What Are Fireproof Safes Made Of?

Fireproof safes are a great way to ensure your valuables are protected and will remain intact in case of a fire. However, have you ever wondered what they are made of? And are they all made according to the same standards?

What are fireproof safes made of? Fireproof safes are made of two skins or layers of steel filled with non-conductive and heat-resistant liner. The liner can be made of different materials like gypsum, perlite, vermiculite, cement, or diatomaceous earth. Cheaper fireproof safes can be made with hard plastic inner skin covered by a heat-resistant liner.

What Are Fireproof Safes Made Of

But are terms like “fireproof” and “fire-resistant” just tossed around, or are these safes really made from materials that can resist fires?

You are keeping all your valuables in one small space, so it is important to know and understand what the makeup of those safes is. Safes will vary in price, and there is a good reason for that as that reflects how they are made and what materials are used.


What Materials Are Used to Fireproof Safes?

People in the past also had valuables that they wanted to be protected, so it should not be a surprise that safes have a long history.

However, in the past, safes used to be made from different materials like wood, for example. Later, people started making safes out of iron.

There were also safes made from bricks, stone, ceramic and other materials which provided protection against fires.

Most safes today are made from steel, which is an alloy containing iron and carbon, but other metals can also be used like chromium and tungsten.


Fireproof Safes vs. Regular Safes

A fireproof safe is not built in the same fashion a regular safe is. While standard safes may be made from just solid steel, this will not provide much protection to the valuables stored inside if a fire broke out. As the steel will simply heat up, raising the temperatures inside to the point where everything catches fire.

Because of this, safes that are designed to withstand fires are built with a fireproof liner. They typically have two skins, an outer skin, and an inner skin. The space between the two skins is filled with a fire-protecting liner designed to prevent the heat from easily getting transferred inside.

The inside of the safe will still get very hot, just not as hot as it would with a standard safe.

Safes made from a steel alloy that has tungsten in it may be more durable and provide better fire protection as tungsten has a very high melting point. Still, a good liner is required to protect the inside of the safe.

The most commonly used materials to fireproof most home safes are gypsum, perlite, and vermiculite. These materials are used because they offer good protection against fires while remaining fairly lightweight and inexpensive.


Cheaper vs. Expensive Fireproof Safes

Cheaper fireproof safes are often made from internal hard plastic skin covered by concrete or gypsum. These can be effective but only when exposed to smaller fires.

On the other hand, the more expensive fireproof safes can use mixtures of gypsum, ceramic wool, fiberglass, vermiculite, cement, and diatomaceous earth for better temperature insulation and will be made of higher-grade and thicker steel.

The thickness of the steel and insulation materials used can vary. A thicker safe will have higher burglary protection, and a thicker liner can provide more heat protection.

Some of the toughest safes are made with 6 to 10 gauge steel plates. On the other hand, 14 to 20 gauge steel can also be a more cost-effective option, but the steel is thinner.


What Properties Should the Materials Have?

Regardless of how a fireproof safe is made, one of the issues that pose the biggest problem is that while it should be capable of withstanding high temperatures, it should also provide good insulation in order to keep the content inside as cool as possible.

The fire itself does not have to enter the safe to really damage what is inside. Many things can combust simply due to the high temperature.

In short, this means that the materials used for the making of the safe need to serve two main purposes:

  1. The materials used need to be capable of withstanding high amounts of heat and be incombustible.
  2. The materials need to be capable of insulating the inside from the high temperature on the outside.


What Is the Most Popular Fire Insulation Material Used in Safes?

Most fireproof safes are made with a thick interior lining of gypsum. Gypsum is considered among the best materials for fire insulation. Hardened gypsum usually contains high amounts of water, and when exposed to high temperatures, the water in it is slowly being released.

As the water is gradually being released, it keeps the gypsum temperature low, thus keeping the internal parts of the safe cooler.


Are Fireproof Safes Also Waterproof?

Fireproof safes are made from materials that protect against the high temperatures emitted by fires. However, the majority of fireproof safes are not waterproof. Some fireproof safes have liners that can expand when exposed to heat, making them fairly waterproof.

Here’s the thing.

Some fireproof safes have an intumescent liner that will expand and completely seal the safe after being exposed to high amounts of heat to keep the temperature of the internal atmosphere low.

However, if not exposed to heat, most fireproof safes will not be sealed tightly enough to prevent moisture from building up inside or water from seeping in.


Is There a Difference Between Fireproof Safes and Fire Resistant Safes?

Although “fireproof” and “fire-resistant” are terms that sound very different, it is generally considered that when it comes to safes, in particular, there is not much of a difference between a fireproof safe and a fire-resistant safe.


Are fireproof safes burglar-proof?

Fireproof safes are usually geared toward protecting one’s valuables, keepsakes, money documents, and other belongings from fires.

However, not all fireproof safes are designed to provide the best burglar protection since they can be made of thin steel or hard plastic, which does not make them useful against theft.


What Are Room Sized Fireproof Safes Made Of

Large volume safes—read bank vaults—are usually the most sophisticated and can have the best levels of fire resistance. For example, some of these safes can have a fireproof rating of class 125-4. (more on that in a bit)

To provide such a level of fire resistance, these safes are often made of different materials, like steel-reinforced concrete. The core of the safe can be made of ceramic fiber known for its high levels of temperature insulation.


How Long Can Fireproof Safes Last?

The term fireproof does not mean the safe can withstand the heat emitted by fires forever. Even if a safe is labeled as fireproof, it can eventually succumb to the fire.

Usually, most household fireproof safes will not last more than 30 to 60 minutes. Higher-end fireproof safes can last up to 4 hours.

High-quality fireproof safes are usually tested by the Underwriters Laboratories (UL). This is why it is recommended to choose safes that have a UL rating.

The UL certification means the safe’s fire-resistant capabilities have been tested in a controlled environment.

So even if you don’t know what a particular safe is made of, you can still find out its capabilities by checking its UL class rating.

Overall there are three UL class ratings:

  • Class 125 rating
  • Class 150 rating
  • Class 350 rating

Each of the ratings represents the temperature on the inside of the safe that can be maintained (125°F, 150°F, and 350°F respectively) for a specific amount of time during outside temperatures of up to 2,000°F.

The time frame follows the rating class.

Usually, most home fires can reach between 1,000°F to 2,000°F.

Fire departments respond quickly. Nonetheless, a house fire can sometimes last a really long time. This is why it is recommended to go with a safe that has a minimum rating of at least 1 hour.

For example, a Class 350-2 means the safe will keep the temperatures inside the safe below 350°F for 2 hours.

The Class 350 safes are ideal for paper because paper will auto-ignite at temperatures around 450°F.

Class 150 and 125 are used for storing more sensitive objects that can get damaged by higher temperatures like photographic films, magnetic tapes, compact disks.

To provide the necessary protection, these safes need to have all their components rated the same class of fire protection—including the door. Safes rated Class 125 usually require a double door assembly because there are no single safe doors rated Class 125.

That being said, if there is enough space, a smaller safe can be placed inside a bigger safe which can improve the fire protection capabilities of the smaller safe.

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