Abstract: A fire and explosion suppression system comprises a source (5) of high pressure water which is fed to a misting nozzle (13) at one input of a mixing unit (6), and a source (14) of high pressure inert gas, such as nitrogen, which is fed along a pipe (20) to another input of the mixing unit (6). Inside the mixing unit (6), water mist, in the form of an atomized mist of very small droplet size is mixed with the pressurized gas and exits the mixing unit (6) at high pressure and high velocity along a pipe (22) and is thence discharged through spreaders (26, 28). The source (5) of the water is pressurized by a feed (30) from the source of pressurized inert gas. The mass flow rate of the water will therefore reduce as the pressure of the gas decays. This tends to maintain the ratio of the mass flow rate of the water to the mass flow rate of the gas constant. This is found to produce and maintain an advantageous distribution of droplet size in the discharged unit.

Abstract: In a first aspect a fire fighting foaming composition contains a partially acetylated polyvinyl alcohol. In a second aspect the fire fighting foaming composition contains chitosan together with a surfactant such as a protein derived surfactant or a hydrocarbon surfactant which is either amphoteric or non-ionic. The compositions can form effective fire fighting foams in the absence of fluorinated surfactants and other fluorinated compounds.

Abstract: A fire extinguishing or explosion suppression device comprises a chamber and a nozzle. The nozzle defines a discharge pathway from the chamber. The chamber has an inlet for pressure-driven introduction of a liquid into the chamber. The chamber is shaped so that a gas contained in the chamber before the introduction of the liquid is entrained into the liquid during the pressure driven introduction of the liquid such that a mixture of the liquid and the gas is discharged through the nozzle to create a mist for extinguishing a fire or suppression of an explosion. After the gas has been discharged from the chamber, the nozzle produces a spray having a core of larger liquid droplets with the core being surrounded by smaller liquid droplets.

Abstract: A temperature switch comprises a material (14) which melts and concomitantly undergoes a change in an electrical characteristic at a predetermined temperature. The temperature switch also includes at least two electrical contacts (10, 12) for detecting the change in the electrical characteristic. The material (14) comprises an organic cation and an anion and is preferably an ionic liquid.

Abstract: A water and inert gas fire suppression system (10), and method for extinguishing a fire in a protected space are provided with a simple and inexpensive freeze protection mechanism. To prevent the water, or other liquid fire extinguishing agent, entrained in the inert gas flow from freezing during transport through the inert gas distribution network (15, 15a, 15b, 17, 19) a secondary liquid is introduced into the inert gas flow and then removed from the inert gas flow upstream of the discharge of the two-phase water and inert gas flow into the space being protected. The inert gas is heated by means of the thermal inertia (TI) of the secondary liquid, which may be excess amount of water or an amount of another liquid having a thermal inertia (TI) at least equal to that of water.

Abstract: Apparatus for rapid discharge of one or more fire extinguishing agent(s). The apparatus includes a sealed container forming an interior volume in communication with a rapidly opening valve assembly. The interior volume contains fire extinguishing agent(s), super-pressurised by a gas such as nitrogen. A portion of the nitrogen is dissolved into the fire extinguishing agent(s). When an incident is detected which requires the discharge of the fire extinguishing agent(s) the valve is opened. Opening the valve causes rapid dissolution of the nitrogen from the fire extinguishing agent(s), forming a two-phase mixture (like a foam or mousse) which substantially fills the volume and causing the discharge of fire extinguishing agent(s) from the valve assembly.

Abstract: A fire detection system for monitoring a volume containing fluid, typically air, for the presence of smoke particles is disclosed. A conduit for receiving the fluid, and any smoke particles therein, and directing the fluid to a smoke detector has a plurality of inlets formed therein. A respective temperature sensor is associated with each of the inlets which generate a signal indicative of a change in temperature in the region of the inlet. In the embodiments, the temperature sensor comprises one or more fiber Bragg gratings. The fiber Bragg gratings preferably have different grating periods. The reflected light from each fiber Bragg grating is returned back down the fiber optic cable and redirected via a 2×1 coupler to a wavelength detection system and a personal computer.

Abstract: A temperature switch comprises a material (14) which melts and concomitantly undergoes a change in an electrical characteristic at a predetermined temperature. The temperature switch also includes at least two electrical contacts (10, 12) for detecting the change in the electrical characteristic. The material (14) comprises an organic cation and an anion and is preferably an ionic liquid.

Abstract: A temperature switch comprises a material (14) which melts and concomitantly undergoes a change in an electrical characteristic at a predetermined temperature. The temperature switch also includes at least two electrical contacts (10, 12) for detecting the change in the electrical characteristic. The material (14) comprises an organic cation and an anion and is preferably an ionic liquid.

Abstract: A fire extinguishing or explosion suppression device comprises a chamber and a nozzle. The nozzle defines a discharge pathway from the chamber. The chamber has an inlet for pressure-driven introduction of a liquid into the chamber. The chamber is shaped so that a gas contained in the chamber before the introduction of the liquid is entrained into the liquid during the pressure driven introduction of the liquid such that a mixture of the liquid and the gas is discharged through the nozzle to create a mist for extinguishing a fire or suppression of an explosion. After the gas has been discharged from the chamber, the nozzle produces a spray having a core of larger liquid droplets with the core being surrounded by smaller liquid droplets.

Abstract: A system for discharging inert gas for extinguishing or suppressing a fire is disclosed. A fluid discharge control arrangement is positioned in a fluid flow path between a pressurised gas supply 10A,10B,10C and the target fire suppression zone 20. The fluid discharge control arrangement reduces the pressure in the fluid flow path downstream thereof. This may allow the downstream pipework to be selected to withstand a lower pressure than in a conventional system in which the fluid discharge control device was not provided, thereby reducing costs. The fluid discharge control device may comprise a first valve 30 and first restrictor 26 in the first flow path 22 and a second valve 32 and a second restrictor 28 provided in the second flow path 24. Fluid from the containers 10A,10B,10C flows initially through flow path 24 and restrictor 26. Subsequently flow path 22 may be closed by optional valve 30, and flow path 24 is opened by valve 32. Fluid flow then passes through restrictor 28.

Abstract: A temperature switch comprises a material (14) which melts and concomitantly undergoes a change in an electrical characteristic at a predetermined temperature. The temperature switch also includes at least two electrical contacts (10, 12) for detecting the change in the electrical characteristic. The material (14) comprises an organic cation and an anion and is preferably an ionic liquid.

Abstract: A fire extinguishing or explosion suppression device comprises a chamber and a nozzle. The nozzle defines a discharge pathway from the chamber. The chamber has an inlet for pressure-driven introduction of a liquid into the chamber. The chamber is shaped so that a gas contained in the chamber before the introduction of the liquid is entrained into the liquid during the pressure driven introduction of the liquid such that a mixture of the liquid and the gas is discharged through the nozzle to create a mist for extinguishing a fire or suppression of an explosion. After the gas has been discharged from the chamber, the nozzle produces a spray having a core of larger liquid droplets with the core being surrounded by smaller liquid droplets.

Abstract: In a first aspect a fire fighting foaming composition contains a partially acetylated polyvinyl alcohol. In a second aspect the fire fighting foaming composition contains chitosan together with a surfactant such as a protein derived surfactant or a hydrocarbon surfactant which is either amphoteric or non-ionic. The compositions can form effective fire fighting foams in the absence of fluorinated surfactants and other fluorinated compounds.

Abstract: In use of a UV gas discharge tube (such as used in flame monitoring apparatus), an electric field is periodically applied in the tube, each application of the field being followed by an ‘off’ period in which the field is removed. During this process, the mean value of the statistical lag Ts is measured over a predetermined time duration (the statistical lag is the time lag after each application of the electric field to the tube before conduction (if any) takes place). If the statistical lag lies within region I, the flame is judged to be present. If the statistical lag lies in region II, the flame is judged to be off (and a warning may be signalled). If the statistical lag lies in region III, a fault in the tube is signalled. This may be a “field emission” fault whereby free electrons are generated by the applied electric field, without the presence of UV radiation or it may be a “multiple counting” fault.

Abstract: A fire detection system for monitoring a volume containing fluid, typically air, for the presence of smoke particles is disclosed. A conduit for receiving the fluid, and any smoke particles therein, and directing the fluid to a smoke detector has a plurality of inlets formed therein. A respective temperature sensor is associated with each of the inlets which generate a signal indicative of a change in temperature in the region of the inlet. In the embodiments, the temperature sensor comprises one or more fibre Bragg gratings. The fibre Bragg gratings preferably have different grating periods. The reflected light from each fibre Bragg grating is returned back down the fibre optic cable and redirected via a 2×1 coupler to a wavelength detection system and a personal computer.

Abstract: A smoke detector (1) has a spherical chamber (2) including a plurality of holes (15,17) for allowing smoke and other particles to enter the chamber. The majority of the internal surface (3) of the chamber (2) is covered with a high reflectivity Lambertian surface, that is a material that scatters incident light equally in all directions and at all wavelengths. The remaining portion of the internal surface (3) is coated with a light absorbing material (13) such as a matt black coating. A scatter sensor (9) is directed towards the absorbing coating (3), and an integrating detector (5) is configured to detect radiation directly from the entire Lambertian surface. A first LED (19) emits blue light into the chamber (2), and a second LED (21) emits infrared light into the chamber. Processing means (23, 25 and 27) are provided to analyse the signals from the detectors (5,9), including means for discriminating between signals from the sensors indicative of different frequencies of received radiation.

Abstract: A method and device for sensing spatial variations and/or temperature variations in the locality of a fiber optic cable 1 is disclosed, wherein a broadband light source 47 is used to shine incident light onto a series of fiber Bragg gratings contained within zones A, B and C. Each zone contains a plurality of fiber Bragg gratings, the plurality of fiber Bragg gratings in any one zone having a substantially identical grating period, and the fiber Bragg gratings in the respective zones having different grating periods. The reflected light from each fiber Bragg grating is returned back down the fiber optic cable 1 and redirected via a 2×1 coupler 51 to a wavelength detection system 53 and a personal computer 63. The combination of wavelength detection system 53 and personal computer 63 allow analysis of the reflected light patterns, as well as providing a user interface which enables detection of the occurrence of a spatial and/or a temperature variation.

Abstract: A temperature switch comprises a material (14) which melts and concomitantly undergoes a change in an electrical characteristic at a predetermined temperature. The temperature switch also includes at least two electrical contacts (10, 12) for detecting the change in the electrical characteristic. The material (14) comprises an organic cation and an anion and is preferably an ionic liquid.

Abstract: In order to allow a smoke detector unit to be utilized in, for example, a domestic kitchen environment, appliances whose operation is commonly associated with the generation of non-hazardous smoke or aerosols are connected to a conventional mains supply socket via a current monitoring unit. The current monitoring units include a radio transceiver, which transmits the operational status of the appliances to a corresponding transceiver of the smoke detector unit 1. If the signals transmitted by the current monitoring units indicate that the appliances and are off, the smoke detector unit generates a warning signal when the smoke density exceeds a lower threshold. If one of the appliances and is detected to be on, the smoke detector unit generates a warning signal only when a second, higher threshold of smoke density is exceeded. Optionally, when the higher smoke density threshold is exceeded; the smoke detector unit transmits the signal to the current monitoring unit to power off the appliances.