Winter fires are frequent, we should pay more attention to fire safety issues, many fire extinguishing agents in heptafluoropropane has received widespread attention, as a clean gas fire extinguishing agent instead of halon fire extinguishing agent, is also often used in all kinds of computer rooms, power distribution rooms, substations, archives, containers, industrial equipment and other key protection areas, so in the endHeptafluoropropane extinguishing agentWhat is the principle, many people are not clear, is it harmful to the human body? In order to answer this question, the following Shengshi Public Security will give you a detailed interpretation!
1. Introduction to heptafluoropropane
Heptafluoropropane is 1,1,1-2-3,3,3-heptafluoropropane according to China's chemical system nomenclature, called HFC-227EA according to the international common halide nomenclature, its chemical formula is C3HF7, which is composed of C (carbon), F (fluorine), H (hydrogen) three elements, it is a colorless and odorless, non-conductive, non-polluting protected object of gaseous fire extinguishing agent, heptafluoropropane fire extinguishing principle is a combination of physical and chemical reactions, relying on the absorption of heat energy in the fire, The physical method of reducing the flame temperature should react with the free radicals produced by thermal decomposition and the active free radicals to interrupt the chemical reaction process of the combustion chain reaction to achieve the purpose of extinguishing the fire. In the actual fire extinguishing process, the fire is extinguished through chemical and physical reactions, mainly chemical reactions.
2. The principle and characteristics of heptafluoropropane fire extinguishing
1) Short fire extinguishing time and good fire extinguishing performance.
Heptafluoropropane agent is mainly used to extinguish fires through physical cooling and heat absorption, and heptafluoropropane belongs to the same class as air conditioning refrigerant, so it is an effective heat conversion agent. The physical fire extinguishing effect of heptafluoropropane is to absorb the heat energy in the fire through vaporization after the release of the liquid agent, resulting in a decrease in the flame temperature and a slow free radical chain reaction, so that the combustion reaction cannot be maintained. In addition, heptafluoropropane also has a chemical reaction, in the process of fire extinguishing heptafluoropropane thermal decomposition to produce CF3, CF2, CF3CFO and CFO and other fluorine-containing radicals, these fluorine-containing radicals and H, O, Oh, Ho2, O2-, No and other active free radicals in the combustion reaction process react to produce CO2, H2O, HF, etc., thereby interrupting the chemical chain reaction in the combustion process. The rapid reaction and excellent combustion inhibition of heptafluoropropane can prevent catastrophic fires.
2) Pyrolysis and its impact on the equipment in the protection area.
Heptafluoropropane is relatively stable at room temperature, but at high temperatures (about 500 °C) it begins to decompose hydrogen fluoride (HF), which has a strong pungent odor and can be detected before reaching the maximum hazardous exposure concentration, and has a certain weak acid corrosive effect on personnel and electronic equipment. However, a large number of experiments have confirmed that the shorter the spray time and fire extinguishing time of heptafluoropropane fire extinguishing agent, the lower the concentration of hydrofluoric acid produced, and these concentrations will not have a corrosive effect on electronic and other equipment. In order to shorten the impact of thermal decomposition on the protected area, the GB50370 specification design standard of the "Code for the Design of Gas Fire Extinguishing System" stipulates that the spray time of heptafluoropropane should not be greater than 10 seconds, and it is not recommended that the heptafluoropropane fire extinguishing system be used in the environment of more than 500 high temperature protection areas. In addition, heptafluoropropane does not contain particles or oily residues after release, is completely vaporized in the atmosphere without leaving residues, does not conduct electricity, and does not damage electronic equipment, computers, archive documents, communication equipment or complex medical equipment when extinguishing fires.
3. Is heptafluoropropane harmful to the human body?
The non-toxic (NOAEL) concentration of heptafluoropropane is 9%, and the toxic (Loael) concentration is 105%, in accordance with the provisions of NFPA2001 of the "Code for Fire Extinguishing Design of Clean Gas Fire Extinguishing Agent", personnel do not need to evacuate the protection area when the concentration is lower than 9% of the design concentration; When the design concentration is between 9% and 105% of the time, the person does not stay in the protected area for more than 5 minutes; More than 10At the design concentration of 5%, no personnel are allowed to stay in the protected area, otherwise it will lead to personal safety. According to the "Code for the Design of Gas Fire Extinguishing System" GB50370, the design concentration of heptafluoropropane fire extinguishing system is less than 10%, and such a protective concentration will be safe for the human body.
4. The impact of heptafluoropropane on the environment.
The greenhouse effect is currently used as the basis for influencing global warming in the world, and in order to effectively evaluate the impact of a fire extinguishing agent on environmental warming, its direct and indirect effects on the environment should be considered first. Heptafluoropropane does not contain chlorine or bromine, does not destroy the ozone layer after extinguishing the fire, and has an ozone layer potential ODP of 0, which is a clean fire extinguishing agent. According to the IPCC Fourth Assessment Report, the greenhouse effect index value of heptafluoropropane is 3220, but because heptafluoropropane is only released when a fire occurs, its impact on the greenhouse effect is negligible.
In recent years, perfluorohexanone fire extinguishing agent (trade name NOVEC1230 fireproof liquid) has high fire extinguishing efficiency, no activity on ozone, ozone depletion potential ODP = 0, greenhouse effect index value GMP is only 1, non-conductive and other characteristics, has been put into use in North America, Europe, Australia, Japan, South Korea and other international use, I believe that the future will shine in the field of fire protection.
5. Mature technology.
The heptafluoropropane fire extinguishing system can meet the requirements of the clean gas fire extinguishing system in terms of fire extinguishing performance, safety of protected objects, human safety and environmental impact. At present, NFPA2001 (American design standard for clean chemical fire extinguishing systems), ISO14520 (European design standard for gas fire extinguishing systems) and GB50370 (Chinese gas fire extinguishing system design code) have incorporated heptafluoropropane fire extinguishing systems into their standard systems; Heptafluoropropane fire extinguishing system application since the early 90s of the 20th century, has nearly 20 years of application history, in the design and application, system hardware and agents and other aspects have been increasingly mature, achieved good results, accumulated rich experience, heptafluoropropane fire extinguishing system application has become the most widely used system in the gas fire extinguishing system market.
Heptafluoropropane fire extinguishing system is one of the widely used gas fire extinguishing system products in China, which can be mainly used to protect electronic instruments, precision instruments and valuables, such as computer information rooms, telecommunications and communication facilities, power distribution rooms, substations, important cultural relics and other key protection areas.
To sum up, it is about the principle and extended knowledge of heptafluoropropane fire extinguishing, and the problems encountered by everyone in the use of heptafluoropropane can leave a message to us, and Shengshi Zhi'an will answer it for you in a timely manner!
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