RU2790715C1 - Gas fire-extinguishing agent - Google Patents

Abstract

FIELD: gas fire extinguishing means.

SUBSTANCE: invention can be used for extinguishing fires of classes A2, B, C and E, phlegmatization of explosive gaseous media, as well as for localizing fires of class A1. The gas extinguishing composition contains from 1% of the mass. up to 5 wt.% dibromomethane; the rest are ethylene-bonded fluorocarbon with general formula C₆F₁₂O_n, where n=0 or 1, or a mixture of such fluorocarbons, or flourated alkane with general formula C_nF_2n+1H, where n=1, 2, 3. The invention provides fire extinguishing efficiency at the level of bromine-containing freons, significantly lower toxicity than existing analogues, does not contain combustible substances, and its components either fully meet modern environmental requirements, that is, they have zero ozone depletion potential, a short lifetime in the atmosphere and a low global warming potential, or have a greenhouse effect, but are used in a much smaller volume than in similar gas fire extinguishing compositions.

EFFECT: fire extinguishing efficiency at the level of bromine-containing freons, significantly lower toxicity than existing analogues, does not contain combustible substances.

1 cl, 3 tbl

Description

The invention relates to combined gas fire extinguishing means and can be used for volumetric and local area extinguishing of fires of classes A2, B, C and E and phlegmatization of explosive gaseous media in a closed volume, as well as for localizing fires of class A1.

In accordance with modern environmental requirements established by the UN Montreal Protocol on Substances that Deplete the Earth's Ozone Layer, gaseous fire extinguishing agents (GOFS) must have a zero ozone depleting potential (ODP) and a low global warming potential (GWP). ), achieved due to the short lifetime of matter in the atmosphere (less than 181 days). After the ratification by the Russian Federation of the Kigali Amendment to the Montreal Protocol on March 25, 2020, Russian production should be gradually reduced (by 85% by 2036) of the main reactive gaseous fire extinguishing agents - fluorinated alkanes CF ₃ H, C ₂ F ₅ H and C ₃ F ₇ H, having ODP=0, but being long-lived greenhouse gases (atmospheric lifetime from 29 to 270 years, global warming potential from 3220 to 14800). The present invention is aimed at reducing the use of greenhouse gases in fire extinguishing by creating a highly effective gaseous fire extinguishing composition, in which greenhouse and ozone-depleting components are either completely absent or their content is significantly reduced compared to existing fire extinguishing agents, less toxic than existing analogues, and not inferior to them for fire extinguishing efficiency.

The prototype of the claimed invention is patent RU 2310488 C2, publ. 11/20/2007 Fire extinguishing composition, IPC A62D1 / 06, which proposes to use as a gas fire extinguishing agent a mixture consisting of ethyl bromide 30-70 wt.%. and iodine-containing fluorocarbon C ₁ - C ₃ with 1-2 iodine atoms 70-30% of the mass. Such a mixture has a high fire-extinguishing efficiency (from 3.0 to 4.8% by volume with respect to the combustion of n-heptane). But, since ethyl bromide has an atmospheric lifetime of 183 days, it is not a short-lived substance, due to the presence of a bromine atom in the molecule, it has a non-zero ODP, and is subject to a production ban in accordance with the UN Montreal Protocol on Substances that Deplete the Earth's Ozone Layer. C ₂ H ₅ Br is a combustible substance (the concentration limits of flame propagation in air are from 6.5% vol. to 9.5% vol.); cases are known when non-combustible mixtures containing ethyl bromide ignited under certain conditions (Kopylov SN, Kopylov PS, Eltyshev IP Fire Safety of 1, 2 and 2l Refrigerants: Myths and Reality - IOP Conf. Series: Earth and Environmental Science 272 (2019 ), 8 p.). In addition, an iodine-containing hydrofluorocarbon with the declared ratio of components, being fed into the protected room, will be toxic, since its content in the atmosphere of the room will exceed the minimum threshold of no observed toxic effect by more than 2 times (NOAEL, No Observable Adverse Effect Level, for iodinated fluorocarbons). is 0.4% vol. or less), and the use of a fire extinguishing composition is impractical for rooms with the presence of people.

The essence of the claimed invention lies in the fact that a mixture of dibromomethane with fluorinated alkanes with the general formula C _n F _2n+1 H, where n=1,2,3 or fluorinated hydrocarbons containing a double bond with the general formula C ₆ F ₁₂ O _n , where n = 0 or 1, while the proportion of dibromomethane in the mixture is from 1% wt. up to 5% wt.

The inventive composition provides the values of fire extinguishing concentration at the level of the prototype (see Table. 1, 2). Unlike ethyl bromide proposed in patent RU 2310488 C2, dibromomethane is a non-combustible gas, the lifetime in the atmosphere of which is 16.5 days, that is, it is a short-lived substance in atmospheric conditions that fully meets modern environmental requirements and is not subject to the restrictions of the Montreal protocol. It also provides significantly better characteristics of the fire extinguishing composition in terms of toxicity compared to the fire extinguishing compositions adopted for the prototype: the content of CH ₂ Br ₂ in the fire extinguishing composition is selected so that its concentration under the conditions of use does not exceed the NOAEL level for this substance, equal to 0.4% vol. , and the fluorinated components of the proposed composition have NOAEL values that exceed the level of fire extinguishing concentration of the proposed composition (see Tables 2, 3), that is, it is safe for humans when used. Due to the absence of iodine-containing substances in the claimed composition and the low content of the brominated component, its corrosivity is significantly lower than that of the fire extinguishing composition adopted as a prototype.

Table 1

No. p / p The content of components, % wt. fire extinguishing concentration,
% about. _{C2H5Br _} C ₂ F ₄ Br ₂ CF ₃ I C ₂ F ₅ I C ₃ F ₇ I 1 2 3 4 5 6 7 1. 70 - thirty - - 4.6 2. 70 - - thirty - 4.7 3. 70 - - - thirty 4.3 4. 50 - 50 - - 4.2

Table 1 continued

1 2 3 4 5 6 7 5. 50 - - 50 - 4.3 6. 50 - - - 50 3.6 7. thirty - 70 - - 3.8 8. thirty - - 70 - 3.7 9. thirty - - - 70 3.0

Table 2. Fire extinguishing efficiency of the claimed compositions

No. p / p The content of components, % wt. fire extinguishing concentration,
% about. _{CH2Br2 _ CF3} H C ₂ F ₅ H C ₃ F ₇ H (CF ₃ ) ₂ C=CFCF ₂ CF ₃ CF ₃ CF=CFCF(CF ₃ ) ₂ C ₆ F ₁₂ O 1 2 3 4 5 6 7 8 9 1. 1 99 - - - - - 12.0 2. 5 95 - - - - - 8.5 3. 1 - 99 - - - - 9.0 4. 5 - 95 - - - - 5.2 5. 1 - - 99 - - - 6.5 6. 5 - - 95 - - - 3.3 7. 1 - - - 99 - - 3.1 8. 5 - - - 95 - - 2.9 9. 1 - - - - 99 - 3.2 10. 5 - - - - 95 - 3.0 eleven. 1 - - - - - 99 4.0 12. 5 - - - - - 95 3.3

Table 3. Toxicity of the components of the claimed formulations

_{CH2Br2 _ CF3} H C ₂ F ₅ H C ₃ F ₇ H (CF ₃ ) ₂ C=CFCF ₂ CF ₃ CF ₃ CF=CFCF(CF ₃ ) ₂ C ₆ F ₁₂ O NOAEL,
% about. 0.4 50.0 7.5 9.0 9.0-10.0* 9.0-10.0* 10.0

*estimated value, similar to C ₆ F ₁₂ O (lack of solubility in water and fats)

In determining the compliance of the distinctive features of the proposed invention with the criterion of "inventive step", the state of the art for gas fire extinguishing compositions was analyzed. Known gas fire extinguishing composition TFM-18I (SP 485.1311500.2020 Fire protection systems. Automatic fire extinguishing installations. Design norms and rules), which is a gas mixture containing 90% of the mass. trifluoromethane and 10% wt. methyl iodide. The fire extinguishing efficiency of such a composition is low due to the high content of trifluoromethane in it and is 9.5% vol. for n-heptane. Other disadvantages of TFM-18I are its toxicity due to the presence of an iodine-containing substance in concentrations exceeding the threshold of its toxic effects on humans under conditions of use, separation of the mixture during storage under pressure due to a significant difference in the boiling points of the components, as well as a non-zero ODP value of methyl iodide.

Non-zero ozone-depleting potential due to the presence of hydrocarbons containing iodine or bromine atoms in the gas fire extinguishing agent, as well as their high toxicity, are critical shortcomings of GOTV in the following well-known patents: hydrocarbon (from 1 to 98%) with a hydrocarbon in which hydrogen atoms are completely or partially replaced by iodine and fluorine atoms (from 1 to 98%) and propylene (from 1 to 10%); (a mixture of CF ₃ H 1.0 - 2.7 or 25.7 - 99.0% vol. with iodine-containing alkanes C ₁ - C ₂ 1.0 - 33.9 or 89.0 - 99.0% vol. and perfluoroalkanes C ₃ - C ₄ ); WO 94/20588, 15.09.1994 Fluoroiodocarbon blends as CFC and Halon replacements

Known US patent No. 8858820, publ. 10/14/2014 Bromofluorocarbon compositions. This patent proposes to use 2-bromo-3,3,3-trifluoropropene as GOTV. Bromotrifluoropropene is highly toxic under the conditions of use (minimum toxicity threshold No Observed Adverse Effect Level, NOAEL = 0.5% vol. with a minimum fire extinguishing concentration for n-heptane 4.6% vol.). The disadvantage of this GOTV is the high value of the minimum fire extinguishing concentration, due to the fact that the Br atom compensates for the flammability of the fluorinated propene itself (in particular, the closest analogues of 2-bromo-3,3,3-trifluoropropene - trifluoropropene and tetrafluoropropene - are able to burn).

Compositions of partially fluorinated alkenes and partially fluorinated alkenes containing a chlorine atom according to US patent No. 20120240477, publ. 09/27/2012 Compositions comprising 2,3,3,3-tetrafluoropropene, 1,1,2,3-tetra-chloropropene, 2-chloro-3,3,3-trifluoropropene, or 2-chloro-1,1,1, 2-tetrafluoropropane and No. 20130161554, publ. 06/27/2013 Stabilized hydrochlorofluoroolefins and hydrofluoroolefins, although claimed to be used as fire extinguishing agents, were developed primarily as coolants, solvents and foaming agents (the patents do not contain data on their effectiveness as GFFS), and can hardly be used in fire extinguishing, since as a mixture of combustible substances. In addition, their ODP is not equal to zero due to the presence of the chlorine-containing component of the mixture.

Known gas fire extinguishing agent perfluoroethyl-isopropyl ketone (ISO 14520-5:2019 Gas fire extinguishing systems - Physical properties and system design - Part 5: Fire extinguishing composition FK-5-1-12). This substance fully meets modern environmental requirements (ODP=0, lifetime in the atmosphere 5 days, GWP less than 1) and has low toxicity (NOAEL=10% vol.), but its fire extinguishing efficiency is low (the minimum fire extinguishing concentration for n-heptane is 4 .5% vol.).

Thus, the distinguishing features of the invention are new and meet the criterion of "novelty".

The inventive fire extinguishing composition meets the requirements for modern gas fire extinguishing means, and can be used both in automatic volumetric fire extinguishing installations and as a fire extinguishing agent for hand-held fire extinguishers.

The inventive fire extinguishing composition is obtained by mixing the components by mass ratio in the liquid phase.

The claimed fire extinguishing composition is implemented in accordance with the procedure described in SP 485.1311500.2020 Fire protection systems. Automatic fire extinguishing installations. Design norms and rules. Fire extinguishing composition tests for fire extinguishing efficiency are carried out in accordance with GOST R 53280.3-2009 Automatic fire extinguishing installations. Fire extinguishing agents. Part 3. Gas extinguishing agents. Test methods.

Claims (1)

Gas extinguishing composition containing from 1% of the mass. up to 5% wt. _{dibromomethane ; _ _ _} , 2, 3.