To save costs, most gun safe manufactures use $10 to $20 of drywall (Sheetrock) as fire lining and then charge you a premium for it.
Fireproof gun safes offer mediocre fire protection and can not meet industry standard tests for fireproof safes. So, gun safe manufactures basically make up their own ratings out of thin air. It is useless to compare gun safe fire ratings from different manufactures.
This article will show you the truth about gun safe fire ratings so that you don’t overpay for protection you’re not really getting.
This is the third article in the series What You Need to Know Before Buying a Gun Safe.
Myth: A fireproof gun safe will protect my guns from fire.
Gun safes offer less protection than you think — much less.
It goes without saying that no safe is truly “fireproof”, every safe has its limit and will fail at some point depending on how it’s constructed. There are many variables when it comes to fires, no two are the same. In most home fires where the walls collapsed, the contents of “fireproof” gun safe have totally burned up. But you can also find some examples where cheap fireproof gun safes made it through less serious fires with no loss. In some fires gun safes with thick steel but absolutely no fire insulation survived. It all depends on the specific details of the fire.
Because of the variability from fire to fire, it is difficult to determine how much protection a gun safe gives you by looking at what happened in fires. This is why standardized fire ratings are so important. These independent tests are designed to emulate a common worst case scenario to give your valuables the best chance of surviving regardless of the type of fire.
There is a well-respected fire rating standard in the safe industry, let’s take a look at it.
A Real Fire Safe Rating: UL 72
Underwriters Laboratories (UL) 72 is the Test for Fire Resistance of Record Protection Equipment, including safes.
UL 72 Classes
There are three classes depending on what you are protecting.
|UL 72 Class||Inside of Safe Must Stay Below||Designed to Protect|
|Class 350||350 °F||Paper.|
|Class 150||150 °F|
85% Relative Humidity
|All above and non-paper records such as computer disks and photos.|
|Class 125||125 °F|
80% Relative Humidity
|All above and flexible computer disks.|
UL 72 Duration
For each class, there is an associated time rating: 30 minute, 1 hour, 2 hour, 3 hour, or 4 hour. Note that this time rating is not the length of the actual test; the actual UL 72 testing can take up to 80 hours!
UL 72 Ratings
There are four types of test which may be performed for UL 72.
- Fire Endurance Test – This is the standard fire protection test.
- Fire and Impact Test – An additional test where the safe is dropped from 30 feet, to simulate a drop from a 3rd story into a basement in a severe fire. Note that in a fire, heavy beams and other items may also fall on a safe. So, impact resistance is important for a number of reasons.
- Explosion Hazard Test – Required test to ensure that the safe will not explode in a rapid heating situation from the buildup of pressure inside the safe or safe walls.
- Combined Explosion and Impact Test
UL 72 Test Procedure
What goes into a real fire test?
Fire Endurance Test Procedure
- Safe to be tested is loaded with loosely distributed paper and/or computer media.
- To measure interior temperature, the safe is fitted with thermocouples at the bottom, at the top, and all four side walls. For Class 150 or 125 tests, two electronic humidity sensors are included, each 18″ from the top and bottom, located mid-way between all side walls.
- Class 150 or 125 safes are conditioned for at least 12 hours before the test in an office climate. This ensures the safe interior at the start of the test is between 65 and 75 °F with relative humidity below 65%.
- The safe is placed in the oven.
- The oven temperature is increased at a carefully monitored rate shown in the Oven Temperature Ramp plot. Care is taken to make sure the heat is distributed equally to all six sides of the safe.
- After the final temperature of the test is reached (i.e. 1850 °F for a 2 hour rating), the oven is shut off.
- The test continues as the safe is left in the unopened and still very hot oven for up to 68 hours until the internal temperature of the safe falls significantly.
- Only safes whose internal temperature (and humidity for Class 150 and 125) stays below the test limits are awarded certification and become UL Listed.
- The safe is opened and the contents are examined to see if they’re still in usable condition. The safe interior components and walls are examined for heat and humidity damage.
- To keep the UL label, a sample safe may be pulled out of production one year later and retested.
Many safes fail the UL 72 test at Step 7, as the safe is still absorbing heat from the hot oven. In a real fire, the safe may be absorbing heat still from the smoldering remains of the structure.
Fire and Impact Test Procedure
If requested by the manufacturer, after the safe passes the Fire Endurance Test, another sample can be tested for Impact.
- Safe is prepared as in the Fire Endurance Test.
- Safe is placed in an oven and heated for the duration shown in the table.
- Within 2 minutes, the safe is removed from the oven and dropped from a height of 30 feet onto a pile of broken brick on top of concrete.
- The safe is examined for cracking of fire insulation and opening of interior walls.
- The safe is placed back in the oven upside-down to simulate landing in different orientations after a fall.
- The safe is re heated again based on the specifications in the table below.
- After the specified duration, the safe is allowed to cool, then taken apart to examine the internal condition, fire insulation, locks, and the condition of the contents.
- To keep the UL label, a sample safe may be pulled out of production one year later and retested.
|Fire Endurance Test |
Rating (All Classes)
|Impact Test Oven Temperature||Impact Test Heating Time|
|30 Minute||1460 °F||20 minutes|
|1 Hour||1550 °F||30 minutes|
|2 Hour||1640 °F||45 minutes|
|3 Hour||1700 °F||60 minutes|
|4 Hour||1700 °F||60 minutes|
Explosion Test Procedure
All safes tested for Fire Resistance must pass the Explosion Test.
- Safe is prepared as in the Fire Endurance Test, but left outside of the oven.
- The test oven is preheated to 2000 °F.
- The oven door is opened and the safe quickly put inside and the door closed.
- The oven remains heated for 30 minutes, then is allowed to cool. No explosion can occur.
- The safe is opened and examined.
The manufacturer may elect to combine the Impact and Explosion tests. UL will heat the safe for the explosion test, then drop it, reheat it and cool it.
From what I’ve read, the cost of having a UL 72 test performed is around $60,000, plus a few safes now and possibly a couple more a year later. Once a safe model has passed UL 72, UL will allow the rating to apply to identically constructed units ±50% of the tested capacity. This cost is required whether or not the safe pass the test, and multiple tests at repeated expense may be required before the manufacturer finally gets it right. This represents a substantial investment on the part of the manufacturer.
If you buy a safe with a UL 72 Fire Endurance rating, you can have confidence that you have a good level of protection in a fire. Unfortunately, virtually no gun safes are UL 72 Listed. Those that are UL 72 listed are true safes with B-Rate or higher burglary ratings.
As you can see UL 72 fire tests are pretty thorough. To meet these stringent requirements, fireproof safes must be well built.
True Fire Safe Construction
Due to the expense of testing, the design of UL 72 fire safes don’t change very often. Instead these safes use conservative, tried-and-true construction methods, much like your favorite firearms.
The vast majority of true fire safes use a true composite construction — fully welded inner and outer steel shells with a poured concrete amalgamate fireproofing in between. During pouring, the safe is vibrated on a shake table to get out the air bubbles. Then the fireproofing is baked in an oven and allowed to harden. Once hardened, the fireproofing directly supports the weight of the safe and interior contents. There is no need for steel frames and supports, as these can transmit heat from the outside to the safe’s inside in a fire.
During construction, the inner shell is supported by spot welded barrier contact pins, which temporarily hold the inner shell in place while the fireproofing material is poured. The barrier contact pins used to hold the inner liner provide a negligible heat pathway. Also, the concrete amalgamate adheres to the steel outer and inner shells, adding strength.
Concrete is traditionally made of Portland cement, water, and aggregates — usually sand and crushed stone. For high security safes, other materials are often used as aggregates to increase the strength of the concrete and defeat abrasive cutting tools, but these additives can increase heat transmission. For fire safe concrete amalgamates, materials like vermiculite, perlite, fiberglass are mixed into the fireproofing. These materials absorb heat in a fire and reduce heat transmission, but usually weaken the concrete mixture. Manufacturers trade off security and fireproofing in formulating these proprietary concrete blends.
UL 72 Class 150 and Class 125 fire safes have the additional requirement to maintain low relative humidity. To construct these fire safes, generally a poured outer fire lining is used to hold the internal temperature under 350 °F. Then an inner shell is used to block the humidity given off by the poured fire lining. Inside this shell a ceramic woll and/or fiberglass fire lining layer and yet another sealed shell are usually used to keep the humidity low and the inside temperature under 150 °F or 125 °F.
Now that we’ve seen a real safe fire rating, let’s compare how gun safes are fireproofed.
Fireproof Gun Safe Construction
As I mentioned in 16 Reasons to Own a Gun Safe (and 12 Reasons Not To), gun safes are not built like other safes, and this applies to fireproofing as well. It’s essential to understand the fireproofing construction process of your gun safe to figure out if it meets your needs.
The vast majority of gun safes use gypsum drywall (Sheetrock) for fireproofing. Let’s take a look at how this works.
Gypsum Drywall (Sheetrock) Fire Protection
Gypsum drywall, a.k.a. firewall, fiberboard, fireboard by gun safe manufacturers, is commonly called Sheetrock (a trademark of USG) in the construction industry. In residential and commercial construction, gypsum drywall is used as wallboard over studs. In some construction applications it’s used to slow down the spread of fire. For example, many building codes require double layers of 5/8″ or thicker drywall on the garage side of an attached garage wall.Gypsum is known by it’s chemical name Hydrous Calcium Sulfate CaSO42H2O. It contains 20.9% chemically combined water representing almost 50% of its weight. In a fire, once the gypsum gets above 212 °F, a process called “calcination” will start where the water breaks its chemical bonds and begins to boil off as steam. Converting a sold or liquid to a gas (e.g. water to steam) is known in chemistry as a phase change.
A phase change form water to steam is an endothermic reaction meaning an amount of heat is absorbed, which you know because you have to heat water to make steam. The amount of heat absorbed for a given amount of material varies from chemical to chemical, a property known as the Latent Heat of Vaporization. Cooling using the Latent Heat of Vaporization is how air conditioners work: the refrigerant is compressed and cooled to a liquid in the condenser outside your house, and then made to change phases to a gas in the evaporator coil inside your air ducts, cooling your home.
So inside a gun safe, heat from the fire is absorbed keeping the inside cool by converting water to steam. If the gun safe is constructed well enough to maintain a seal in a fire, the steam also has a side effect of adding a small pressure to the inside of the gun safe keeping smoke and hot gasses from coming inside. Until the moisture is gone, the inside of the safe will stay around 250 to 300 °F at high humidity.
After all the water in the gypsum is gone the drywall fireproofing will literally “run out of steam”. Note that gypsum isn’t like a sponge holding water, the water is actually part of the gypsum molecules. With all the water baked out, what’s left is no longer gypsum. Instead it’s a different chemical called Anhydrous Calcium Sulfate CaSO4, which will fall apart.
Some gypsum fire board is available with fiberglass reinforcement to hold it together better, but most gun safes don’t have any structural support for the fireproofing material. So, what’s left of the drywall will crumble into the bottom of the gun safe. With the drywall destroyed there will be virtually no insulation between the scorching hot outer shell of the gun safe. The contents will rapidly go up in flames.
You might hear steam and think of harmless “shower steam”, but that’s not really steam. The cloud that comes out of your shower is really fog, caused when the warm, humid air around the hot water hits cooler air in your bathroom and the water condenses. Shower fog is actually small droplets of liquid water suspended in the air. Real steam is colorless and very dangerous, as it is at least 212 °F and can easily be hundreds of degrees hotter. It will cause near-instant severe burns if it hits your skin, as anyone who’s ever opened a hot radiator can tell you. Also steam at 212 °F will cause more severe burns than water at the same temperature, because of steam’s additional energy due to the Latent Heat of Vaporization.
Steam inside your gun safe can be good or bad depending on what you have inside. Note that UL 72 Class 150 and 125 certifications limit the relative humidity inside a fire safe to protect the contents. Many things you could put inside a gun safe, like photos and electronic media, can be destroyed by this steam. If the protective steam from the drywall in your gun safe outlasts the fire, you should get in there as soon as possible before your guns rust or have other damage due to the steam.
Risks to Guns Caused by Drywall
Drywall has been found recently with many nasty chemicals. Formaldehyde is used as a plasticizer in production of gypsum slurry. Unfortunately some gypsum drywall still has high levels of this chemical after manufacturing is completed. Formaldehyde is corrosive to steel, copper, nickel, and zinc. I’ve seen anecdotal reports of formaldehyde corrosion caused by drywall in cheap gun safes.
Since many gun safes are now made in China, there’s another concern due to chemicals found in some Chinese manufactured drywall. The Consumer Products Safety Commission (CPSC) and other agencies have found high levels of pyrite (FeS2) in some Chinese drywall.
In humid environments (and probably a fire) this drywall can give off egg-smelling sulfurous gases carbon disulfide, carbonyl sulfide, and hydrogen sulfide. These gasses react with and corrode metals, especially copper and silver. 100% of the problem drywall coming from China also tested positive for the bacteria Acidithiobacillus ferrooxidans, which lives in pyrite deposits. This bacteria consumes iron and sulfur producing sulfuric acid.
It’s difficult to know what percentage of the millions of tons of drywall imported from China contain high levels of pyrite in order to figure out the odds that your gun safe fireboard has it. Some gun safes say they’re Made in the USA, but they’re actually made in China and painted here. Other gun safes are actually made in the USA but may use Chinese manufactured drywall which is installed here.
It’s difficult to figure out the risk of damage to your guns from drywall chemicals. From anecdotal reports, these problems are more common on cheap gun safes.
Limitations of Gypsum Drywall Fire Protection
Gypsum can be a decent fireproofing depending on how it is used. In fact the materials mixed with concrete in true fire safes use many of the same chemistry principals to provide fire protection. Unfortunately most gun safes don’t do a good job at implementing their fireproofing.
The first problem with gun safe fire proofing is that there is rarely structural support for the fireproofing. The concrete in true fire safes will stand up better to fire even as the fireproofing material mixed in the concrete is destroyed. By contrast drywall is constructed with nothing but gypsum sandwiched between paper. The gypsum will be destroyed as it protects in a fire and crumble into the bottom of the safe.
The best way to support the fireproofing and protect the contents from the steam released is a fully welded steel inner shell. The shells hold the fireproofing material in place even if it completely crumbles. Steel is the most expensive material in safes, so gun safe manufactures love to cut corners with thinner steel and non-continuous welds (more on this in a later article). If they’re not willing to put decent steel and welds in the outer layer, adding another steel layer to the inside of the walls is not going to happen.
A less effective but second option is gypsum fireproofing with fiberglass mesh reinforcement. Even as the gypsum crumbles in a fire, the fiberglass mesh will hold it somewhat in place. Some “higher end” gun safes come with this option, but it is still a paltry substitute to real fireproofing.
Because the gypsum drywall offers virtually no structural support to the gun safe, support beams, gussets, and other structures must be added to support the weight of the gun safe and its contents. These structures transmit heat directly from the outside of the gun safe to the interior.
Another issue with gypsum drywall is that it can fall apart due to age and interfere with the bolt work, a not uncommon cause of safesmith service calls.
If gun safes have inferior fire proofing, how do they claim 1 hour protection in a home fire? Great question.
Gun Safe Fire Ratings: X Minutes at Y Temperature
Gun safe manufacturers who use gypsum drywall as fireproofing don’t bother paying for UL 72 testing because it’s expensive and their products have no chance of passing. For safes that can’t pass UL 72, no universal standard for fire ratings testing exists in the fire safe or gun safe industry.
Severe competition in the gun safe industry is prompting struggling manufacturers to make increasingly outrageous fire protection claims. But with no testing standard, how do they come up with them?
Gun Safe Fire Test Procedures
Gun safe manufacturers make up their own fire test procedures and either self-test a safe, or have it tested by an independent testing company. Both methods are equally suspect, because either way the safe is tested to the specifications of the gun safe manufacturer.
There are many ways gun safe manufacturers can “game” their fire rating tests. The industry consensus seems to be that every manufacturer uses some sort of misleading tactic in their gun safe fire ratings, some more than others.
- Reduce the maximum temperature the gun safe is heated to.
- Change the ramp-up time so that for a “1 hour rating”, the safe is exposed to heat much slower than an actual fire. For longer duration tests also, the manufacturer will often slow the ramp-up time to get an advantage. Note from the UL 72 test, the ramp-up stays the same regardless of the test duration. In fact the UL 72 oven profile gets hotter and hotter as the test gets longer, so the test gets harder and harder.
- Use short test times like 30 or 45 minutes. Keep in mind that even in a UL 72 Fire Endurance Test, the oven is still heating up for most of the first 30 minutes. With the deceptively slow ramp up time of independent gun safe fire ratings, the safe is actually subjected to the rated intensity for a very short amount of time. Even if the safe was immediately put into a preheated oven, little temperature change occurs inside the safe for the first 10 minutes or so anyway. It takes time for the heat of the oven to transfer to the shell of the safe, then the fire liner, then the interior wall of the safe, then the air, then the contents. Obviously a short test doesn’t tell you very much about how your safe will do in a fire.
- Use an oven with uneven heating like burners in the top, and/or put the gun safe in the coolest part of the oven.
- Measure the oven temperature at the hottest point in the oven.
- Lay the safe down in the oven so it’s not subjected to the higher temperatures at the top. Also if laid on its back, the weight of the door will also artificially seal it. Apparently Heritage got caught doing this one.
- Put additional water inside the safe, wet rags, wet the drywall, etc.
- Use whatever interior contents and configuration will get them the best result.
- Play games with temperature measurements. Most gun safes fire ratings specify that the inside won’t exceed 350 °F. How can that be skewed?
- Put a single thermocouple at the bottom, the coolest part of the safe.
- Use the minimum or average internal temperature instead of the maximum internal temperature.
- Put the thermocouple in a phone book or other heat shield to skew the readings.
- Skip the cool-off test where the gun safe sits in a hot oven shut off. This is effectively skipping most of the test.
- Taking the safe out of the oven immediately after the specified amount of time. In the UL 72 Fire Endurance Test, the safe must sit in a hot oven until the inside begins to cool down, up to 68 hours. If there’s actually a fire, it’s going to be a while before the rubble cools off enough to try and recover your safe. The keypad/dial and other hardware will be melted off so you’ll need a locksmith too. The danger doesn’t end the minute the fire is out.
- Quench the safe with water immediately after it comes out of the oven. I saw a few videos online where safe manufactures do this for a 30 minute or 1 hour test. Keep in mind that a UL 72 30 minute test really represents days in an oven, not just 30 minutes.
- Not retesting after design changes. The manufacturer may have tested a safe years ago before changing the design or materials of the safe and not retested it.
- Put it in the oven and rate for whenever the inside hits 350 °F. Basically they’re rating for the time before the inside combusts. In the UL 72 test remember, even for a 30 minute rating the oven is shut off and the inside of the safe has to sit and “cook” in the hot oven for up to 68 hours until the inside starts to cool off. Since gun safe fire ratings throw away that whole part of the test, they don’t have to build the safe to a certain specification. They can cut corners and self-certify the final product to whatever rating they want.
- Anything else they can think of.
In this famous video, the manufacturer plays some of the games I mention above like not placing thermocouples in the top of the Liberty safe (which got hot enough to burn off the lining) and stopping the test, quenching it, and opening the oven immediately at 45 minutes. The quenching step isn’t shown in this version of the video, but it’s a decent illustration of the protection differences between two fireproof gun safes with the same fire rating.
So you can see that gun safe fire ratings may not tell you very much about how well your guns will be protected in a fire. Comparing fire ratings from two different companies is like comparing apples and bananas.
Gun Safe Fire Ratings and Marketing
There have been a couple gun safes which were UL 72 listed. A discontinued ProSteel model used poured insulation to achieve UL 72 Class 350 1 Hour. As far as I know of, only one gun safe with gypsum drywall fireproofing ever passed UL 72. This was an American Security (AMSEC) model made about a decade ago which was rated only Class 350 30 minutes, but AMSEC discontinued it after one year.
If a UL 72 rating is so much better, why would companies discontinue these models so quickly after spending all that money for testing?
I would guess that they discontinued it because of what sales people refer to as a customer education problem. What do I mean?
Let’s assume that competitor Brand X has a gun safe with a bogus self-certified 1.5 hour fire rating rating, although it actually has less gypsum drywall fireproofing than AMSEC’s UL 72 model. Brand X can take advantage of uneducated consumers, who might think it offers 3 times longer protection than AMSEC’s.
Let’s look at the difference between what a salesman has to do to sell these two models:
Brand X, self-certified 1.5 hour fire rating
- sell a customer the safe.
AMSEC, UL 72 Class 350 30 minute rating
- educate uneducated buyers why their safe is more expensive than Brand X. Explain why their UL Class 350 30-minute Fire Endurance Rating is actually more protection than Brand X’s self-certified 1.5 hour fire rating.
- and sell a customer the safe.
Notice that Brand X only has to sell a customer a safe, which is hard enough. That’s why in sales and marketing, a product you have to educate the customer about first before you can sell to them is considered an uphill battle. Unfortunately the issue of customer education means that it is much easier and more profitable to play to customers’ misconceptions than it is to teach them about safes and sell them a better safe. (Hopefully that’s where this site fits in.)
Because gun safes are increasingly being sold at “big box” and other stores where the salespeople had no expertise in safes, it’s getting easier and easier for manufacturers to take advantage of uneducated consumers. This is part of the reason why you’ll only see high quality gun safes at true safe dealers, where an informed salesperson can explain the differences between quality gun safes and look-a-likes.
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