During his stay on the International Space Station (ISS), astronaut Tim Peake described the fire safety procedures and technology that kept the crew safe from disaster. As it turns out, most of the fire safety basics are the same in space as they are down here on earth, although there are a few key differences.
Some aspects of the environment inside the ISS make fire prevention easier. But those very same elements also increase the risk significantly, so astronauts have to know their fire safety procedures inside out and back to front.
Here’s a brief overview of what it takes to manage fire safety well outside our planet’s atmosphere.
Fire Retardant Materials Are Essential
All materials used on the station are tested for flammability in a special chamber that mimics the conditions found in outer space. Only items that are mission critical and have no suitable alternative are allowed on board without passing the test.
This is similar to how we select materials down here on firm ground. Companies have to follow safety regulations when selecting furnishings and building materials, and how those materials withstand open flames is a major consideration. We are, however, a bit more forgiving down here. The lowest level of flammability doesn’t always win the day, though it does make a stronger case.
Fire Detection Placement Is a Bit Different
Down here on Earth, smoke rises, which is why we typically install our smoke detectors on the ceiling. That’s not the case in space, however. The flow of air is strictly controlled within the space station, so sensors are placed in the ventilation systems for the best chance of early detection.
Detectors are also placed above and close to potential ignition sources and fuel sources. In exits as well, so everyone knows which ones are safe to use for an escape and which ones should be avoided.
Placing them too close to equipment that gives off steam or dust is avoided to decrease chances of a false alarm.
Compartmentalization Is Key
A space station is an island in a very hostile environment. Therefore, it requires engineering systems that are very delicately balanced.
Since you can’t simply pipe in oxygen from outside the station (since there is none), it has to be contained, supplied, and managed carefully. This makes oxygen a scarce and precious resource, and fire an especially big risk since it will burn up that oxygen. Not only that, but the presence of oxygen will make a fire spread more quickly.
The solution is to compartmentalize the fire before it can feast on the oxygen – or rapidly makes its way to other areas of the station. When a fire breaks out, ventilation systems are shut down to slow the spread and contain the fire until it extinguishes.
Fighting Fires
Fighting fires aboard a space station is an incredibly challenging task. Thankfully, astronauts have backup, since some systems can be operated remotely from Earth. If a fire breaks out, for instance, mission control can shut down electrical supply to the affected area.
Still, the responsibility to extinguish the fire will largely fall on those inside the space station. The astronauts will have to blast the flames with water mist, foam, or CO2 extinguishers. They will need to wear a breathing apparatus while doing this, since the foam spraying from the extinguisher won’t settle the way it does in our atmosphere. Instead, it will remain in the air and pose an additional hazard to the astronaut’s lungs.
(Learn more about Fire Extinguisher Classifications: What They Mean and Why They Matter)
Kill the Oxygen, Kill the Fire
While shuttling from one place to another in space, astronauts wear space suits with built-in life support systems. This gives them an advantage with regards to fighting fires that firefighters on Earth don’t have.
Fire cannot exist without three elements: oxygen, fuel, and a heat source. No oxygen – no fire. That’s why we throw flame-resistant blankets on top of fires and stop, drop, and roll when our clothes start burning – this starves the fire of the oxygen it needs to keep burning.
The same principle can be used to snuff out a fire inside a space station. The fastest and most effective way to extinguish it is for everyone to put on their helmets and void the station of oxygen. Once the fire burns through the oxygen, it dies out and the station can be filled with oxygen again.
However, this only works if the initial source of the flame has been taken care of already. If you still have fuel in contact with an ignition source, introducing oxygen back into the atmosphere will simply create the conditions for another fire.
The Last Resort: Evacuation
If things take a turn for the worst, astronauts can board shuttles and evacuate from the space station.
Down here, evacuation is prioritized during an emergency. Fresh air is just a short distance from the building and well-equipped firefighters are on their way, so it’s best to get everyone out as quickly as possible.
In space, evacuation is a last resort. Once they’re on those shuttles, safety is still a very long way away and there’s no backup coming any time soon. It’s an option taken only when every other control method has failed and there’s nothing left to do but escape while you still can.
Summary
Although it might be hard to imagine two places to live and work more different than space and Earth, the basic elements of fire safety remain very similar. Once you have a system in place to manage and monitor, fire safety management can seem far less intimidating.