In today's installment we take a look at the Elide Fire Ball and then firefighting in general.
What is in an extinguisher ball?
Patent US6796382B2 that was given to Woradech Kaimart expired in 2021, and describes an explosive fire extinguishing device "...wherein the force of detonation of the device is minimalized ... no part of the device having sufficient mass or density to typically constitute a safety hazard as flying debris...The present invention is composed of a lightweight casing of rigid plastic .... Within the internal cavity of the device, a low explosive yield detonator is located ... and is actuated by fuse cord(s) extending from the detonator...to a mounting at or near the exterior surface. The interior volume of the hollow casing is chargeable, through variations in internal configuration, with a variety of fire-retardant chemical agents, including dry powders, two-part reactants, liquid components or others".
This isn't actually too dissimilar to automatic chemical fire extinguishers except that it does use explosive detonation rather than pressure, and thus the periodic pressure checkup of standard fire extinguishers is unnecessary, and the activation mechanism is different. And note you can actually hold one of these while it explodes, since there's nothing massive enough in the explosion to be a shrapnel hazard - like an explosion of flour or dust, you'll get covered in white powder but otherwise be unharmed.
Fire Fight
Elide Fire Ball Pro, the Thai manufacturer and vendor of Kaimart's "Elide Fire Ball", sued Alibaba Advertising and Jack Ma, Mr. Ali Baba himself.
Elide Fire accused Alibaba of promoting the sale of the much cheaper "AFO" fire-extinguishing ball, which it says is a counterfeit good, through its website to buyers around the world through its e-commerce system.
Elide claimed the AFO cannot actually extinguish a fire, hurting the reputation of the patented product, with distributors losing confidence in Elide by association and cancelling orders.
The result of the firefight is unclear , and thus the parties probably settled out of court - if you check AliExpress, you'll still find AFO and no Elide.
The Samsung fire vase (above) is a somewhat similar product packaged like a flower vase - but sufficiently different from the fire ball that they apparently avoided any patent infringement accusations.
Firefighting In General
And now for some stats, without which no blog post would be complete. In the US, in 2019 there were 1.3M recorded fires which caused 3700 deaths, 17000 injuries and $15 Billion in damage. [US Fire Administration]. Cooking, heating, unintentional causes, electrical sources, and arson were the top causes in residential fires, together accounting for 80% of the cases.
So how does fire extinguishing actually work? If you've ever tried to light a campfire with tinder and matches, you'll understand that getting a fire started can be a delicate process requiring three ingredients - oxygen, fuel, and heat.
As cooking is the leading cause of fire (in nonresidential settings as well), plenty of systems have been invented to deal with the problematic oil-based fires that can occur (these being resistant to water) . Patent Count - 136K patents under 'cooking fire suppression'.
Given that water won't put out all fires its natural that different types of extinguishers have been developed for different fires. Class A works on dry fuels, B is for flammable liquids and C is designed for electrical fires. Materials that have been found to be good for fighting various fires are listed below.
Pressurized Water - Combustibles (Class A)
Pressurized water extinguishers (eg the fireman's hose or a pressurized water can) are only fit to battle "A" fires. The average pressurized water extinguisher discharges ten liters of water in about a minute, with a range of 10-15m. This method smothers fires by cooling the burning material below the ignition point; as water has an extremely high specific heat, it takes a lot of energy from the flame to heat/boil the water, and enough water will 'win' the competition between energy produced by combustion and energy absorbed by heating water.
Carbon Dioxide - Flammable Liquids (Class B,C)
Carbon Dioxide extinguishers fight the fires that pressurized water extinguishers cannot. They're optimally deployed against "B" and "C" fires and significantly vary in their sizes and discharge time. They can be heavier (up to one hundred lbs.) and have a discharge time between eight and thirty seconds. The carbon dioxide doesn't lower the temperature of the fire like the pressurized water extinguisher, it displaces the oxygen fueling the fire instead. Note that as the temperature of the fire drops, the effectiveness of carbon dioxide extinguishers decrease. CO2 extinguishers also require a less rigorous clean up than other extinguishers, making them a more attractive option when dealing with expensive equipment.
Powdered graphite, granular sodium chloride, copper powder -Flammable Metals (Class D)
Flammable metals include aluminium, magnesium, titanium, sodium, potassium, uranium, lithium, plutonium and calcium. Class D extinguishers have been developed to deal with such, and can use sodium chloride, somewhat surprisingly - if your sodium metal has spontaneously combusted (see video below), just add salt...which is half sodium!
If you try to put out such a fire with water or carbon dioxide you will have a bad time; see video below:
Class A,B,C. Multipurpose Dry Chemical
The multipurpose dry chemical extinguisher is the workhorse of fire protection. Unlike the CO2 extinguisher, it has a pressure gauge to allow you to check the capacity visually rather than by weight. The range for these is generally between 2m-6m and it works by physically separating the fuel from oxygen in the air.
Class K. Wet Chemical
As found in McDonald's kitchens worldwide. Even though class "K" fires are a subset of class "B" fires, they must be treated with extra care and thus warrant a dedicated extinguisher type. The wet chemical extinguisher can discharge for up to forty seconds at a maximum effective range of ten to twenty feet. It utilizes a foam-forming agent that prevents persistent kitchen fires from reigniting.
Oil Wells - Snuffing
Red Adair pioneered a 'snuffing' technique whereby a violent, water-resistant oil-well fire is put out by use of explosives that use up all the available oxygen in the surroundings, snuffing out the fire and allowing the well to be shut subsequently.
The Soviets took a somewhat more radical approach. 'What is more radical than putting out a fire with explosives' you may ask? Putting it out with a nuclear detonation...
Aircraft - Foam
If you thought this section was going to be about airplanes dropping foam on fires, wait a few sections. Housing aircraft in hangars that often have some amount of jet fuel lying about poses some unique challenges.
Planes in hangars are often in close to both fuel sources and ignition sources so the potential for fuel spill fires is very real. To deal with this many hangars have foam fire suppression systems, which can automatically and effectively extinguish a fire by smothering it, although frequent false alarms have caused considerable damage.
Server Rooms - Halon Gas
In a context where you want to do as little damage to equipment as possible, a heavy gas like halon can be used to displace all the oxygen-containing air in a small enough / airtight-enough room, snuffing out the fire like the oil-well explosive system above, but without the inconvenience of an explosion that wipes out your million dollar server stacks. Just make sure any useful employees evacuate, as they need oxygen too.
Forest Fires
Global warming apparently being a thing, fighting forest fires with aircraft is taking off...heating up...catching on...and all the rage. Some current tech:
Single Engine Airtankers can deliver ~800 gallons of fire retardant. Aircraft types: Air Tractor AT-802.
Large Airtankers - can deliver 2,000 - 4,000 gallons of fire retardant. Aircraft types: P2V, HC-130H, BAe-146, MD-87, C-130Q, RJ85, C-130 H & J equipped with Modular Airborne Fire Fighting Systems (MAFFS).
Very Large Airtankers (VLATs) are capable of delivering over 8,000 gallons of fire retardant. Aircraft Type: DC-10.
Water Scoopers (see video below) are amphibious aircraft that skim the surface of a water body and scoop water into an onboard tank and then drop it on a fire. Aircraft types: Bombardier CL-415 and Air Tractor Fire Boss.
Nuclear Reactors
That leaves a few special cases, such as nuclear reactor core fires, which should generally be dealt with by getting as far away as possible, and second of all by the Russian method (which involved dumping neutron absorbers e.g. boron onto the reactor core, at the expense of several helicopter pilots)
Some extinguisher Types
Hanging Type Extinguishers
These automatic extinguishers are mounted on ceiling or wall, and spray the area with a fire-retardant powder (generally an A/B/C mix).
But these days, extinguisher balls are a lot more popular and more widely available. You can still find this type of hanging-type extinguishers in the UK, but in the US they’ve pretty much disappeared, probably caused by a combination of the extinguisher balls being cheaper, lighter, and their lack of a need to be mounted to a wall or ceiling.
Aerosol Extinguishers
Aerosol extinguishers are like little fire extinguishers in a spray can, with ~20 seconds of spraying capacity. They’re convenient and kids/elderly can use them without trouble as most people have used spray cans - but they do spray a relatively small area compared to extinguisher balls or handheld extinguishers. Number of patents under 'aerosol fire extinguisher': 130K.
Handheld Extinguishers
This is the type we all think of when you hear the term fire extinguisher. Most use ABC dry chemical powder, and they have more fire-stopping power than the fireball/vase/aerosol, but less than a sprinkler system, foam, halon, or the Russian favorite, small nuclear device (see above).
You can also get handheld CO2 extinguishers (class B,C) that don’t leave any residue or chemicals at all.
Number of patents under 'hand held fire extinguisher': 135K.
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