Patent Description:
Halon <NUM> (bromotrifluoromethane, CF<NUM>Br) has frequently been employed as a fire suppression agent. However, production of this agent was banned in <NUM> due to its high ozone depleting potential. There is therefore a desire to replace Halon <NUM> with more environmentally friendly fire suppression agents. A promising alternative to Halon <NUM>, CF<NUM>I (trifluoroiodomethane), failed a key fire test and can be subject to decomposition during use. A solution must be found that will improve the stability of the alternative fire suppression agents. <CIT> discloses fire suppressing mixtures containing an organic suppressant, a halogen element and an organic compound. <CIT> discloses fire extinguishing compositions containing trifluoroiodomethane and carbon dioxide. <CIT> and <CIT> disclose refrigerant compositions.

This disclosure relates to fire suppression compositions comprising blends of CF<NUM>l and CO<NUM> as set out in claim <NUM>.

The CF<NUM>l is present in an amount from <NUM> to <NUM> mol. %, e.g. <NUM> mol. % to <NUM> mol. %, <NUM> mol. % to <NUM> mol. %, <NUM> to <NUM> mol. %, or <NUM> to <NUM> mol. %, based on the total moles of CF<NUM>l and CO<NUM> present in the fire suppression composition.

The amount of CF<NUM>l, expressed as a percentage of the total amount of CF<NUM>I and CO<NUM> in the fire suppression compositions, may also be expressed in weight %.

In a further aspect of the present disclosure, the CF<NUM>l is present in an amount of <NUM> weight% to <NUM> weight%, based on the total weight of CF<NUM>l and CO<NUM> present in the fire suppression composition.

The CF<NUM>l may be present in an amount of from <NUM> weight% to <NUM> weight%, or <NUM> weight% to <NUM> weight%, based on the total weight of CF<NUM>l and CO<NUM> present in the fire suppression composition.

As the amount of CF<NUM>l is expressed as proportion of the total of CF<NUM>I and CO<NUM>, it will be understood that the percentage of CO<NUM> (also expressed as a proportion of the total) is the remainder of this total (i.e. <NUM> minus the percentage of CF<NUM>I). Where the composition consists of, or consists essentially of, CF<NUM>l and CO<NUM>, these proportions will also be applicable to the composition as a whole. Fire suppression compositions comprising such blends of CF<NUM>I and CO<NUM>, e.g. those with molar ratios of CF<NUM>l to CO<NUM> of from <NUM>:<NUM> to <NUM>:<NUM>, or <NUM>:<NUM> to <NUM>:<NUM> form a further aspect of this disclosure.

In addition to CF<NUM>l and CO<NUM>, the fire suppression compositions as disclosed herein can further comprise one or more additional components. The additional components may be selected from a gas (e.g. an inert gas), an additional fire suppressant compound, odorants, or combinations thereof.

The total amount of additional components, if present, is up to <NUM> weight%, based on the total weight of the fire suppression composition. The CF<NUM>l and CO<NUM> (in total) is present in an amount of at least <NUM> weight%, based on the total weight of the fire suppression composition.

The total amount of additional components present in the fire suppression composition may be up to <NUM> weight%, up to <NUM> weight%, up to <NUM> weight%, up to <NUM> weight% or up to <NUM> weight%, (e.g. from <NUM> weight% up to these limits) based on the total weight of the fire suppression composition. The remainder is CF<NUM>l and CO<NUM>, based on the total weight of the fire suppression composition, e.g. at least <NUM>, at least <NUM>, at least <NUM>, at least <NUM>, at least <NUM> or at least <NUM> weight% of the fire suppression composition is the CF<NUM>l/CO<NUM> blend. In some aspects, the total amount of additional components present in the fire suppression composition is up to <NUM> weight% or up to <NUM> weight%, e.g. <NUM> weight% to <NUM> weight % or <NUM> weight % to <NUM> weight % (e.g. at least <NUM>, at least <NUM>, e.g. <NUM>-<NUM> or <NUM>-<NUM> weight% of the fire suppression composition is the CF<NUM>l/CO<NUM> blend).

The additional components, if present, may be one or more gases, e.g. an inert gas, or a propellant. Examples of suitable gases include nitrogen, argon, helium and neon, and combinations thereof.

The optional gas may be present in an amount of up to <NUM> weight%, based on the total weight of the fire suppression composition. For example, the gas may be present in an amount of up to <NUM> weight%, up to <NUM> weight%, up to <NUM> weight%, up to <NUM> weight%, up to <NUM> weight%, up to <NUM> weight%, up to <NUM> weight%, up to <NUM> weight% or up to <NUM> weight%, based on the total weight of the fire suppression composition. If present, a lower limit for the gas may be <NUM> weight %.

The additional component, if present, may be an additional fire suppressant compound, i.e. one that is not CF<NUM>l or CO<NUM>.

The additional fire suppressant compound, if present, may be present in an amount of up to <NUM> weight%, based on the total weight of the fire suppression composition. For example, the total amount of additional fire suppressant compound present in the fire suppression composition may be up to <NUM> weight%, up to <NUM> weight%, up to <NUM> weight%, up to <NUM> weight% or up to <NUM> weight% based on the total weight of the fire suppression composition. If present, a lower limit for the additional suppressant may be <NUM> weight %.

The additional component, if present, can be an odorant. Examples of odorants include compounds which include one or more carbon-carbon double bonds, and/or compounds which are aromatic. The odorant compounds may further include a hydroxyl group, an iodine group, or both.

The odorant compound, if present, may be present in an amount of up to <NUM> weight% based on the total weight of the fire suppression composition. For example, the odorant may be present in an amount of up to <NUM> weight%, up to <NUM> weight%, up to <NUM> weight%, up to <NUM> weight%, up to <NUM> weight%, up to <NUM> weight%, up to <NUM> weight%, up to <NUM> weight% or up to <NUM> weight%, based on the total weight of the fire suppression composition. If present, a lower limit for the odorant may be <NUM> weight %.

The present disclosure also provides a device, e.g. a fire extinguisher, fire suppression device, or storage device, comprising a fire suppression composition as herein described.

Also disclosed is a device, e.g. a fire extinguisher, fire suppression device, or storage device, comprising at least two separate containers, wherein the first container comprises CF<NUM>l and the second container comprises CO<NUM>. The proportions of the CF<NUM>l and the CO<NUM> are as described herein. The contents of the containers can be combined immediately prior to use to produce a fire suppression composition as herein described. As would be understood, the first and/or second container can comprise one or more additional components (e.g. one or more additional components as herein described) or any additional components can be stored in a further container or containers.

Disclosed is a fire suppression system or device comprising a fire suppression composition as herein described, or the components thereof. The fire suppression system can comprise a fire suppression composition herein described and a dispensing component (such as one or more nozzles that disperse the fire suppression composition). In an alternative aspect, the fire suppression system can contain: (i) two separate containers, wherein the first container comprises CF<NUM>l and the second container comprises CO<NUM>, and (ii) a combining and dispensing component which is configured to combine the contents of the separate containers to form a fire suppression composition as herein described, and then dispense said resulting fire suppression composition.

Also disclosed is a method for extinguishing a fire comprising using a fire suppression composition as herein described.

Disclosed is a method for preparing a fire suppression composition as herein described, said method comprising combining CF<NUM>l and CO<NUM> such that CF<NUM>l is present in an amount as herein described in relation to the total amount of CF<NUM>l and CO<NUM>. The method may comprise the steps of (i) providing CF<NUM>I, (ii) providing CO<NUM> and (iii) combining CF<NUM>l and CO<NUM> such that CF<NUM>l is present in an amount as herein described in relation to the total amount of CF<NUM>l and CO<NUM>. The method can further comprise the additional step of adding one or more additional components as herein described.

In some aspects, the fire suppression composition of the present disclosure consists of, or consists essentially of, CF<NUM>I and CO<NUM> in the proportions described herein.

CF<NUM>l is an environmentally friendly alternative to fire suppression agents like Halon <NUM> because CF<NUM>l has a lower ozone depletion potential. The lower ozone depletion potential is due to the lower stability of the molecule. However, the lower stability (or the increased tendency to degrade) presents a challenge for use of CF<NUM>l or blends containing CF<NUM>l as a fire suppression agent. The lower stability has discouraged the use of CF<NUM>l in fire suppression applications as it can decompose, thus reducing its efficacy. The present disclosure involves addition of CO<NUM> to the CF<NUM>l, which has been found to improve stability of CF<NUM>I.

When released, the CO<NUM> is able to remove a large amount of heat from its surroundings (i.e. has a high heat capacity). This temperature reduction can reduce the severity of the fire, as well as reducing the decomposition rate of CF<NUM>l, maximizing the available CF<NUM>l present when the fire suppression composition is used to extinguish a fire.

The presence of CO<NUM> in the fire suppression composition can reduce the temperature of the atmosphere in the space to be protected to below <NUM> (<NUM>°F), e.g. to below <NUM>, to below <NUM>, to below <NUM>, to below <NUM>, to below <NUM>, or to below <NUM> (<NUM> °F).

CO<NUM> is a physically acting fire suppression agent and CF<NUM>l is a chemically acting agent. Combining these two different types of agent as described herein results in a synergistic combination. More specifically, the blends of CO<NUM> and CF<NUM>l as disclosed herein have been shown to be a synergistic combination. The combination of these two components has surprisingly resulted in a fractional inerting composition number of less than the sum of the two components when measured separately. The effect of this is that the combination of these two components has an enhanced ability to extinguish a fire than the two components would have had if used separately in the same amount.

It has also been found that fire suppression compositions according to the present disclosure can have a vapor pressure in a similar range as that of conventional fire suppression agents such as Halon <NUM>. The vapor pressure allows the fire suppression composition to be used in conventional hardware such as preexisting fire extinguishing containers and devices.

The present disclosure will now be further described by way of the following non-limiting examples.

Testing was carried out against propane-air explosions in a <NUM> sphere. The most explosive propane-air mixture is <NUM>% propane in air. This concentration was therefore used to assess the relative performance of extinguishing agents and blends thereof.

The sphere was evacuated. Whilst monitoring the pressure transducer, propane was added to a pressure of <NUM> atm (<NUM>% in the final mix). The agent or agents were added at the desired concentration. Air was then added to raise the pressure in the sphere to <NUM> atm. A fan can then be used to ensure that all the gases are mixed homogeneously throughout the sphere. A spark was ignited using a center point spark ignition and the pressure rise was monitored by a data logger. A pressure rise of 1psi or lower is designated as a pass. The standards used for inerting testing are:.

When assessing blends of components, the concept of fractional inerting contribution is used. This is defined as: <MAT> Where Ci is the concentration of component i
And ICi is the inerting concentration of component i.

Thus, inerting should be attained when FIC = <NUM> (i.e. the sum of individual concentrations has reached the overall required amount to achieve inerting). It therefore follows that if inerting is achieved at FIC less than <NUM>, then the blend is more effective than the sum of its components. In other words, the blend is exhibiting synergy.

Blends of CF<NUM>l and CO<NUM> were evaluated and it was found that successful inerting results were found at FIC values of lower than <NUM>:
In Table I and II, values expressed in psig are to be converted in KPa, with <NUM> psig=<NUM> kPa.

Examples <NUM> to <NUM> and <NUM> to <NUM> are outside the scope of the present claims.

<FIG> shows the results of these inerting tests on CF<NUM>/CO<NUM> blends, in which:.

For all three parameters, a lower value relative to Halon <NUM> is desired. Examining <FIG> in detail:.

These results show the equivalent weight of CF<NUM>l/CO<NUM> blend to Halon <NUM> to achieve same inerting efficiency. The <NUM>/<NUM> by mol. % CF<NUM>l/CO<NUM> blend showed inerting equivalent to Halon <NUM> at only <NUM>. 03x weight, <NUM>. 97x volume and <NUM> x the relative pressure of a Halon <NUM> system.

As can be seen from Tables I and II above and <FIG>, blends according to the present disclosure show a synergistic effect between the CF<NUM>l and CO<NUM> in the blend. Examples <NUM>-<NUM> show a particularly good synergistic effect, coupled with an acceptable vapor pressure/temperature characteristics. Examples <NUM>-<NUM> show a synergistic effect, and these examples have improved vapor pressure/temperature characteristics.

A cup burner is a relatively simple apparatus used to measure the extinguishing concentration of a fire extinguishing agent, or in this case, a blend of two agents. The cup burner test is quick to perform, uses little extinguishing agent and gives repeatable results. It is regarded as an industry standard test for evaluating fire extinguishing agents. This test was carried out to investigate the equivalent weight of CF<NUM>l/CO<NUM> blend to Halon <NUM> to achieve same efficiency.

A flame was established in a cup, situated in the centre of a glass tube. There was an airflow in the tube to feed the flame. Into this airflow the extinguishing agent was introduced, and its concentration was gradually increased until the flame was extinguished. The agent concentration was measured, and the test was then repeated.

The results are shown in Table III below:.

<FIG> shows the results of cup burner tests, in which the extinguishing concentration is plotted as a function of the proportion of CF<NUM>l in the blend. The fact that the data points are not in a straight line but show considerable curvature: looking at the third column, just <NUM>% CF<NUM>l reduced the quantity of CO<NUM> required by almost half (<NUM>% → <NUM>%). This is clear evidence of synergy. This plot can be used to determine optimal blends, particularly if other factors such as such as liquid density and vapour pressure are considered.

The <NUM> mol% CF<NUM>l <NUM> mol% CO<NUM> blend ("56CF<NUM>I:44CO<NUM>") was evaluated to determine whether it could fit into the same Halon <NUM> container.

Pressure was monitored over a range of temperatures with certain fill densities of the CF<NUM>l/CO<NUM> blend. The results are shown in <FIG> which plots pressure over a range of temperatures, in which:.

As shown in <FIG>, 56CF<FIG>I:44CO<NUM> blend with <NUM>. 3x and <NUM>. 5x fill density has very similar pressure-temperature behaviour to that of Halon <NUM> HRD normal fill and max fill, respectively. In <FIG>, values expressed in psig are to be converted in KPa, with <NUM> psig=<NUM> kPa.

The above examples demonstrate that blends according to the present disclosure provide a "drop-in" replacement for Halon <NUM>, where relative mass, relative volume, and relative pressure are optimized.

References to "comprises" and/or "comprising," should be understood to also encompass "consist(s) of", "consisting of", "consist(s) essentially of" and "consisting essentially of".

Claim 1:
A fire suppression composition comprising CF<NUM>l and CO<NUM>,
wherein said CF<NUM>l is present in an amount of from <NUM> mol.% to <NUM> mol.%, based on the total moles of CF<NUM>l and CO<NUM> present in the fire suppression composition; and
wherein the total amount of additional components, if any, in said fire suppression composition is up to <NUM> weight%, based on the total weight of the fire suppression composition.