of the potential for delays in evacuation, including scenarios with closed emergency exits and obstructions in evacuation routes, there is a compelling need for portable self-rescue masks capable of shielding individuals from exposure to a blend of highly toxic gases.
Activated carbon, widely utilized for the absorption of deleterious combustion byproducts, has been experimentally shown to enhance the protective properties of respiratory masks when combined with soda limea composite of sodium hydroxide (NaOH) and slaked lime (Ca(OH)2).This combination is found to be particularly effective in mitigating the adverse effects of phosgene on human health.Notably, activated carbon serves both as a sorbent for phosgene and as a catalyst, facilitating the reaction between atmospheric moisture and phosgene, thereby breaking down the latter into hydrochloric and carbonic acids.In contrast, soda lime demonstrates proficiency in the absorption of phosgene but lacks catalytic properties.The juxtaposition of these divergent sorption mechanisms underpins the rationale for the optimal combination of these two sorbent agents.Empirical investigations have further reinforced the preference for their concurrent use [7].

Results
The requirements governing the protective attributes of self-rescue masks deployed in multifaceted shopping malls and entertainment centers are stipulated within regulatory frameworks, such as the National Standard of the Russian Federation, GOST R 53261-2019, titled "Firefighting Equipment: Fire Filtering Self-Rescue Masks for Protecting Individuals from Toxic Combustion Products during Fire Evacuation from Smoke-Engulfed Premises -General Technical Requirements and Test Methods".These standards delineate the protective duration offered by self-rescue masks against toxic gases, encompassing carbon monoxide, hydrogen chloride, hydrogen cyanide, and acrolein, while not explicitly addressing phosgene.
Concomitantly, a comprehensive patent inquiry has been instrumental in pinpointing the principal ergonomic shortcomings inherent in established self-rescue mask designs, which predominantly encompass unwieldy weight and inadequate foldability [8][9][10][11].
This manuscript proposes a novel mask design aimed at safeguarding the respiratory system against combustion byproducts, underpinned by an intricate understanding of the idiosyncrasies of toxicological conditions prevalent during conflagrations within shopping malls and entertainment centers.The innovative design endeavors to rectify the most salient drawbacks associated with conventional counterparts.
The devised technical solution for respiratory protection against combustion byproducts can be characterized as a composite apparatus, comprising a facial mask equipped with an internal cavity replete with sorbent material, an integral one-way valve (Zunz valve), and mechanisms for securing the mask to the user's head.
The mask's composition consists of a filtering element, consisting of two layers of cotton fabric intricately interconnected to form a contiguous cavity, which is impregnated with a sorbent material (sodium lime).The external layer is constructed from an impermeable flexible material, establishing an additional compartment when sealed alongside the filter element via the one-way valve (Zunz valve).This innovative configuration enables exhaled air to traverse into the supplementary compartment, allowing it to pass through the absorbent agents integrated within.

Discussion
The design of the device for protecting the respiratory system from combustion products is a face mask covering the respiratory system, including a cavity filled with sorbent, and a check valve.The device also includes connectors for attaching the face mask to the head, which are, for example, belts with the length ties made of elastic material (Fig. 1).The mask consists of two layers of cotton fabric, which allows to reduce the weight of the device by using lighter material.The check valve can be made of rubber (silicone) or a flexible membrane.The use of lighter materials has resulted inreducing the weight of the developed device for respiratory protection.
The device can be manufactured using thread, adhesive and other connection methods, taking into account the composition and structure of the materials used.

Conclusion
The findings of this study are summarized as follows: The primary fire hazard factors within shopping malls, entertainment centers, and public structures have been ascertained.These structures emit highly perilous gases-specifically, carbon monoxide, hydrogen cyanide, and phosgene-when subjected to a fire incident.
An exhaustive evaluation of the prevailing shortcomings in current respiratory protection apparatus utilized in the evacuation of individuals from fire-stricken areas has been conducted.This analysis has culminated in the formulation of a systematic approach for assessing the efficacy of self-rescue devices intended for evacuating individuals from conflagrations within shopping malls, entertainment centers, and analogous public venues.
In conclusion, a respiratory protection mask has been developed to address the specific challenges posed by the toxicological circumstances encountered during fires in shopping malls, entertainment centers, and comparable public edifices.