Fire extinguishing efficiency of perfluoro-isohexenes

Показана нехватка современных веществ для газового пожаротушения, вызванная борьбой с глобальным потеплением. Описаны подходы к поиску перспективных газовых огнетушащих веществ (ГОТВ), применявшиеся ранее. Предложен новый подход и найдены с его помощью принципиально новые огнетушащие вещества, полностью удовлетворяющие современным экологическим и токсикологическим требованиям. The paper is devoted to investigation of perfluoro-isohexenes as new gaseous fire suppressants. The current situation in the field of fire protection with chemically active gases is analyzed. The problem of greenhouse gases replacement during fire suppression is discussed. The disadvantage of existing alternative agents is short atmospheric lifetime. It is also shown that the existing approach to development of new gaseous fire extinguishing substances is almost exhausted. New group of gaseous agents for fire suppression - perfluoro-isohexenes - is proposed based on new approach. These substances are non-toxic and have very short atmospheric lifetime. Two types of experimental equipment were used in this work to investigate properties of aforesaid substances as extinguishing agents. It was implemented to determine flammability limits of gaseous mixtures and fire extinguishing concentration of gaseous fire suppressants having high boiling point. It was shown that perfluoro-isohexenes are non-flammable and their extinguishing properties are substantially better than properties of the nearest equivalent - perfuoroethyl-isopropylketone. These results are discussed from the point of view of the features of transformation of considered fire extinguishing substances in a flame.

Immunotoxicity of an Electrochemically Fluorinated Aqueous Film-Forming Foam

Aqueous film-forming foams (AFFFs) are complex per- and polyfluoroalkyl substance (PFAS)-containing mixtures used extensively as fire suppressants. AFFF-impacted groundwater and surface water have contaminated drinking water with PFASs in many communities, raising concerns about health effects from drinking water exposures. As individual PFASs have been identified as immune hazards, the immunotoxicity of complex PFAS mixtures is also a concern. Adult female and male C57BL/6 mice were given a commercial AFFF formulation for 10 days via gavage; administered dose was based on combined content of perfluorooctanoate (PFOA) and perfluorooctane sulfonate (PFOS) measured in the formulation (0, 1.88, 3.75, 7.5, or 10 mg PFOS+PFOA/kg body weight). A PFOA positive control of 7.5 mg/kg body weight was also given. Compared with the 0 mg/kg group, the following changes were noted: Body weights of males exposed to 7.5 and 10 mg PFOS+PFOA/kg were reduced by 15%, on average; female body weights did not differ. Average relative liver weights were increased 50%–200% in males and 37.5%–193% in females and liver peroxisome proliferation was increased 2- to 12-fold in all doses of both sexes. Antigen-specific antibody production was suppressed, on average, by 13% in males and by 12.4% in females across all doses. Spleen cellularity and lymphocyte subpopulations did not differ by dose for either sex. Our data indicate that though this complex PFAS mixture contained fairly low PFOA content, it induced changes in C57BL/6 mice similar to changes induced by PFOA alone, likely due to the presence of PFOS and many other PFASs.

The Method of Force of Fire in High-Rise Building by Guide to the Fire Safety Concepts Tree: Focusing on Manually Fire Suppression Strategy

This study analyzes the issue of the supply of force of fire in the high-rise buildings, and proposes an efficient method to do so. The results are as follows. First, in terms of Detect fire, it is necessary to shorten force of fire supply time by diversifying fire alarms such as alarms, vibrations, and voices from outside, clarification of fire occurrence points, and marking of fire. Second, with regard to communication signals, strengthening the installation target of wireless communication auxiliary facilities, supplementing the installation of repeaters, and constructing a multicommunications network were proposed. Third, in terms of Decide action, it is necessary to supply firefighter and firefighting equipment with the method of crossing of a river in adjacent buildings. Fourth, in terms of Respond to site, helicopters and emergency elevators are used to assist in the supply of firefighting equipment using drones. Easy-to-break glass windows and identification marks are required in every floor. Finally, in terms of applying fire suppressants, water can be supplied by means of a helicopter adjacent to the structure.