WO2010001430A2

WO2010001430A2 - Extinguishing agents comprising blends of fluoroiodocarbon and hydrofluorocarbon

Info

Publication number: WO2010001430A2
Application number: PCT/IT2009/000288
Authority: WO
Inventors: Gianluca Indovino
Original assignee: Explosafe International B.V
Priority date: 2008-07-01
Filing date: 2009-07-01
Publication date: 2010-01-07
Also published as: ITRM20080357A1; WO2010001430A3

Abstract

The present invention concerns an agent for extinguishing fire comprising blends of fluoroiodocarbons and hydrofluorocarbons, characterised in that it comprises an amount comprised between 4 and 10% by weight of a fluoroiodocarbon having the following general formula: C_xF_yl_z wherein x ranges between 1 and 3, y ranges between 1 and 7 and z ranges between 1 and 7 and at least a hydrofluorocarbon chosen amongost: trifluoromethane (CHF₃), 1,1,1,2-tetrafluoroethane (CF₃-CH₂F), pentafluoroethane (CF₃CHF₂), 1,1,3,3,3-pentafluoropropane (CHF₂CH₂CF₃) and 1,1,1,2,3,3,3-eptafluoropropane (CF₃CHFCF₃).

Description

EXTINGUISHING AGENTS COMPRISING BLENDS OF FLUOROIODOCARBON AND HYDROFLUOROCARBON

The present invention concerns extinguishing agents comprising blends of fluoroiodocarbons and hydrofluorocarbons.

The invention refers to the field of chemical compositions for extinguishing fires. In a more particular way, the invention refers to extinguishing compositions the use of which can be considered safe for human beings as well as for the environment. In particular, compositions according to this invention have a little effect or no effect in the process of the ozone layer depletion and give a little contribution or no contribution to the process of global warming known as "green-house effect"; but, at the same time, are extremely performant in extinguishing fires.

A fire is the result of the combustion, i.e. an extremely exothermal chemical reaction, of a combustible substance together with oxygen, accompanied by development of heat and flames. In order to give start to such a reaction it is necessary that a certain temperature, called ignition temperature, is reached, beyond that temperature the combustion starts, subsequently developing autonomously. Conditions that can lead to the extinguishment of a fire are essentially three: exhaustion of the combustible substance, exhaustion of oxygen or lowering of the temperature below the ignition temperature.

A fire extinguishment operation therefore can consist in making possible that one or more of the following conditions occur. The operations that are most efficient are the operation of choking, by which oxygen is separated from the combustible substance or its presence in the air is dramatically reduced, and the operation of cooling, consisting in running over the burning material with suitable substances in order to lower its temperature. Generally, extinguishing plants and devices in commerce make use of substances allowing to obtain one or both the described effects.

In particular, to extinguish fires in closed or circumscribed rooms, such as for example rooms of computers, rooms of libraries, oil pumping stations in oil ducts and similar, extinguishing agents comprising halogenated hydrocarbons are preferred. These agents for extinguishing fires comprising halogenated hydrocarbons are not only efficaci for such fires, but cause very little damages or no damages to the room or its content.

Traditionally, these extinguishing agents comprising halogenated hydrocarbons were chosen amongst compounds containing bromine, and were called brominated halogenides. Since the end of the 80s, however, the increasing awareness towards environmental issues and in particular towards the depletion of the stratospheric ozone layer, put the role of chlorofluorocarbons (CFC) and also that of bromine containing halogenocarbons under discussion, and the research moved towards the development of alternative extinguishing agents. The features of such agents, beside that of not to negatively affect the process of ozone depletion, but also that known with the name "green-house effect". This effect is due to the accumulation of gases constituting a screen against heat transfer and produce as a result an undesirable overheating of the surface of the Earth.

Amongst the proposed solutions, a particular interest regarded extinguishing agents comprising hydrofluorocarbons, i.e. only partially fluorine substituted carbons.

European patent N. 439579 discloses a method for extinguishing fire comprising the step of introducing on the flame an extinguishing concentration of one or more compounds chosen from the group consisting of CF₃CHFCF₃, CF₃CH₂CF₃ and CF₃CHFCHF₂, and maintaining the compound concentration until the fire is extinguished.

European patent N. 494987 relates to a process and a composition for extinguishing fire based on a gaseous composition comprising trifluoromethane (CHF₃). European patent N. 557275 discloses extinguishing blends consisting of at least ethane partially substituted with fluorine chosen from the group of pentafluoroethane (CF₃CHF₂) also known as HFC-125 and tetrafluoroethanes (CHF₂-CHF₂ and CF₃-CH₂F), also known as HFC-134 and HFC-134a.

PCT application N. WO 94/20588 discloses an extinguishing agent comprising at least a fluoroiodocarbon, alone or in combination with additives chosen, amongst the others, amongst hydrofluorocarbons. In particular, amongst fluoroiodocarbons, the application also provides for: trifluoroiodomethane (CF₃I), 1,1,1 ,2,3,3,3-eptafluoro-2-iodopropane (CF₃CFICF₃), and 1 ,1 ,2,2,3,3,3-eptafluoro-i-iodopropane (CF₃CF₂CF₂I), while amongst hydrofluorocarbons also provides for: pentafluoroethane (CF₃CHF₂) and 1 ,1 ,1 ,2,3,3,3-eptafluoropropane (CF₃CHFCF₃). In the disclosure, however, this document does not cite specific examples of blends based on these compounds, nor discloses preferred ranges of concentration.

At last, the publication Wright Laboratory N. WL-TR-96-3067 with title "Fluoroiodide blends as streaming agents: selection criteria and cup- burner results", by Robert E. Tapscott, et al., June 1995, trifluoroiodomethane (CF3I) is identified as the more promising extinguishing fluoroiodocarbon and its extinguishing features are inspected in blends together with different hydrofluorocarbons, amongst which in particular 1 ,1,1 ,2,3,3,3-eptafluoropropane (CF₃CHFCF₃), also known as HFC-227ea, and pentafluoroethane (CHF₂CF₃), also known as HFC-125.

In this context is provided the solution according to the present invention, with the aim of providing the optimal composition of extinguishing blends of fluoroiodocarbons and hydrofluorocarbons. The aim of the present invention is therefore that of providing extinguishing agents comprising blends of fluoroiodocarbons and hydrofluorocarbons allowing to overcome the limits of the solutions according to the prior art and to obtain the technical results previously disclosed. A further aim of the invention is that said agents can be obtained with substantially limited costs, as far as both production costs and management costs are concerned.

Not least aim of the invention is that of providing extinguishing agents safe and reliable.

It is therefore a specific object of the present invention an agent for extinguishing^' fire comprising blends of fluoroiodocarbons and hydrofluorocarbons, comprising an amount comprised between 4 and 10% by weight of a fl uoroiodocarbon having the following general formula: C_xFyI₂ wherein x ranges betweeni and 3, y ranges between 1 and 7 and z ranges betweeni and 7 and at least a hydrofluorocarbon chosen amongost: trifluoromethane (CHF₃), 1,1,1,2-tetrafluoroethane (CF₃-CH₂F), pentafluoroethane (CF₃CHFa), 1 ,1 ,3,3,3-pentafluoropropane (CHF₂CH₂CF₃) and 1,1,1,2,3,3,3-eptafluoropropane (CF₃CHFCF₃).

Preferably, according to the invention, said fluoroiodocarbon is C₃F₇I and is present inside the blend in an amount comprised between 5 and 10% by weight, or is CF₃I and is present inside the blend in an amount comprised between 5 and 7,5% by weight. Still more preferably, according to the invention, said fluoroiodocarbon is C₃F₇I and is present inside the blend in an amount comprised between 5,5 and 6% by weight and said hydrofluorocarbon is 1 ,1 ,1 ,2,3,3,3-eptafluoropropane (CF₃CHFCF₃), or said fluoroiodocarbon is C₃F₇I and is present inside the blend in an amount comprised between 9 and 10% by weight and said hydrofluorocarbon is pentafluoroethane, or said fluoroiodocarbon is CF₃I and is present inside the blend in an amount comprised between 5 and 5,5% by weight and said hydrofluorocarbon is 1,1,1,2,3,3,3-eptafluoropropane (CF₃CHFCF₃) or again said fluoroiodocarbon is CF₃I and is present inside the blend in an amount comprised between 7 and 7,5% by weight and said hydrofluorocarbon is pentafluoroethane.

In a particularly preferred embodiment of the invention, said agent for extinguishing fire comprises an amount comprised between 4,5 and 5,5% by weight of C₃F₇I, between 0 and 65% (still more preferably between 50 and 55%) by weight of pentafluoroethane, between 30 and 95% (still more preferably between 38 and 45%) by weight of 1 ,1 ,1 ,2,3,3,3-eptafluoropropane (CF₃CHFCF₃) and between 0 and 5% (still more preferably between 0,5 and 1 ,5%) by weight of a detoxifying agent, preferably oleic acid.

A second and a third specific object of the present invention are respectfully a^' method for extinguishing fires wherein the previoulsy defined agent is used in a total floding system and a method for extingishing fires wherein said agent is used in a portable extinguishing system.

The invention will be disclosed in the following for illustrative, non limitative purpose, with reference to the enclosed drawings, wherein:

- figure 1 shows a chart of the extinguishing concentration of the blend of example 1 as obtained according to test results compared with the values of concentration as determined according to theory for the same blend,

- figure 2 shows a chart of the extinguishing concentration of the blend of example 2 as obtained according to test results compared with the values of concentration as determined according to theory for the same blend,

- figure 3 shows a chart of the extinguishing concentration of the blend of example 3 as obtained according to test results compared with the values of concentration as determined according to theory for the same blend, and - figure 4 shows a chart of the extinguishing concentration of the blend of example 4 as obtained according to test results compared with the values of concentration as determined according to theory for the same blend.

Tests were performed using the test named "cup burner", i.e. the extinguishment test accepted by the US NFPA - National Fire Protection Association (NFPA 2001 Standard on Clean Agent Fire Extinguishing Systems, Ed. 2004) and also defined according to ISO norms - International Standard Organization - (ISO 14520-1 : 2006 on Gaseous fire-extinguishing systems - Physical properties and system design. Part 1: General Requirements). The "cup burner" test is also one of the most common tests for evaluating the extinguishing power of the agents proposed in order to replace Halon 1301 and Halon 1211.

The cup-burner apparatus consists in a vertical conduit made of glass, inside which a little burner is placed filled with a liquid fuel (generally n-heptane, with a purity of not less than 99%), and a flux rectifier, i.e. a device maintaining a uniform non turbulent vertical flux at the base of the vertical conduit. The test consists in igniting the fuel that is coming into the measure instrument at its boiling temperature. Once it is ignited, it is put in contact with a flow consisting of a blend of air and extinguishing agent, in an increasing percentage until the extinguishment of the flame. The gas concentration in the moment when it is possible to state that the flame is extinguished is defined as the extinguishing concentration for that specific fuel.

In this case, experimental tests were performed at environment temperature of the laboratory wherein tests were performed (about 21⁰C). Heptane was provided by a vessel allowing for the liquid fuel level regulation in the burner. Air was provided as compressed natural air filtered by a compressor intaking air from the exterior. The air flow feed was set at 25 NL/min and constantly measured with a flowmeter.

The extinguishing agent was added to the air flow step by step; after each change of the flow of the extinguishing agent, the flame was observed for a period of time not shorter than 8 seconds, before proceeding to the subsequent increase of the flow. The amount of extinguishing agent added to the air flow was increased step by step until the extinguishment of the flame and at that point the volume percentage of the extinguishing agent was determined.

In case one of the components of the blend that was studied is in liquid phase at environment conditions, a bath of water was used in order to reach a temperature higher than that of the boiling point of the blend so that it could be provided to the flame in a vapour phase.

The concentration of the extinguishing agent was determined by evaluating the oxygen concentration in the blend of air/agent using an oxygen analyser based on a paramagnetic sensor (Servomex 1800). In particular, since dry atmospheric air consists of 20,95% mol of oxygen, the concentration of an ideal gas agent in dilution can be calculatedthrough the following equation: %agent = (1-%O₂/20,95)-100

At least five measures of the individual extinguishing value of each extinguishing agent were taken and the average of such values was considered as the final cup-burner value i.e. as the extinguishing concentration of the extinguishing agent under examination.

Example 1. Blends of HFC-227ea and C₃F₇I

Through the cup-burner test the extinguishing concentration was determined of blends of HFC-227ea and C₃F₇I (eptafluoroiodopropane), containing different percentage of fluoroiodocarbon in the range from 0% to 15%.

Table 1 shows some features of the comounds of the blend.

Table 1

Starting from the values of extinguishing concentration of the pure compounds, the expected theoretical trend of the extinguishing concentration of the blend of the two components is represented by the following equation: y = -0.037X + 6,7 R² = 1 wherein: y is the extinguishing concentration of the blend, expressed as % (in volume); x is the composition of C₃F₇I, expressed as % (by weight).

Experimental tests were performed for the following compositions Of C₃F₇I: 0%, 2,5%, 5%, 7,5%, 10% and 15%.

Table 2 shows the composition of the components, the related expected value of extinguishing concentration for the blend and the experimentally determined value of extinguishing concentration, (table follows) Table 2

Figure 1 shows an illustrative chart of the obtained experimental results compared to theoretical values.

Example 2. Blends of HFC-125 and CgF₇J

Through the cup-burner test the extinguishing concentration was determined of blends of HFC-125 and C₃F₇I (eptafluoroiodopropane), containing different percentage of the fluoroiodocarbon in the range from 0% tθ 15%.

Table 3 shows some features of the components of the blend. Table 3

Starting from the values of extinguishing concentration of the pure compounds, the expected theoretical trend of the extinguishing concentration of the blend of the two components is represented by the following equation: y = -0,067x + 9,7 R² = 1 wherein: y is the extinguishing concentration of the blend, expressed as % (in volume); x is the composition of C₃F₇I, expressed as % (by weight).

Table 4 shows the composition of the components, the related expected value of extinguishing concentration for the blend and the experimentally determined value of extinguishing concentration. Table 4

Figure 2 shows an illustrative chart of the obtained experimental results compared to theoretical values.

Example 3. Blends of HFC-227ea and CFaI

Through the cup-burner test the extinguishing concentration was determined of blends of HFC-227ea and CF₃I (iodo-trifluoromethane), containing different percentage of fluoroiodocarbon in the range from 0% to 20%.

Table 5 shows some features of the components of the blend.

Table 5

Starting from the values of extinguishing concentration of the pure compounds, the expected theoretical trend of the extinguishing concentration of the blend of the two components is represented by the following equation: y = -0,052x + 8,4 R² = 1 wherein: y is the extinguishing concentration of the blend, expressed as % (in volume); x is the composition of CF₃I, expressed as % (by weight).

Experimental tests were performed for the following compositions Of CF₃I: 0%, 2,5%, 5%, 7,5%, 10%, 15% and 20%. Table 6 shows the composition of the components, the related expected value of extinguishing concentration for the blend and the experimentally determined value of extinguishing concentration. Table 6

Figure 3 shows an illustrative chart of the obtained experimental results compared to theoretical values.

Example 4. Blends of HFC-125 and CFsI

Through the cup-burner test the extinguishing concentration was determined of blends of HFC-125 and CF₃I (iodo-trifluoromethane), containing different percentage of fluoroiodocarbon in the range from 0% to 15%.

Table 7 shows some features of the components of the blend.

Table 7

Starting from the values of extinguishing concentration of the pure compounds, the expected theoretical trend of the extinguishing concentration of the blend of the two components is represented by the following equation: y = -0,065x + 9,7 R² = 1 wherein: y is the extinguishing concentration of the blend, expressed as % (in volume); x is the composition of CF₃I, expressed as % (by weight).

Experimental tests were performed for the following compositions Of CF₃I: 0%, 2,5%, 5%, 7,5%, 10%, 15% and 20%.

Table 8 shows the composition of the components, the related expected value of extinguishing concentration for the blend and the experimentally determined value of extinguishing concentration.

Table 8

Figure 4 shows an illustrative chart of the obtained experimental results compared to theoretical values.

Example 5. Blends of HFC-125, HFC-227ea and CaF₇I

Through the cup-burner test the extinguishing concentration was determined of blends of HFC-125, HFC-227ea and C₃F₇I, respectively in an amount of 54%, 41% and 5% by weight.

Table 9 shows some features of the components of the blend.

Table 9

Starting from the values of extinguishing concentration of the pure compounds, the expected extinguishing concentration of the three- component blend is 8,8% in volume.

Experimental tests were performed that allowed on the contrary to determine a lower extinguishing concentration of 8,7% in volume.

Example 6. Blends of HFC-125. HFC-227ea. CaF₇I and oleic acid

Through the cup-burner test the extinguishing concentration was determined of blends of HFC-125, HFC-227ea, C₃F₇I and oleic acid, respectively in an amount of 52,5%, 41 ,5%, 5% and 1% by weight.

Table 10 shows some features of the components of the blend.

Table 10

Starting from the values of extinguishing concentration of the pure compounds, the expected extinguishing concentration of the three- component blend is 8,7% in volume.

Experimental tests were performed that allowed on the contrary to determine a lower extinguishing concentration of 8,2% in volume.

The present invention was described for illustrative, non limitative purposes, according to its preferred embodiments, but it is intended that variations and/or modifications can be made by the skilled in the art without escaping the correspondent scope of protection, as defined in the enclosed claims.

Claims

1. Agent for extinguishing fire comprising blends of fluoroiodocarbons and hydrofluorocarbons, characterised in that it comprises an amount comprised between 4 and 10% by weight of a fluoroiodocarbon having the following general formula: C_xF_yI₂ wherein x ranges betweeni and 3, y ranges between 1 and 7 and z ranges between 1 and 7, and at least a hydrofluorocarbon chosen amongost: trifluoromethane (CHF₃), 1 ,1 ,1 ,2-tetrafluoroethane (CF₃-CH₂F), pentafluoroethane (CF₃CHF₂), 1 ,1 ,3,3,3-pentafluoropropane

(CHF₂CH₂CF₃) and 1 ,1 ,1 ,2,3,3,3-eptafluoropropane (CF₃CHFCF₃).

2. Agent for extinguishing fire according to claim 1 , characterised in that said fluoroiodocarbon is C₃F₇I and is present inside the blend in an amount comprised between 5 and 10% by weight.

3. Agent for extinguishing fire according to claim 1 , characterised in that said fluoroiodocarbon is CF₃I and is present inside the blend in an amount comprised between 5 and 7,5% by weight.

4. Agent for extinguishing fire according to claim 1 , characterised in that said fluoroiodocarbon is C₃F₇I and is present inside the blend in an amount comprised between 5,5 and 6% by weight and said hydrofluorocarbon is 1,1 ,1 ,2,3,3,3-eptafluoropropane (CF₃CHFCF₃).

5. Agent for extinguishing fire according to claim 1 , characterised in that said fluoroiodocarbon is C₃F₇I and is present inside the blend in an amount comprised between 9 and 10% by weight and said hydrofluorocarbon is pentafluoroethane.

6. Agent for extinguishing fire according to claim 1 , characterised in that said fluoroiodocarbon is CF₃I and is present inside the blend in an amount comprised between 5 and 5,5% by weight and said hydrofluorocarbon is 1 ,1 ,1 ,2,3,3,3-eptafluoropropane (CF₃CHFCF₃).

7. Agent for extinguishing fire according to claim 1 , characterised in that said fluoroiodocarbon is CF₃I and is present inside the blend in an amount comprised between 7 and 7,5% by weight and said hydrofluorocarbon is pentafluoroethane.

8. Agent for extinguishing fire according to claim 1 , characterised in that it comprises an amount comprised between 4,5 and 5,5% by weight of C₃F₇I, between 0 and 65% by weight of pentafluoroethane, between 30 and 95% by weight of 1 ,1 ,1,2,3,3,3-eptafluoropropane (CF₃CHFCF₃) and between 0 and 5% by weight of a detoxifying agent.

9. Agent for extinguishing fire according to claim 8, characterised in that said detoxifying agent is oleic acid.

10. Agent for extinguishing fire according to claim 9, characterised in that it comprises an amount comprised between 4,5 and 5,5% by weight of C₃F₇I₁ between 50 and 55% by weight of pentafluoroethane, between 38 and 45% by weight of 1 ,1 ,1 ,2,3,3,3-eptafluoropropane (CF₃CHFCF₃) and between 0,5 and 1 ,5% by weight of oleic acid.

11. Method for extinguishing fires wherein the agent according to claims 1-10 is used in a total floding system.

12. Method for extinguishing fires wherein the agent according to claims 1-10 is used in a portable extinguishing system.