AU620687B2

AU620687B2 - Fire extinguishing compositions

Info

Publication number: AU620687B2
Application number: AU49026/90A
Authority: AU
Inventors: Norman Fletcher
Original assignee: Imperial Chemical Industries Ltd
Current assignee: Imperial Chemical Industries Ltd
Priority date: 1989-02-14
Filing date: 1990-02-01
Publication date: 1992-02-20
Anticipated expiration: 2010-02-01
Also published as: JPH02265575A; EP0383443A2; AU4902690A; KR900012640A; EP0383443A3; GB8903334D0

Description

C ~DIYIPI-"I~-

AUSTRALIA

Patents Act COMPLETE SPECIFICATION

(ORIGINAL)

0 ma Class Int. Class Application Number: Lodged: Complete Specification Lodged: Accepted: Published: Priority Related Art: 0 0o o 0 0 so 0 0 0 0 0 0 oto, 00Q 0 Applicant(s): Imperial Chemical Industries PLC Imperial Chemical House, Millbank, London SWIP 3JF, UNITED KINGDOM Address for Service is: 400 000 0 0 0 0 I i t PHILLIPS ORMONDE FITZPATRICK Patent and Trade Mark Attorneys 367 Collins Street Melbourne 3000 AUSTRALIA Complete Specification for the invention entitled: FIRE EXTINGUISHING COMPOSITIONS Our Ref 162385 POF Code: 1453/1453 The following statement is a full description of this invention, including the best method of performing it known to applicant(s): 1 6006 ts-- J, 1 FIRE EXTINGUISHING COMPOSITIONS The present invention relates to fire extinguishing compositions.

In view of the concern surrounding possible damage to the ozone layer by certain halocarbons, a need has arisen to find alternative fire extinguishing compositions.

Accordingly, the present invention provides a fire extinguishing composition consisting essentially of: one or more fire extinguishing compounds selected from bromodifluoromethane (CF HBr), 1-bromo-1,2,2,2tetrafluoroethane (CF3CHFBr), 1-chloro-1,2,2,2-tetrafluoroethane (CF 3 CFHC1) and l,l-dichloro-2,2,2-trifluoroethane (CF3CHC12); optionally a completely halogenated fluorobromo- S alkane(s) and/or fluorobromochloroalkane(s); oo" optionally a coadjuvant agent(s) having a boiling oo point below 0°C; and o00 optionally a gaseous propellant(s).

A further aspect of the present invention provides 0o00 for a method of extinguishing a fire which comprises applying to said fire a fire extinguishing composition consisting essentially of: o""o one or more fire extinguishing compounds selected o. from bromodifluoromethane (CF 2 HBr), 1-bromo-l,2,2,2- 0 0 2 tetrafluoroethane (CF 3 CHFBr), 1-chloro-l,2,2,2-tetrafluoroethane (CF CFHC1) and l,l-dichloro-2,2,2-trifluoroethane

(CF

3 CHC1 2 optionally a completely halogenated fluorobromoalkane(s) and/or fluorobromochloroalkane(s); optionally a coadjuvant agent(s) having a boiling point below 0°C; and optionally a gaseous propellant(s).

The fire extinguishing compositions of the invention may contain a single compound selected from bromodifluoromethane (CF 2 HBr), l-bromo-l,2,2,2-tetrafluoroethane

(CF

3 CHFBr), 1-cltloro-l,2,2,2-tetrafluoroethane

(CF

3 CFHC1) and l,l-dichloro-2,2,2-trifluoroethane

(CF

3 CHC1 2 or they may contain a mixture of two or 39 -1A-

GD

more of these compounds. Of these compounds bromodifluoromethane (CF2HBr) and 1-bromo-l,2,2,2tetrafluoroethane (CF 3 CHFBr) are preferred, bromodifluoromethane (CF 2 HBr) being the most preferred.

In addition to the essential fire extinguishing compound(s), the fire extinguishing compositions of the invention may further comprise one or more fire extinguishing compounds selected from the completely halogenateA fluorobromoalkanes and fluorobromochloroalkanes, such as 1,1,2,2-tetrafluoro-l,2-dibromoethane (CF2Br-CF2Br), dibromodifluoromethane (CF 2 Br 2 bromotrifluoromethane (CF 3 Br), and bromochlorodifluoromethane (CF 2 ClBr). Of these dibromodifluoromethane (CF Br 2 is preferred.

The fire extinguishing compositions of the invention may also comprise one or more coadjuvant agents having a i 'boiling point below 0°C (hereinafter referred to as coadjuvants), which may enhance the effectiveness of the 2 fire extinguishing compositions, e.g. on delivery from a fire extinguishing device. Preferred coadjuvants are the haloalkanes, especially the haloethanes and halomethanes, having a boiling point below 0°C, preferred examples of which are chlorodifluoromethane, 1,1,2,2-tetrafluoroethane and 1,1,1,2-tetrafluoroethane. Coadjuvants may, for example, be advantageously employed when l,l-dichloro- 2,2,2-trifluoroethane (CF 3 CHC1 2 is used as the sole or major fire extinguishing compound in the compositions of the invention, since 1,l-dichloro-2,2,2-trifluoroethane (CF 3 CHC1 2 has a boiling point of 27 0 C, and is therefore a liquid at normal ambient temperatures.

However, the use of coadjuvants in the fire extinguishing compositions of the invention is not essential, particularly where fire extinguishing compounds having a boiling point below 0°C are employed. For example, if bromodifluoromethane (CF 2 HBr) and/or 1-chloro-l,2,2,2tetrafluoroethane (CF 3 CFHC1) are employed as the fire extinguishing compounds, their boiling points (-15 0 C and -12 0 C respectively) are sufficiently low that they may be 39 -2-

GD

L^ h effectively discharged from a fire extinguishing device without the need for a coadjuvant. Even where a fire extinguishing compound having a boiling point above 0°C, such as l,l-dichloro-2,2,2-trifluoroethane (CF 3 CHC1 2 is used, a fire extinguishing composition containing such a compound may be effectively discharged from a fire extinguishing device by employing another fire extinguishing compound(s) in combination therewith which has a boiling point below 0°C. These other fire extinguishing compounds may be selected, for example, from bromodifluoromethane and/or 1-chloro-1,2,2,2-tetrafluoroethane and/or the fully halogenated fluorobromoalkanes and/or fluorobromochloro- S, alkanes. Notwithstanding the above, fire extinguishing compositions containing one or more coadjuvants may be preferred.

The fire extinguishing compositions of the invention will typically comprise one or more gaseous propellants in order to expedite the discharge thereof, e.g. from a fire extinguishing device. Suitable propellants are compounds of low toxicity and high stability, preferred examples of which are nitrogen and carbon dioxide.

Where the fire extinguishing compositions of the invention comprise other compounds in addition to the essential fire extinguishing compound(s), such as Sadditional fire extinguishing compounds selected from the completely halogenated fluorobromoalkanes and fluorobromochloroalkanes and/or coadjuvant agents and/or gaseous propellants, the proportion of the essential fire extinguishing compound(s) may vary within wide limits.

For example, a suitable fire extinguishing composition may comprise from as little as 5% by volume to as much as by volume of the at least one essential fire extinguishing compound(s), based on the total volume of the fire extinguishing composition.

The present invention is now illustrated, but not limited, by the following examples.

39 -3-

GD

i rt EXAMPLE 1 The lowest concentration of the essential fire extinguishing compounds in air sufficient to extinguish a flame was determined using the Cup Burner method (see Fire Technology Vol. 13, No. 4, November 1977, pp 296-315).

A burner supplied with n-heptane was arranged in a glass apparatus to which air was supplied at a linear velocity of about 14 cm/s. The concentration of the fire extinguishing compound in the air was gradually increased until the flame was extinguished.

Table 1 lists the concentration of each fire extinguishing compound in air (volume at the moment of extinction of the flame.

TABLE 1 FIRE EXTINGUISHING CONCENTRATION IN AIR S, COMPOUND (Volume AT POINT OF

EXTINCTION

I

CF

2 HBr

CF

3 CFHC1 7.8

CF

3 CHC1 2 6.3 CF3CFHBr 3.6 EXAMPLE 2 A Committee European Normalisation (CEN) 17B fire was started using 17 litres of n-heptane as the fuel. The fire was extinguished in 4 seconds using 1200 g of 1-chloro-1,2,2,2-tetrafluoroethane discharged in 8 seconds from a 1230 ml Thorn extinguisher by 130 psi of nitrogen.

EXAMPLE 3 A Committee European Normalisation (CEN) 13B fire was started using 13 litres of n-heptane as the fuel. The fire was extinguished in 4.5 seconds using a mixture of 725 g of l,l-dichloro-2,2,2-trifluoroethane 80 g chlorodifluoromethane discharged in 8 seconds from a 760 ml 39 -4-

GD

i ~e 1 I~i~ C i C lll~- lll~ -b- Thorn extinguisher by 130 psi of nitrogen.

EXAMPLE 4 A Committee European Normalisation (CEN) 21B fire was started using 21 litres of n-heptane as the fuel. The fire was extinguished in 6 seconds using a mixture of 1200 g of l,l-dichloro-2,2,2-trifluoroethane 135 g chlorodifluoromethane discharged in 8 seconds from a 1230 ml Thorn extinguisher by 130 psi of nitrogen.

EXAMPLE A Committee European Normalisation (CEN) 13B fire was started using 4 litres of n-heptane as the fuel. The fire was extinguished in 1.5 seconds, after allowing the fire to burn for 20 seconds, using 359 g of bromodifluoromethane discharged from a 1230 ml Thorn extinguisher Scontaining 1258 g of bromodifluoromethane pressurised to 150 psi with nitrogen.

t' .EXAMPLE 6 A Committee European Normalisation (CEN) 21B fire was started using 21 litres of n-heptane as the fuel. The fire was extinguished in 2.0 seconds, after allowing the fire to burn for 60 seconds, using 452 g of bromodifluoromethane discharged from a 1230 ml Thorn extinguisher containing 920 g of bromodifluoromethane pressurised to 100 psi with nitrogen.

So a 0 EXAMPLE 7 A Committee European Normalisation (CEN) 13B fire was started using 4 litres of n-heptane as the fuel. The fire was extinguished in 1.1 seconds, after allowing the 0o fire to burn for 20 seconds, using 360 g of 1-bromo- 1,2,2,2-tetrafluoroethane discharged from a 1230 ml Thorn extinguisher containing 1510 g of 1-bromo-l,2,2,2-tetrafluoroethane pressurised to 150 psi with nitrogen.

EXAMPLE 8 A Committee European Normalisation (CEN) 21B fire was started using 21 litres of n-heptane as the fuel. The fire was extinguished in 2.2 seconds, after allowing the fire to burn for 60 seconds, using 680 g of 1-bromo- 1,2,2,2-tetrafluoroethane discharged from a 1230 ml Thorn 39

GD

extinguisher containing 1150 g of l-bromo-1,2,2,2-tetrafli oroethane pressurised to 140 psi with nitrogen.

EXAMPLE 9 A Committee European Normalisation (CEN) 55B fire was started using 55 litres of n-heptane as the fuel. The fire was extinguished in 3.5 seconds, after allowing the fire to burn for 60 seconds, using 950 g of a 30/70 v/v blend of bromodifluoromethane/dibromodifluoromethane discharged from a 1230 ml thorn extinguisher containing 1900 g of the blend pressurised to 130 psi with nitrogen.

a0 4 0000 0ta 0404 0 a0.

39 -6i

Claims

4. The claims defining the invention are as follows: 1. A fire extinguishing composition consisting essentially of: one or more fire extinguishing compounds selected from bromodifluoromethane, l-bromo-l,2,2,2-tetrafluoro- ethane, 1-chloro-l,2,2,2-tetrafluoroethane and 1,l-dichloro-2,2,2-trifluoroethane; optionally a completely halogenated fluorobromo- alkane(s) and/or fluorobromochloroalkane(s); optionally a coadjuvant agent(s) having a boiling point below 0°C; and optionally a gaseous propellant(s). 2. A fire extinguishing composition as claimed in claim 1 wherein the fire extinguishing compound of component (a) is bromodifluoromethane. 3. A fire extinguishing composition as claimed in claim 1 wherein the fire extinguishing compound of component (a) is 1-bromo-1,2,2,2-tetrafluoroethane. 4. A fire extinguishing composition as claimed in any one of the preceding claims which contains a completely halogenated fluorobromoalkane(s) and/or fluorobromochloro- alkane(s).
5. A fire extinguishing composition as claimed in claim j 4 which contains a completely halogentated fluorobror.o- 1 alkane which is dibromodifluoromethane. S 6. A fire extinguishing composition as claimed in any one of the preceding claims which contains a coadjuvant agent(s) having a boiling point below 0 0 C.
7. A fire extinguishing composition as claimed in claim 6 wherein the coadjuvant agent(s) having a boiling point a below 0°C is a haloalkane.
8. A fire extinguishing composition as claimed in claim 7 wherein the haloalkane is chlorodifluoromethane.
9. A fire extinguishing composition as claimed in any one of the preceding claims which contains a gaseous propellant(s). A fire extinguishing device comprising a fire extinguishing composition as claimed in any one of the 39 -7- -8- preceding claims.
11. A method of extinguishing a fire which comprises applying to said fire a fire extinguishing composition consisting essentially of: one or more fire extinguishing compounds selected from bromodifluoromethane, l-bromo-l,2,2,2-tetrafluoro- ethane, l-chloro-1,2,2,2-tetrafluoroethane and 1,l-dichloro-2,2,2- trifluoroethane; optionally a completely halogenated fluorobromo- *1XV11 alkane(s) and/or fluorobromochloroalkane(s); S: optionally a coadjuvant agent(s) having a boiling point below 0°C; and optionally a gaseous propellant(s).
12. A fire fighting composition according to any one of claims 1 to 10 substantially as herein described with reference to any one of the Examples.
13. A method according to claim 11 substantially as Sherein described with reference to any one of the Examples. 4 4 44 4 4 Q I :S4 t i FLP s 444449 4.44 DATED: 21 November 1991 PHILLIPS ORMONDE FITZPATRICK Attorneys for: IMPERIAL CHEMICAL INDUSTRIES PLC bOa-d/S ~b~ 9143S B v