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For SpaceNut ...
We have several topics with "fire" in the topic, but they are incidental or accidental
This topic is offered for those forum members who wish to create a legacy of wisdom and actionable advice for the young folks who are going to be designing the ** real ** Large Ships and ** real ** habitats on Mars and elsewhere in the Solar system.
Every last one of these designs is going to have to deal with the risks of chemical combustion.
The first (and best) strategy is to design to prevent unwanted chemical combustion, and to arrange things so that when incidents occur they are easily and quickly extinguished by lightly trained personnel.
An alternative is to plan for fire suppression by Artificial Intelligent agents, who would be on guard 24*7.
We have a model for this in our daily lives on Earth ... the lowly smoke detector is on constant watch to alert any human in the area if there is smoke in the area. The lowly smoke detector can (and I hope ** will ** ) evolve into an every alert fire detection and remediation system for space vessels and for space habitats.
Perhaps there is even a market for such devices on Earth (come to think of it).
(th)
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This was an interesting story
'FDNY Deploys Robot Dogs for Hazardous Search and Rescue'
https://www.firefighternation.com/news/ … nd-rescue/
produced by Boston Dynamics and cost about $75,000 each.
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Successful fire protection depends upon the fuel burning rate in the craft or habitat atmosphere. Oxygen percentage affects that, although it is not the only thing that does. Oxygen partial pressure affects that, although it is not the only thing that does.
If you look at empirically modeling fuel burn rates with an Arrhenius-type chemistry rate equation, the simplest, yet most applicable, model is a one-step, two-component reaction, expressed in terms of oxygen and fuel concentrations. Those are expressed in terms of mass within a unit volume, and each has an exponent in the usual correlated Arrhenius model. The sum of those exponents is usually near 2, and the exponent on the fuel concentration is usually near 1.
That leaves an exponent near 1 for the oxygen concentration. Which makes craft/habitat atmosphere oxygen concentration your variable to be limited. So that the fire burn rate is near what you are familiar with, you want that oxygen concentration to be no more than that of "warm sea level air", meaning 1 atm pressure at about 77 F = 25 C. That value is just about 0.275 kg/cu.m.
Concentration is the mass percent (not volume percent) of oxygen in the atmosphere, multiplied by its density (a function of both pressure and temperature). That's how oxygen percentage and partial pressure feed into this. Not directly, but as the source data.
You can have some higher volume percentages of oxygen, at a lower overall atmospheric pressure, and still meet hypoxia-avoidance requirements without exceeding that oxygen concentration of 0.275 kg/cu.m as a fire danger upper limit. There is a lot of room there. Usually, hypoxia criteria limit what you can do, before you hit the fire danger criterion.
Volume percentages relate to mole fractions (and partial pressures) directly. You must use the component molecular weights with those mole fractions to convert those volume percentages to mass percentages.
Not trivial, but still quite the simple unifying theory.
GW
Last edited by GW Johnson (2022-09-01 10:20:50)
GW Johnson
McGregor, Texas
"There is nothing as expensive as a dead crew, especially one dead from a bad management decision"
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Fire spreads across horizontal surfaces by radiation, which heats the fuel bed ahead of the flame causing it to pyrolyse. The pyrolysis vapours then ignite, spreading the flame. The speed of flame spread depends upon the temperature of the flame, the specific heat of the material burning and the amount of heat needed to pyrolyse material ahead of the flame. Typically, around one third of heat is released by radiation from a small fire. In pure oxygen at 1 bar, flame temperature is typically 30-40% higher than it would be in air.
https://www.thoughtco.com/flame-tempera … ble-607307
propane flame temperature: 2,820 °C (oxygen), 1,980 °C (air)
Propane flame temperature in Kelvin, is 1.37x higher in oxygen. Radiatied heat flux increases with the fourth power of temperature. In an O2 atmosphere at 1 bar, fire radiant heat flux would be 3.5x greater than in air at 1 bar. However, is a 300mbar pure O2 atmosphere, combustion rate and heat release would be only one third of a pure O2 1 bar atmosphere. So realistically, fire growth rate might be 20-30% higher.
I would suggest watermist in a low gee environments. Brownian motiin with keep the drops airborne, allow them to be drawn into the flame.
Last edited by Calliban (2022-09-01 15:57:43)
"Plan and prepare for every possibility, and you will never act. It is nobler to have courage as we stumble into half the things we fear than to analyse every possible obstacle and begin nothing. Great things are achieved by embracing great dangers."
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For GW Johnson re #3 - thank you for details of partial pressures related to fire safety
For Calliban .... your suggestion of a water mist dispenser for an enclosed space vessel or Mars habitat seems well worth testing.
On Earth, a crude version of your idea is the overhead water dispensing systems that are released when a temperature sensitive material "melts" due to hot gases.
Google came up with numerous citations that relate to fire safety in ships (commercial freight or passenger) ...
Here is one that seems (to my eye at least) to cover the basics ...
https://www.marineinsight.com/marine-sa … ard-ships/
The key idea that jumped out at me from that article is the need for frequent and intense fire inspections.
A ship far from Earth would seem (to me at least) a good place for fire discipline.
(th)
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https://www.marineinsight.com/marine-sa … -on-ships/
It took quite a bit of laboratory analysis to discover the reason for the fire discussed in this article.
The bin was being filled according to standard practices at the time.
However, unbeknownst to the crew (or anyone, apparently) there is a kind of bacteria that gives off heat under the right conditions. Since the bin contained oily rags as well as food waste, the conditions were optimum to create ignition.
It is a good practice to have a garbage management plan and to follow it strictly on board every ship. A practice of segregating garbage, for example oily rags in a separate bin, food waste, metal scraps, ash, batteries, etc. assigned to different bins and colour coded is mandatory these days in all ships. It is also a good idea to clear of all the bins before unmanning the engine room.
We have three ship designers (of varying skill levels) working in the forum at the moment. Fire protection needs to be included in overall system design.
(th)
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USCG Urges USCG to Remove Subchapter K Exemptions for Fire Safety
https://www.marinelink.com/news/uscg-ur … r-k-508992
The sinking of MV Conception
Four years after dive boat fire killed 34 people near Channel islands, captain’s trial begins
https://www.dailynews.com/2023/10/24/fo … al-begins/
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Robots could make great fire fighters, they also can be designed and programmed to meet the needs of colonists without any political or historical baggage weighing them down. I'm not sure how big economics and politics on Mars will be, perhaps it will be economic networks of smaller systems like you see on the Marshall Islands, if an outside economic force wants to muscle-in on territory I'm not sure Mars would stop them. Mars is not like colonization of the new world, there will be no Native Americans, no Empires invading a collapsing Qing Dynasty, no Native American 'First Peoples' population to exploit, so perhaps its colonization should be compared to the attempts to build bases on the continent of Antarctica. Just because a military force does not exist on Mars that does not mean that people from military from places on Earth might not contribute some kind of 'peace time' role, the Airforce and Navy of various Nation and Kingdoms on Earth are able to deploy to various State and Territory the first Mars Firefighter response teams might be 'Private Sector' but they might also link to Military experience and Governments. We have started to deal with many disasters on Earth, fires put out after a landslide, electrical fire fighting techniques during a flood, how to put out and save people in poor weather conditions when an aircraft cash lands. One force we are not able to stop is 'War' while we learn to deal with other disaster forces from nature.
Fires create massive death toll, they are especially dangerous for a ship at sea on Earth or an aircraft flying can see loss of all with everyone killed. The old Socialist Democratic Republic of Afghanistan linking to the USSR seen death toll estimated at 2,700 to 3,000 people, including 700 Soviet soldiers, Cocoanut Grove fire was a huge nightclub fire which took place in Boston, the Kingdoms and countries of Austria-Hungary region had huge death tolls from miner fires, Dabwali fire accident seen hundreds of Hindu kids die at a Indian private school there are also cultural clashes with Meos islamic jihadi muslims and Sikhs in the region, a religious event seen a Jesuit church burning located in downtown Santiago they say between 2,000 and 3,000 people died. When exit were locked becase of theft coming through a backdoor Ycuá Bolaños supermarket fire killed even more than it should ahve hundereds dead and hundreds more injured, fires might also cause panic and see hundreds or thousands killed by crowd panic and stampede events like what happened in the Middle East, a deliberate terrorist attack the Iranian Cinema Rex fire was first blamed on 'Marxists' but the public outrage eventually gets Iranian islamic jihadi militants into power.
I do not think weapons should be sent to Mars, sometimes we have examples of trying a peaceful society in our scifi works. In the fictional world of Star Trek there is an idea of Prime Directive, its most important rule "Starfleet General Order 1" the idea of the "non-interference directive" is a guiding principle of StarTrek says selling laser guns and space ships to a primitive war like people is banned, a rule that prohibits its members from interfering with the natural development of alien civilizations. Gene Roddenberry the scifi writer is no longer alive, he might have been disillusioned and disgusted with today's US Democrats but he might be described as a Traditional Libertarian Democrat of his time, the prime directive an example of a political comment on a superpower interfering in the natural development of other smaller society
Any type of War on Mars I feel would be a complete waste of time, life and wasting energy. However a post by Kbd512 and other posts reminds me that wars have happened and can happen again, even in a region on planet Earth built up over generations with great history, with wealths of culture to trade to the West and East, access to minerals to Lakes and Seas, trade route to the northwest, the Caspian Sea and to the north, an old Silk road crossing West to the East, an older Middle East and history of building and tourism sites of Mesopotamia and the Gulf of Oman and the Persian Gulf to the south, island countries of Europe's South East and Mediterranean civilization, the Pyramids of Egypt not far away this region rich in resource has seen massive conflict. If people in a certain part of Mars act with an element of uncivilized nature fight among themselves the criminality of savage local conflict or barbarism, I feel Earth should mostly stay out of it. There might be some kind of Control of Arms where any type of possible export that can be made into weapons are restricted, a United Nations type system or United Moon and Planets of Sol might come to agreement. Earth might have its own policy it might maintain a strict policy of neutrality yet still prepared for battle against a local threat for example 'Space Pirates' for lack of a better description. A fight in a future not be nations but company and corporation. One problem on Earth by using a United Nations peace keeper force is it can soon be overwhelmed by a stronger terrorist militia, its armored cars, its helicopters, its tanks and Armored machine gun tank-car seem to be leftover donations of 2 generations older equipment from the 1960s, a new terrorist force has the ability to over power UN forces, there are also scandals from the UN such as 'forced prostitution'. Some engineer and businessman with bad intention for profits are becoming sales people in weapons of death, Kalashnikov has killed more people than the Atomic bomb by way of sales of 'defense manufacturing'. If something is seen by observation a ground camera or satellite observes a 'Cuban Missile Crisis' on Mars then maybe like Cuba it gets frozen in time by way of commercial, economic, and financial embargo maybe a United Planets setting up a Space Force block and restriction. I feel Musk is neutral in all this, he has no time for selling weapons he is a pacifist that makes cars, he is involved in the tunnel transport the Boring Company; co-founder of Neuralink, he is involved in social media buying twitter and changing its name to 'X' and AI system, he makes rockets.
The robot AI machine would be there on Mars in time of peace and help fight fires,the Artificial Intelligent agents would be very useful in suppressing fires however I think I would still want a human Fireman as back up and there might be an issue where the AI computer has a 'false reading' wastes resources and deploys by mistake. What do I mean by this?
In Antarctica they have such systems and maybe it can trigger by an aurora flash or far off lightning or some tourist arriving and doing 'Flash Photography' the computer system triggers an alarm, the fire is chemically suppressed and you only have seconds to run into some bunker with water and oxygen as stuff gets sprayed everywhere inside the South Pole Base.
Humans and the Nations of Earth might be mature enough to think Mars should not have war or guns and come to some form of agreement to keep Mars event free like the Space Station and the nature reserve and scientific research at the South Pole. The reason I mention peace-time Airforce and Navy experience is because sometimes military peace duties include quality and safety regulations for ship structure, they might deal with fighting off natural disasters, rescue and protection of civilians, the Army knows things about machinery, control systems, electrical systems, fire safety, environmental hazards and more, it would be unwise to dismiss their expertise and years of experiences in remote difficult locations. Working with people in military and other occupations can give benefit from past experience, a Police or Military or Doctor or Military might provide advice on investment in improved technologies. The military is good at breaking, attacking, blowing things up but they do have other achievements and discipline, one thing a military is good at is drills, they will train and practice scenarios, they will go through simulation and demonstrate their ability to extinguish a fire using some new technique or new rescue method in a landmark training activity.
On Mars might not follow the cooperative example, the humans might break into separate groups or religion type factions. Teams and political tribe of people going against each other seems to be a natural part of human history, in sports and business, the long-time rivalry between soft drink producers, in any competitive environment, once you add political groups, different and religions into the mix tensions might increase. Although the ISS and South Pole are examples where humans of different cultures work together peacefully for some reason perhaps not having a treaty or the 'Wrong Treaty' the people on Mars might not work together. I won't pretend to know as much as women do when picking color and fashion choice for their clothes but on Mars the different factions or group might simply separate with their own t-shirts and flag colors.
Let us speculate that regions or of Mars do have different peoples, maybe different groups, political systems and a clash of religions or flags.
The Dark Red-ish-Orange faction with their own flags and symbols,
there might be a sandy Gold-Amber designed flag with its own logo,
Aero-blueish-whiteish-Alice blue for people who take minerals and water at the Pole
there could be a group with a Battery Cadmium Acid Orange-Yellow and their symbols,
Martians who manufacture and make unions might be a bright 'Golden Flame' political group from the town that makes engines,
on Mars there might be a Farmer separatist group with Brown soil symbols and Green plant colors in their Flags
or maybe a Biosphere color based on Army green, Corn-Maize or Mushrooms or spices or teas
one group might link to media or entertainment, soft drink makers, colors of instruments, virtual beaches blue sea or Tobacco or Wines
a Faction might have many metal colors, nickel, aluminum, calcium and Silver
there might be a historical UN linked group Navy Submarine color of Space cadets
On group might simply use Black and White and Grays in the flag
there could be a flag of a bright Orange-ish Red Faction and their own sports team and religion customs.
If the 'War Merchants' arrive on Mars then different groups of Martians might get supplied with these weapons of death, they might have their fighting vehicles, their own high tech missiles, they might have types of Car with armor or Tanks, a type of howitzer for use in space, types of military Mars Helicopters and Drones, types of Anti-tank missile, types of rifles, grenade launchers people will continue selling these guns and bombs for profits. It could get too late to cut and control supplies, the groups on Mars might start to reverse engineer and 3-d print their own home-made war designs. An example on Earth, there were a lot of US Weapons Left Behind in Afghanistan (Taliban controlled) which might now go to Iran and be reverse engineered. Iran has F-14 Tomcats sold to Iranians sold when the last Shah (King) of the Imperial State of Iran existed, before he flees the country and the take over of islamics during the Iran hostage crisis during Carter's Admin, Reagan also starts drug running and gun running in Irangate. They got Soviet Chinese style missile, they had French technology, the Swedish were selling to anyone , the global idiots of Swedistan manufactured these terrorist-boats the company Boghammar Marin the Iranians might have first got other weapons of war indirectly from from Czechoslovak-Soviets, the boats are used by Nigerian militants, Tamil-Tigers suicide bombers, and Somali pirates. The Iranian Corvette and Iran Frigates were originally built for the US Navy, they have French designed ships or Swift vessels also and British designed military hovercraft sold to Iran, the old California tank track armored personnel carrier used in the Vietnam war and used by Israel, Francoist Spain dictatorship and Junta of Portugal also found itself sold to the Iranians. Just like the Gulf War or Operation Desert Shield and Operation Desert Storm, the West fought many of its own self-made weaponry and also foreign Soviet weapons. In Iran conflict in the fight in the Persian Gulf a civilian supply ship Willie Tide found itself under attack. There was a Russian Soviet destroyer that popped up in the middle of Battle claiming to watch the movie of it all and when asked what their intentions was, the Soviet captain claims he was there to take pictures for history. The Iranians also had US made F-4s the McDonnell Douglas Phantom still used by Spain, Turkey, Israel, Australia, Egypt and Japan until 2021. When Iran went kamikaze a political suicide bomber attacking others then shooting at supply ships and hitting the Oil Market outside of Opec the US Navy moved in to protect Kuwaiti shipping after several attacks on tankers operating in the region. The short fight in the 1980s was a complete mismatch, The Iranians also have their own UAVs some with technology made in the United States of America, a MQM-107 Target drone, in 2012, it was reported that North Korea had acquired several MQM-107D aircraft second-hand from a Middle Eastern country. The USA Navy vs Iran Navy was a fight where Iran was over powered, its Navy mostly destroyed. However Iran is building up its military again and Putin is buying drones from them to use in the invasion of Ukraine War. The Biden Admin has also given Iran lots of money but also accused them of being involved in the Gaza Israel-Hamas War, the Saudi Sunni islamic type have their own ambition vs the Shiite islamic type and there might be deepening struggle between U.S., Iran for Mideast influence. Iran Navy recently seized a Marshall Islands flagged suezmax tanker, there were once attempt to make islands British or German protectorates, Japanese invaded the islands with occupation force in WW2, the islands have a relationship with Australia and the USA, in the ColdWar islands became Atomic Bomb test sites Islanders being forcibly relocated, in recent years all five of the SpaceX Falcon 1 rocket flights were carried out on Omelek Island within the Kwajalein Atoll. I think whatever political and religious problems are on Earth should be left behind on Earth. The experience of a Airforce putting out fires or Navy putting out fires is useful, the experience of a group like 'Red Cross' in rescue and ideas for resources is helpful, if an event were to happen on Mars then a colony might require new radical techniques such as aerial firefighting.
Here are pics of the giant hole in the Samuel B. Roberts and somehow the ship managed to limp away,
https://www.alamy.com/stock-photo-a-vie … 79295.html
https://nara.getarchive.net/media/a-pho … ate-0a4271
the crew managed to save the burning ship the ship severely damaged by that event in the 1980s returns to duty, the ship was fixed, the hole patched up and served until decommissioned in 2015.
Last edited by Mars_B4_Moon (2023-10-24 17:50:43)
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Imagine a flying dragon that doesn’t spout fire, but instead extinguishes it with blasts of water. Thanks to a team of Japanese researchers, this new kind of beast may soon be recruited to firefighter teams around the world, to help put out fires that are too dangerous for their human teammates to approach.
https://www.eurekalert.org/news-releases/1029353
Scientists develop ‘flying dragon’ robot to fight fires from a distance
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