Monthly Archives: April 2014

Gun Safes and Fire: Seals, part 2

Below is a smaller portion of the test curve which was shown in the previous blog.  Note how with the three inferior safes the inside temp shoots almost straight up at the beginning of the test.  Then at about four minutes the curve turns back down slightly before shooting up again.  This momentary reversal happens when the expanding heat seals get hot enough to expand.  It does help, but it is clearly inadequate.

Fire Test Chart

If there is a large gap between the door and the door frame, or the door does not close snugly, then heat and smoke will just pour in. In theory when the insulation gets hot enough to release moisture it provides a degree of cooling. And the resulting water vapor should create a positive pressure to keep really hot air from coming into the safe.  But these affects are not enough to overcome poorly designed doors which do not seal.

Gun Safe Seals 006

So why did the American Security safe perform so well?  First, these safes have plate steel doors that have tight tolerances so the doors fit properly.  Second, these units have two types of seals.  They have an expanding seal like other safes (top edge of door in photo above). But they also have a cold seal (in door frame) that keep out heat and smoke even before the expanding seal gets hot enough to work.  Makes perfect sense, doesn’t it?  None of the test safes were by Fort Knox, but most Fort Knox gun safes also use double seals.  The inner seal (see photo below) expands, while the outer seal is a fin-type which is very air tight all the time.  Graffunder gun safes use double seals, too — see earlier post.

Gun Safe Seals 001

Why don’t other safe manufacturers use double seals?  Some choose to sacrifice real protection in favor of lower costs.  When buying a gun safe, make sure the door fits properly and make sure it has both hot and cold seals

Gun Safes and Fire: Seals Are Important

Just as important (maybe more important) as the insulation used in gun safes, is the type and number of seals used around the door.  Some manufacturers claim to have terrific fire ratings – numbers made up based on the amount of drywall they use – but then poor fitting doors and inadequate seals allow heat and smoke to rush to in during a fire.


This portion of a fire test graph illustrates my point perfectly.  It comes from Intertek ETL Laboratories, an independent testing lab.  Results were released this January for fire tests done on four gun safes in December, 2013.  Temperature is shown on the vertical axis, time on the horizontal.  During the test the furnace temperature was raised to 1200F in 8 minutes, then held steady until the end.  Temperature sensors were located inside each unit 7” from the top.  A safe is considered to fail when it’s inside temp hits 350F.

Looking at the test curves from right to left, the curve furthest to the right is for an American Security BF gun safe.  This safe lasted for 126 minutes before the internal temp reached 350F – over two hours!  I cannot name the other manufacturers here, but they are very well known.  The next curve to the left is a top-of-the-line unit with a 2.5 hour “fire rating”.  Few companies claim to have a fire rating that high, but when this safe was tested by ETL it failed in only 69 minutes – less than half what the manufacturer claims.  The next safe has a 60 minute rating but it lasted only 47.5 minutes.  The final unit is said to have a two hour rating but, incredibly, it failed in just 9 minutes!!  That’s some kind of great fire protection, isn’t it?

Next time:  Explanation for the successful test and the failures.