"Fireproof" is a common marketing claim. What do the facts say? This guide is part of our metal seed phrase backups section.
How hot is a house fire?
House fires commonly reach about 600°C to 1,100°C (1,100°F to 2,000°F), with peaks in some places. So any backup should comfortably exceed that range.
How materials compare
| Material | Approximate melting point | Fire verdict |
|---|---|---|
| Paper | Ignites near 230°C | Destroyed |
| Plastic | Melts at low temperatures | Destroyed |
| Aluminum | 660°C | At risk |
| Brass | 900 to 940°C | At risk |
| Stainless steel 304 / 316 | 1,370 to 1,450°C | Survives |
| Titanium | 1,668°C | Survives |
Melting is not the only issue. Letters can blur from oxidation, and mixed materials expand at different rates, which can distort a device.
Water and floods
Stainless steel and titanium are not bothered by floodwater. Paper, on the other hand, may survive for a while if sealed in a bag, but it is at real risk. Keep in mind that floods can sweep things away, so a secured location matters.
Corrosion
Good stainless steel resists rust, with 316 better than 304 near salt air. In his fourth round of tests, Jameson Lopp found corrosion testing uneventful, since the devices did not react strongly to the acid. Beware of low-quality steel or plated metals, however.
Crushing and impact
A burning house can collapse, and heavy debris can crush anything left in it. Public stress tests suggest that this is where designs differ the most. Solid plates with stamped letters hold up well. Tile systems can bend, jam or spill their tiles, in which case your words are scrambled.
Theft and coercion
No metal resists a thief. A fire-rated backup is also useless if someone finds it. Plan for that separately, using where to store your phrase and physical threats.
Checks you can do
- Read the maker's material grade, and look for independent test results.
- Prefer solid construction to loose parts.
- Do not rely on "fireproof" claims that give no details.
- Keep copies in different places, so that one disaster cannot take them all.
Our comparison and guide to tiles and plates go further. If you are comparing with paper, read paper vs metal.