Is heptafluoropropane harmful to the human body? Gas fire extinguishing manufacturers deeply analyze the characteristics of heptafluoropropane (FM200) for you

First of all, as a type of gas fire extinguishing system, heptafluoropropane has been favored by the majority of users for its high fire extinguishing performance and the characteristics of no secondary pollution. Secondly, with the country's emphasis on fire protection, heptafluoropropane fire extinguishing system has gradually become an essential fire-fighting equipment in key protection places such as computer rooms, power distribution rooms, archives rooms, important databases, containers, etc. However, when the editor received customers, he found that the customers were still very concerned about the issue of "whether heptafluoropropane is harmful to the human body". So today we will talk about this issue in detail.

What is heptafluoropropane? According to GB18614, Heptafluoropropane (HFC227ea) Fire Extinguishing Agent, heptafluoropropane should be named 1,1,1,2,3,3,3-heptafluoropropane according to my country's chemical system nomenclature. It is called HFC227ea according to the international general nomenclature of halogenated hydrocarbons. It is also called HFC-227, FE-227 and FM-200. Its chemical formula is C3HF7, its melting point is 131℃, its boiling point is 16.4℃, it is slightly soluble in water (260mg/L), it is a colorless and odorless gas, its relative molecular mass is 170, its density is about 6 times that of air, it is stored in high-pressure liquefaction, it has good thermal stability and chemical stability, its ozone depletion potential ODP is 0, its greenhouse effect potential GWP is 3500, but it stays in the atmosphere for a short time.

The principle of HFC-227ea gas fire extinguishing is mainly to inhibit chemical chain reaction and partial physical cooling. It can extinguish fire on solid surface, and has good fire extinguishing effect on flammable liquid fire or meltable solid fire, flammable gas fire that can cut off the gas source before extinguishing. There is no pollution loss to the protected property, especially suitable for protecting special items such as precision instruments, data processing centers and precious cultural relics that require fast fire extinguishing speed, non-conductive and non-corrosive.

Toxicity of heptafluoropropane itself:

Around 1994, a relatively comprehensive and systematic study of heptafluoropropane fire extinguishing agent was conducted in China using mice, rabbits, dogs, and human volunteers. The test results show that heptafluoropropane itself is low-toxic or non-toxic, and inhalation can be considered non-toxic. The toxicity characteristics of heptafluoropropane are as follows:

Among them: NOAEL is the concentration at which no adverse reactions are observed. At this concentration, no observable adverse reactions occur in the tested animals. LOA EL is the lowest concentration at which adverse reactions can be observed. It is the lowest test concentration at which adverse reactions occur. (The no toxic reaction (NOAEL) concentration of heptafluoropropane is 9%, and the toxic reaction (LOAEL) concentration is 10.5%)

Although heptafluoropropane itself is toxic, the toxic decomposition products produced during high-temperature fire extinguishing cannot be ignored.

All fires will produce toxic and corrosive combustion products. Experiments have shown that heptafluoropropane decomposes at 600°C. As the temperature rises and the residence time increases, the pyrolysis reaction intensifies and the content of the raw material in the gas products after the reaction gradually decreases. In the study of cracking products, it was found that the main inorganic gas product of the pyrolysis of heptafluoropropane is HF (hydrogen fluoride), and the organic gas products are mainly hexafluoropropylene and pentafluoropropylene, accompanied by the highly toxic gas perfluoroisobutylene. When the temperature rises to 850°C and the residence time is 15 s, the content of perfluoroisobutylene in the organic gas products after the reaction reaches a maximum value of 6.4. The presence of HF (hydrogen fluoride) and perfluoroisobutylene makes heptafluoropropane fire extinguishing agent cause harm to personnel when used in a fire scene. Therefore, in order to reduce the amount of HF produced by the decomposition of heptafluoropropane under high temperature conditions, it is necessary to shorten the spraying time and appropriately increase the fire extinguishing concentration. The "Design Code for Gas Fire Extinguishing Systems" GB50370 stipulates that the fire extinguishing design concentration of heptafluoropropane fire extinguishing systems is less than 10%, and the design spraying time is no more than 10s.

Summary: So is heptafluoropropane harmful to the human body?

When heptafluoropropane is used as a fire extinguishing agent, the fire company strictly follows the "Gas Fire Extinguishing System Design Specification" GB50370 when designing the fire extinguishing concentration. Therefore, heptafluoropropane fire extinguishing agent is safe and non-toxic when used in workplaces where people are often present at the normal design fire extinguishing concentration. However, one thing to note is that when used in places where people are often present and when the concentration may exceed 10.5%, personnel must evacuate within 1 minute; it is generally required that the concentration of heptafluoropropane in the protection area should not exceed 9.0%. Therefore, when a heptafluoropropane fire extinguishing system needs to be set up, it is recommended to find a professional company to design it to ensure the safety of personnel and property.