Home Fireproof Safe Ratings – How to Determine If Your Safe is Fireproof

Home Fireproof Safe Ratings – How to Determine If Your Safe is Fireproof

Want to Blow Up a Safe?

With these tests for your home fireproof safe, it could explode. This article tells you how to test a fireproof home safe to determine if it meets the standards for fire resistant ratings established by The Underwriters Laboratories. Please note that I use the term fireproof interchangeably with fire resistant, technically they are not interchangeable. I also recommend that you do not actually try this in your own home. It is far too expensive and dangerous.

Material Needed

1. You will need a minimum of two identical home fireproof safes. You will need a third fireproof home safe if you want to do the explosion test by itself.

2. Select some documents that you can use for a test. Make sure it is something that you can spare but don’t use blank paper otherwise you won’t know if is readable or not. I’ve contemplated using my BS degree in electrical engineering. I haven’t used it for years. If you are testing a media safe, then you may want some CDs that you got for Christmas and can’t stand. Try a flash drive and memory stick also.

3. You’ll need a furnace big enough to heat one safe at a time. If you’ve watched MacGyver or the A Team, I’m sure you can improvise. Otherwise check out a local pottery kiln.

4. Get some protective gear. Oven mitts will not do well opening a safe that has been heated to 2,000 degrees F.

5. Somehow, you will need to find some thermometers and recording devices that will let you know the internal temperature in the fireproof safe. I don’t think an Oregon Scientific weather station will work unless you are testing for the UL 125 rating. It will also need to measure humidity.

6. You will also need to measure the external temperature of the safe. Good luck finding a cheap thermometer that goes to 2,000 degrees.

7. Oh, I almost forgot. You will probably need a small crane to hoist your home fireproof safe 30 feet in the air while it is still hot. A quick release will also be needed for the drop test.

8. At the bottom of the drop test, you will need a pile of bricks on a cement slab.


Assuming you have been able to assemble all the material above, it might be good to find out what the different UL ratings mean and the criteria that will determine a successful test. Each of the ratings can be used for a fireproof safe but it is meaningless unless you specify how long the safe will meet the standard.

UL 350 – The safe must keep the interior temperature below 350 degrees Fahrenheit. That’s below the normal temperature for most paper products to burn, char or become useless.

UL 150 is the rating for tapes, cartridges, microfiche, and microfilm. In addition to keeping the interior at or below 150 degrees, the humidity must be below 85{4d40cc26d078fd4100d2daf00165e0560f17ee302de6bc2409b7ee95793dc9eb}.

UL 125 is the standard for diskettes. In this case, the temperature cannot exceed 125°F and 80{4d40cc26d078fd4100d2daf00165e0560f17ee302de6bc2409b7ee95793dc9eb} humidity. I have a feeling that this standard is a bit out of date because most people don’t store diskettes anymore.

Heat Test

The first test is to see if your fireproof home safe will protect the contents for the specified length of time. You need to start at normal room temperature and humidity. Load your safe with your test material and haul it over to your furnace.

Heat your furnace to the following temperatures (all Fahrenheit) for the test you want to run then put the safe in the furnace. Be careful, when Shadrach, Meshach and Abednego were tossed into a super heated furnace, the guys assigned to the task were killed from the heat.

o 1,550 for a ½ hour rated safe
o 1,700 for a 1 hour rated safe
o 1,850 for a 2 hour rated safe
o 1,920 for a 3 hour rated safe
o 2,000 for a 4 hour rated safe

Leave your home fireproof safe in the furnace for ½ to 4 hours. Here comes the kicker. Don’t remove the safe after the allotted time, simply turn off the heat and let it cool down inside the furnace. If you have a really good furnace, like the ones that the guys at UL have, that would take up to 68 hours.

You’ll need to record the interior temperature during the heat up and cool down phase. If it goes above the rating, your home fireproof safe flunked the test. When it gets cool enough to open, you will need to check your test contents to make sure they are still good.

Impact Test

I think the heat test was somewhat boring. The impact test is a lot more fun and doesn’t take as long. For this test, you need your second home fireproof safe. Start the same as before but the times and temperatures in the furnace will be less.

o 20 minutes at 1,460 degrees for a ½ hour rated safe
o 30 minutes at 1,550 degrees for a 1 hour rated safe
o 45 minutes at 1,640 for a 2 hour rated safe
o 60 minutes at 1,700 for a 3 and 4 hour rated safes

This part sounds like a TV game show. You now have 2 minutes to get the safe out of the furnace, lift it 30 feet in the air and drop it onto your pile of bricks. If you can see the insides through any cracks or the door, your fireproof safe flunked the second test. However, if it still looks OK you aren’t done yet.

Turn your safe upside down and reheat it again. This time you can remove it from the furnace and let it cool. Open the safe and examine the contents. If everything is OK, including no damage due to moisture, you are almost done.

Explosion Test

If you are a fan of Mythbusters on TV, then this has the potential of being the most fun. If you only bought two safes, then you will want to do this before you do the drop test.

Start with an empty fireproof home safe. Heat it to 2,000 degrees then open it and stuff the test documents, CDs or other material in really quick. Slam the door shut and keep the exterior at 2,000 degrees for another 30 minutes. If your safe hasn’t exploded you are almost done. Once it has cooled enough to make sure you can handle it, open your home fireproof safe and make sure your documents are still OK.

Congratulations, you have just proved that your home fireproof safe is indeed fire resistant.

Mythbusters Test

None of your safes are any good anymore so this is for those who like to see things blow up. Get a stick of dynamite and… No, I’m not going there. Someone might accuse me of endangering people.


It is a lot cheaper and safer to just look inside your safe and see if it has a UL sticker.