For general information on waterproof safes, and what it means for a safe to have a waterproof rating, see our article, “Are Safes Waterproof.”
Gun safes are not waterproof due to their construction:
The bottom of gun safes have holes so that the safe can be bolted into the foundation. They are there to prevent the gun safe from being removed or knocked over in an attempt to pry the door open.
In the event of a flood or fire, once water rises above the level of the floor board, standing water will get inside the safe.
Gun safe doors are not sealed water tight. In fact, many will slightly shake back and forth due to an air gap, perfectly normal.
So, if a pipe were to burst or somehow the home flood, the water can easily seep into the safe if the standing water is higher than the crack at the bottom of the door. In this case, there is no water resistance.
However, the doors do have a fire seal around them to protect the safe's content from fire. This door seal expands up to 10x when exposed to heat so that the heat doesn't enter the safe.
This will actually "seal" the door a bit and provide some water protection in the event of a fire and a water hose being sprayed on the gun safe.
The expanded fire seal will help prevent water from rapidly entering through the door (meaning, water from a hose won’t just pour in), but water may still get in, it just won't be rapid. For example, depending on the depth of the standing water on the floor, it may slowly seep in from the bottom.
Another reason gun safes are not waterproof has to do with the fire board or slurry that give the safe it’s fire resistance.
In the event of a fire, these materials release steam (see our article How do Fire Safes Work in order to keep the internal temperature of the safe below the specified temperature of the fire rating.
That production of steam has to vent out, so safes are not air tight, thus not water tight, and standing water can get in through the door.
Even without the water, the moisture released from the fire could cause “water” damage to unprotected content.
To make a gun safe waterproof, place a small certified water-rated box, water-rated bag, or oven-safe bag into the gun safe to hold the water sensitive content.
Be certain that the waterproof solution you choose can withstand that heat during a fire (see Fire Ratings Explained.
While some water-resistant bags are not ETL certified as waterproof, they are a sealed bag. So long as not completely submerged, they will give you the water protection you’re looking for within a gun safe.
Do NOT use regular freezer or storage bags, these can melt at the temperatures inside of a safe during a fire. In a fire, a fire rated gun safe can reach internal temperatures of 350 degrees during it’s fire rated period.
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