Fire suppression in a sealed system

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Discussion Overview

The discussion revolves around the plausibility of suppressing a fire in a sealed laboratory module within a space station by depressurizing the module to remove oxygen. Participants explore the implications of oxygen removal on fire behavior, particularly in the context of a space environment.

Discussion Character

  • Exploratory
  • Technical explanation
  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • Some participants suggest that removing oxygen from the sealed module would stop the fire, as oxygen is essential for combustion.
  • There is a mention of the Fire Triangle, which includes oxygen as a critical component for fire, indicating that without it, fire cannot sustain.
  • One participant raises the possibility that not all fires may require complete depressurization to extinguish, depending on the materials involved in the fire.
  • Another participant introduces the idea that if the fire is caused by faulty electrical components, the removal of oxygen would likely extinguish it, but questions remain about the potential for re-ignition if heat is not adequately managed.
  • A quiz question is posed regarding road flares burning underwater, which introduces the concept of oxidizers that can sustain combustion without atmospheric oxygen.

Areas of Agreement / Disagreement

Participants generally agree that removing oxygen would likely extinguish a fire, but there is no consensus on whether complete depressurization is necessary or whether other factors, such as heat management, could lead to re-ignition. The discussion remains unresolved regarding the specifics of fire behavior in this context.

Contextual Notes

Participants note the importance of understanding the Fire Triangle and the role of heat in fire behavior, but there are limitations in the discussion regarding the specifics of different fire scenarios and the effects of various materials involved.

Robert House
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Here is the scenario.

An astronaut is conducting experiments inside of a laboratory module within a space station when all of a sudden, a fire breaks out. The astronaut escapes from the laboratory module he was currently using and then proceeds to seal it off using an airlock.

He then deliberately depressurizes the laboratory module of it's oxygen, thereby suppressing the fire inside of it.

Is this plausible? Oxygen is what causes fire to spread so quickly. If there is no oxygen at all within a space capsule, would that stop the fire completely?
 
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Robert House said:
Here is the scenario.

An astronaut is conducting experiments inside of a laboratory module within a space station when all of a sudden, a fire breaks out. The astronaut escapes from the laboratory module he was currently using and then proceeds to seal it off using an airlock.

He then deliberately depressurizes the laboratory module of it's oxygen, thereby suppressing the fire inside of it.

Is this plausible? Oxygen is what causes fire to spread so quickly. If there is no oxygen at all within a space capsule, would that stop the fire completely?
As long as no flammable metals were involved, it should. Are you familiar with the Fire Triangle?

Depending on what was burning, it may not take a full depressurization to put out the fire. It would be nice not to have to waste all that air volume...
 
berkeman said:
As long as no flammable metals were involved, it should. Are you familiar with the Fire Triangle?

Depending on what was burning, it may not take a full depressurization to put out the fire. It would be nice not to have to waste all that air volume...

Let's say in this scenario, the fire was causes by faulty electrical components. I am no familiar with the fire triangle but I will look into that.
 
Robert House said:
the fire was causes by faulty electrical components.
No oxygen, no fire. You'll see that as you read more about the fire triangle.

Quiz Question (for after your reading) -- Why does a road flare burn under water with no oxygen available? :smile:
 
berkeman said:
No oxygen, no fire. You'll see that as you read more about the fire triangle.

Quiz Question (for after your reading) -- Why does a road flare burn under water with no oxygen available? :smile:

Answer: Because the flare contains the perchlorate salt oxidizer
 
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Robert House said:
Is this plausible? Oxygen is what causes fire to spread so quickly. If there is no oxygen at all within a space capsule, would that stop the fire completely?

A close look at the triangle will be a big help. You also are questioning if it will stop completely? In your scenario you are looking at a space capsule of some sort. Heat can be a challenge to dissipate in space. If a fire were to start and the you removed the oxygen it would cease to burn. If there was no follow up to lower the temperature of the fuel it will automatically reignite when oxygen is restored to the space. You are only part way to a complete extinguishment.
 
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