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Concept Development BLUERAD LTD. Presented by: David Atkinson BSc. Chem. Eng. Inventor and Technical Director. Blueproof Concept Development. The majority of vehicles or prototypes typically do not contain active fire protection systems.
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Concept Development BLUERAD LTD Presented by: David Atkinson BSc. Chem. Eng. Inventor and Technical Director
Blueproof Concept Development • The majority of vehicles or prototypes typically do not contain active fire protection systems. • There is nothing in place in most vehicles apart from Fire Extinguishers, for the UK or the majority of the world. • There are however in most vehicles, piped cooling systems and or water supply, which can mitigate against a fire. • Is anti freeze or screen wash a problem? NO • Anti freeze, whose main ingredient is a type of glycol, is used in sprinkler systems in the correct dilution(ref: NFPA National Fire Protection Association Final Report Antifreeze Solutions in Home Fire Sprinkler Systems Prepared by: Code Consultants, Inc. December 2010) • The same holds for screen wash, since is usually also based on glycol.
Blueproof Concept Development • With reference to the Federal Emergency Management Agency (FEMA) of the USA FA-243/April 2003: • Nearly 1 out of 5 fires involves motor vehicles • 1 out of 8 deaths results from motor vehicle fires • Approximately 500 are killed and 1,800 civilians and 1,200 fire fighters are injured each year from motor vehicle fires • And it’s not going down as vehicle sales increase yearly
Blueproof Concept Development • Normally the cooling water system and screen wash system hold fluid solutions that can fight a fire on a vehicle. • The cooling water system is under pressure and the screen wash system has an inbuilt pump. • Radiators and the cooling water system hold a volume of water proportionate to the cooling requirement of the vehicle they are fitted to. An average capacity is 5 litres, considering a General Motors GM Vectra model. • The screen wash system holds a similar amount. In the GM case 5 to 5.5 if an headlight wash is fitted.
Blueproof Concept Development • OK. Consider the impact on the vehicle, particularly the engine compartment or rear end where the fuel tank is normally sited. • We have two sources of supply from either the cooling or the windscreen wash system. • A standing charge available to fight a fire in both. • Is diesel safe? Well unless you put a fire under the fuel tank it does not usually ignite but get a leak on the system and the resulting spray is surprisingly good at igniting, as we have found out in the Offshore Oil and Gas industry where the diesel drivers on fire water pumps and generators are protected by (deluge) active fire protection systems. • We have sufficient supply to use on vehicles Currently we have no systems in place to release or realise the potential of the available fluids to even cover diesel fires.
Blueproof Concept Development • A seldom recognised part of America’s fire problem is motor vehicle fires (Ref. FEMA). It’s the same for the rest of the world. • So, what happens in a vehicle fire? Does it follow the same principles as a home fire? YES Vehicle Home Source: Fire Test F99030A GM Fire Tests Honda Accord NHTSA-1998-3588-201 Source: US Department of Commerce National Institute of Standards and Technology Gaithersburg, MD 20899. Full – Scale House Fire Experiment for InterFIRE VR May 6, 1998
Blueproof Concept Development • Fire test F99030A GM Fire test Honda Accord NHTSA-1998-3588-201 • The probe with 6 thermocouples was positioned along the longitudinal mid-line of the vehicle approximately equidistant from the driver and passenger seat backs • The upper most aspirated thermocouple was approximately 12mm below the lower surface of the headliner • An artificial method of creating an underbody gasoline pool was used. The gasoline was ignited with a propane torch. • The test was stopped when flames were observed on the headlining panel in the test vehicle (after 155s) Note that the front end of the crashed vehicle, holding the fluid for fire protection, is intact. Source: Fire Test F99030A GM Fire Tests Honda Accord NHTSA-1998-3588-201
Blueproof Concept Development • Temperature measurement from the Honda Accord fire test. The fire was not allowed to develop to its full potential. Source: Fire Test F99030A GM Fire Tests Honda Accord NHTSA-1998-3588-201 • The temperature profile is very similar to a fire test on a living room in a house with respect to speed of temperature rise and temperature range.
Blueproof Concept Development • US Department of Commerce National Institute of Standards and Technology Gaithersburg, MD 20899. Full – Scale House Fire Experiment for InterFIRE VR May 6, 1998: • The fuels for the fire test consisted of household furnishings and a liquid accelerant (two cycle engine fuel. 1.0 Lire) • The building was a two storey single family dwelling. • All doors were closed during the test. • Temperatures were measured throughout by strategically placed thermocouples accurate to within plus or minus 7 0C. The temperature range exhibits similar behaviour as for a vehicle fire.
Blueproof Concept Development • The tests demonstrate that for a room we have an expected temperature in the region between 300 0C and 400 0C in 100 seconds from the start of the fire. • That’s about 1.5 minutes measured at a height of around 1 to 1.68 m. • The room temperature rising to around 700 0C at the ceiling in 150 seconds. • For a vehicle the temperature rises to around 800 0C at the roof in 110 seconds. • The vehicle fire is more rapid but comparable with the room fire.
Blueproof Concept Development • Wikipedia suggest that 10 L of water is sufficient to put out a fire. The optimal amount of water is given at 5.4 L or 1.3 Gal for 67.5 m3 space. • As an example, a Vectra holds 5 L of fluid in the radiator, sufficient to put out a fire in a volume of appr. 62.5 m3. • The interior combined passenger and cargo volume in a midsize car is 3.1-3.3 m3,for a large station wagon is approximately 4.5m3. • The fluid in the car radiator is almost twenty times as much as the optimal requirement. • So, how do we get the fluid into or under the vehicle? Wikipedia Source: Hall, Richard. Essentials of Fire Fighting. Fourth Edition. Stillwater, OK: Fire Protection Publications, 1998:
Blueproof Concept Development • A frangible bulb sprinkler head is costly(around 50 euro’s), heavy, and would not maintain its seal on exposure to excessive vibration. • A fusible plug holds dissimilar metals that melt at very high temperature, more costly than a sprinkler head. Usually placed in boilers overhead to allow the softer metal to pour out as it melts. • Not good as we want to save lives not wait until the passengers melt.
Blueproof Concept Development • Plastics have come on in terms of property and suitability. • So could a plastic device be used? • How do we activate the device? • A frangible bulb, the heart of a sprinkler, is basically and by definition a detector. It detects heat expands, and fails open allowing the passage of water in all directions. • A thin plastic wall would behave the same as a frangible bulb however it would target the heat source.
Blueproof Concept Development But do plastics behave like a frangible bulb? NO! It’s better. Plastic goes through phase changes. It reaches its heat deflection temperature then as it goes through the Vicat temperature region, starts to deform and expands towards the heat source prior to failure at the surface. It self targets the heat source. It fails open along the lines of least resistance etched into the surface. So we can have a self targeting device by applying plastic.
Blueproof Concept Development • If we consider a bursting disc then we know by design that the actual thickness of the disc is very thin. Usually around three thousands of an inch for very high pressure applications. • Thermo-plastic materials loose their properties on exposure to heat. This is known as the Heat Deflection Temperature of the material. • So if we form facets around a plastic head with weakened walls in accordance with the design codes, then we have an effective array of bursting discs or areas that will fail open on exposure to fire. • This can be shaped into a form to make a plug and fit on a radiator. The facet will always face the heat source or be targeted directly to the high risk area by fitting to the coolant system pipe work. • As the heat rises on the surface the plastic starts to expand and the available pressure in the system forces it to belly out. It forms its own nozzle facing the fire.
Blueproof Concept Development BlueproofTM device Heat detecting facets
Blueproof Concept Development • Practicality is NO problem! We replace the vent plug on a radiator cap with the BlueproofTM device. This can be done even by the man in the street. For retro fitting just replace the radiator cap. • The BlueproofTM device can still operate as a vent plug but now the radiator cap contains an array of bursting areas and channels for the liquid to escape in the event of a fire. • BlueproofTM device will provide a barrier or form of protection against a vehicle fire.
Blueproof Concept Development • What about the type of fire affecting vehicles? • It is generally either hydrocarbon or electrical. • Electrical, we can isolate on the logic solver. • Hydrocarbon fires in aircrafts are usually extinguished with Aqueous Film Forming Foam (AFFF). • To get the foam into the available fluids we can use a ratio or orifice foam proportioner. • These foam proportioners accurately meter pressurised foam concentrate into the fluid stream. Used in conjunction with a balanced pressure system such as a bladder tank and/or a pumped unit (such as wind screen wash pump). • In operation the fluid induces the foam and creates an effective foam solution.
Blueproof Concept Development • The orifice inducer is based on an earlier patent that was held jointly by Professor Ken Porter of Aston University in Birmingham UK and myself. This is now widely used for inducing drugs on a constant basis to provide pain relief to patients. • The orifice foam proportioner is even simpler than a ratio type and as I invented it, is ‘not prior art’. • So we place a foam inducer between the radiator and the BlueproofTM device. Once the BlueproofTM device fails open on heat detection then the foam is induced and delivered to the fire. • The foam concentrate can be held in a tiny bladder tank and would only be exposed to the radiator fluid on activation.
Blueproof Concept Development • Now, how do we make the exposed areas of the array more responsive and fail open faster? • Catalyst design demonstrates that a rough surface has a greater surface area than a smooth surface. A spoonful of sugar has the same surface area as a tennis court. • Rough the surface of the weak areas. If we etch and form a roughened area the surface will absorb the heat faster and fail across the lines of least resistance. • Colour selection is important as radiation analysis demonstrates that Black is totally absorbing at 1. White totally reflective at 0. So a black rough area will absorb heat much quicker and more efficiently than a shiny white surrounding area which will reflect it. This will hold the integrity of the BlueproofTM device on exposure to a radiant heat source. But as room fires are smoke filled it does not effect the contribution significantly.
Blueproof Concept Development • So moulding is not a problem and the colour is correct! • So, we have a coloured plug head with an array of weakened areas that will fail open on exposure to heat. • What happens during the fire and will the BlueproofTM device that holds the array melt? NO, thanks to the Joule Thompson effect. Two toned plastic plug taken from a domestic radiator.
Blueproof Concept Development • When liquid vaporises at the interface between leaving its source and expanding it obeys the Joule Thompson effect that creates a cooling barrier. Basically an invisible wall that is cool on one side and hot on the other. Similar to ice forming on a valve when it is partially closed. • The Joule Thomson effect actually is the basis of how refrigerators work. On expansion through a small opening cooling occurs on the host. • So, we have a standing charge of liquid between 25 0C and 1350C and on discharge from the system it meets anything between 200 0C and 800 0C degrees. Joule Thompson holds and the effect commences. The BlueproofTM device starts to cool as it releases the liquid.
Blueproof Concept Development • The liquid is driven by the static head and/or available pressure within the system, estimated to be normally between 0.6 and 1 bar. • So we have a spray or jet of liquid leaving the head. • The liquid passing through the head will have a cooling effect on the head and contribute to maintaining its integrity. (Similar to a burner where the host is usually at the same temperature of the gas and at the flame front it can be up to 1200 0C) • At what temperature do we expect the liquid to start to eject?
Blueproof Concept Development • Radiators! • One thing about them is they are optimised to transmit heat. • So in reverse engineering they are optimised to absorb heat. • On exposure to heat from a fire the standing charge in a radiator will reach its boiling point and flash off into the available space, very efficiently, if it can fail open. • On a vehicle it would be the same, the fire would effectively raise the temperature and pressure of the fluid in the cooling system and radiator. • Note. Material is not a major factor as you can boil water in a paper bag.
Blueproof Concept Development • An initial simulation was undertaken with CFAST software by NIST on a single enclosed room by a former colleague who is now working as a deputy Fire Chief with the Italian Fire Authority. • This was a very simple simulation to determine the behavior of a radiator exposed to fire with the BlueproofTM device fitted. • The radiator was simulated with 20 Liters of water and the simulation was ran over 3000 seconds.
Blueproof Concept Development • Simulation results
Blueproof Concept Development • The results displayed that at 80 oC the water would be ejected from the radiator, considering a closed system. However, the plastic heat deflection temperature is around 120oC. • This was calculated from a heat balance considering the heat of vaporisation at the point of release. • So, if we firm up on the temperatures and actual radiator size and efficiency, it adds further support that we have an effective fail open device. • We can conduct similar simulations with vehicle radiators, but the characteristics are very similar to domestic applications, just the enclosed space is different.
Blueproof Concept Development • What happens to the ejected liquid? • The liquid obeys the gas laws. • It expands rapidly and fills the available space. • It effectively cools as it changes state and absorbs the heat from its surroundings. • It displaces the oxygen and deprives the flame front of its fuel source. Asphyxia Strangles the flame. • So the pattern of spray is not so important but getting the fluid into the area is! When the BlueproofTM device fails on the exposed facet it fails open and sprays directly onto the heat source targeting the hottest point! • What if it contains foam?
Blueproof Concept Development • What about the foam? • Fire-fighting foam is used for fire suppression. Its role is to cool the fire and to coat the fuel, preventing its contact with oxygen, resulting in suppression of the combustion. Combined with the vapour properties (as mentioned above) we attack the fire from two directions! • It still obeys the gas laws as the water expands and vapours are released. • Every type of foam has its application: • High-expansion foams are used when an enclosed space must be quickly filled. • Low-expansion foams are used on burning spills: • AFFF is best for spills of jet fuels • FFFP is better for cases where the burning fuel can form deeper pools • AR-AFFF is suitable for burning alcohols and gives the most flexibility. It is used in areas where gasoline's are blended with oxygenates. • So we could apply AR-AFFF
Blueproof Concept Development • We have liquid at raised temperature in the system so we have a faster rate of vaporisation • What does the liquid vapour contribute to? • It creates a liquid vapour sky that prevents roll over and back draught. So the rescuers do not get hit with a wall of flame when they open the hood (or bonnet in the UK) • It makes the particulates fall out as the liquid vapour reacts with them and stops the spread of toxic fumes, making it easer to breath for trapped travellers. • It gives people more time to survive, escape and limits or stops the fire spread. • With the introduction of foam, the threat of ignition to spilt fuel is significantly reduced. This makes the area safer for the Emergency Response Units.
Blueproof Concept Development • What about the water? • Well its from a radiator and contains chemicals. • So we undertake a Health Risk Analysis (HRA) for the water. • We deal with horrendous produced water types in the offshore industry and have to consider the health hazards to protect our employees. AFFF foams have already been subject to HRA. • We have history in dealing with the analysis, hazards and effects. • So we undertake an HRA for each of the radiator contents. • Using ‘Chemwatch’ (the worlds largest chemicals database) we can produce the mitigation sheets as is our normal practice. • How do we apply this? By area entry procedures, onsite risk assessment, Job safety analysis and Health Risk Assessment.
Blueproof Concept Development Temperature Decay How long before it`s safe to enter a space or the fire goes out?
Blueproof Concept Development Well we can see from the graph that the decay occurs almost as fast as the rise. A room will be cooling within 200 to 300 seconds. This is what we expect but we need to firm this up as the concept will activate on the temperature rise, so the affected area should not attain the higher temperature regions. This will shorten the decay time. It will be similar for vehicles as the same principles apply. Expected temperature profile with BlueproofTM device
Blueproof Concept Development What about the road surface? Traffic disruption is normally caused after a vehicle fire when the road surface is badly damaged. This has a major impact on the local community and the invisible costs can be immense! If a road or motorway is closed with diversions and delays to the locality, it has significant cost implications. Emergency services coverage is weakened in its dedicated area, as it is diverted to the incident. Loss to the freight and haulage contractors from damage to the carried contents is also a factor. But by blanketing the road surface and stopping the fire spread to the surrounding vehicles and area would mitigate against this.
Blueproof Concept Development Will it be safer to enter the area? It is never safe to enter an area where fire has occurred!!! We can try and enter the area in the event of saving life only when the emergency response teams are too remote or when circumstances dictate the risk. We leave it to the professionals. In isolated areas, such as the roads in South America or desert routes where there is no chance of the emergency response getting there, we will produce procedures for the vehicle owner’s. These will be made available on the packaging and Website.
Blueproof Concept Development • So we have an item that can be moulded from a relatively cheap material that we can fit on everyone's vehicleor radiator cap and provide protection. • For even better performance, we can place a simple foam inducer between the BlueproofTM device and the fluid source. • Now to finalise design, verify, test, certify, manufacture and get it to the vehicles. • Lets save lives and stop drivers, children and passengers getting burnt alive. Thanks Blueproof TM