So here’s my idea: a cubic meter of water takes about 400MJ of energy to boil away. A typical house fire contains around 70GJ of energy, but most of that radiates outward. If I build a large metal box, fill it with water, and submerge a smaller waterproof box for the items I want to protect, wouldn’t that keep the contents cooler than a traditional fire safe?
This setup would limit the internal temperature to 100°C, which is way lower than the 197°C char point of paper. I know it’d be tricky to make a box that’s sturdy and leakproof under fire conditions, but it seems like it could be cheaper and more effective than traditional safes.
What do you think? Any obvious reasons this wouldn’t work?
Commercial fire safes are designed to handle this sort of thing. Also, if your items are submerged in water, accessing and storing them would be a pain, which kind of defeats the purpose.
@Pax
You’re right about access being inconvenient, but this would be for items you don’t need often. I’m thinking this might be cheaper and safer because it keeps the temperature lower and could handle bigger fires better.
@Scout
I’d bet something similar has been tested before. Fire protection has been a problem for ages, and there’s a lot of demand for it—from homeowners to governments.
The reason it’s not common might be cost, space, or risk. Maybe it’s worth exploring alternatives like fire suppression systems or materials that starve the fire of oxygen.
@Scout
You could dig a hole, build a big concrete box with a water seal, and cover it with a loose lid and a grate to keep debris out. Lift the inner box to access your items. Commercially, though, this idea wouldn’t fly because people don’t like things requiring maintenance.
I’ve thought about something similar. My idea was to place sealed water containers, like 5-gallon jugs, on top of my fire-rated safe. In a fire, the jugs would melt and release water over the safe, providing a few extra minutes of cooling. It’s not perfect but could help.
I also moved all combustible vegetation at least 75 feet from my house for added fire safety.
What about the risk of bacteria like Legionella growing in the water? That’d be a weird theft deterrent.
The water would get gross unless treated, so you’d need some kind of chemical maintenance. Imagine showing people your fire-safe water tank: “It works, but don’t touch it!”
