How Shipping Containers Protect Against Fire Damage

How Shipping Containers Protect Against Fire Damage

Jan 12th 2022

Fire Protection with Shipping Containers

When you think about using a shipping container to transport or store goods and possessions or even as a modular building unit, fire prevention may not be your first thought. You know that shipping containers can withstand the harsh conditions out at sea, but what about fire?

Shipping Container Fires at Sea

Sixteen severe container ship fires in the past five years and about one shipping container fire on board a cargo ship every two weeks might indicate a problem with fire resistance. However, when you dig a little deeper, you find that the problem isn't the shipping container- the shipping container actually helps keep the fire contained and prevents widespread fire damage.

Most shipping container fires at sea result from the transport of dangerous materials that haven’t met the safety requirements of using a suitably modified container. The most hazardous cargos known to generate shipping container fires include:

Explosives – including fireworks.
Gasses – such as medical oxygen.
• Flammable liquids, solids, and other materials that spontaneously combust.
• Organic peroxides and other oxidizing substances.
• Lithium batteries.

All these materials can be transported safely if in an appropriate shipping container and having notified all the relevant authorities of the nature of the cargo. Insurers estimate that 5% of shipping containers mislabel their contents as some shippers try to avoid the higher fees for shipping dangerous materials.

Despite this issue, most shipping container fires remain confined to a single container and self-extinguish. The fact that most container fires do not escalate to more severe incidents shows that shipping containers are an excellent form of protection against fires.

How Does a Shipping Container Protect Against Fire?

An unmodified shipping container is naturally fire-resistant. However, further modification when transporting hazardous materials increases protection against a fire starting or getting out of control.

Fires Inside Containers

Tests done by the US Coastguard in 1977 demonstrate that a simple wood fire inside a container is self-extinguished as the fire runs out of oxygen. However, a fire fueled by flammable liquids may result in the container becoming pressurized and exploding. Typically, the explosive force will blow out the doors without an explosive release panel. An incident of this nature killed a fire chief attending a fire at a log yard in Canada in November 2014.

The key takeaway is that most simple fires inside shipping containers self-extinguish and remain contained inside the metal box without spreading to the surrounding areas.

Storage of some materials inside a storage container requires modifications for ultimate safety in a fire. Still, these are relatively straightforward when you do a proper risk assessment and follow best practices.

A storage container is solid and rigid – they survive drops, extreme weather events and are secure against intruders. If a fire inside the container generates hot gases because of the contents and insufficient ventilation, then the expanding hot gas pressurizes the container. Assuming the door doesn't explode, opening the door under pressure is a terrible idea. A strategic explosion panel provides a safe way for the container to depressurize. If the worst happens and fire creates explosive potential inside the storage container, the explosion panel will save the day by allowing the hot gases to vent safely.

Fires Outside Containers

Typically, a shipping container is left standing, intact, and secure after a fire passes or an arson event. Corten steel has some properties that help a storage container to be fire-resistant:

• Thermal conductivity is four times less than that of aluminum; external heat will get through the steel walls but at a lesser rate than other metals.
• A similar thermal expansion to concrete meaning, like concrete, it retains its shape when exposed to fire.
• Nonflammable when exposed to fire.

A spark or cinder falling on a shipping container will not set the container alight. Still, if you allow twigs and dry leaves to accumulate on the roof, these may burn, but the fire will not burn a hole in your storage container except in exceptional circumstances with a hot fire burning for hours or days.

You can expect the contents of a shipping container to remain free from smoke damage unless the shipping container is inside a wildfire for a prolonged time. In this case, the heat transfer to the contents is more of an issue.

Since steel is not only stronger than aluminum but also has a lower heat conductivity, your items will be kept safe, even during some of the most extreme wildfires. Steel can withstand temperatures up to 1,000°F before softening and 2,500°F before beginning to melt.

The average forest fire burns at around 1,472°F, meaning your contents inside the container will be kept relatively safe from fire damage. As an example, items stored in cardboard boxes are prone to spontaneous combustion if the surrounding area heats up to around 800°F. 

This further demonstrates how steel containers are more durable and fire-resistant than most other storage methods.

Applications of Fire-Resistant Storage Containers

The fire-resistant properties of shipping containers make them ideal storage units for all types of materials and possessions both at home and at work. But what are some specific applications using storage containers for situations involving fires?


Devastating wildfires can remove homes and entire neighborhoods before being put out or controlled. Many companies and architects are using fire-resistant shipping containers as modular building blocks as they give a fire-resistant structure that you can modify further to create a home that withstands wildfires.

No home will ever be 100% fireproof while providing comfortable living conditions, but you can at least have a fire-resistant home that won’t burn down easily like typical housing.

Using shipping containers as a modular building block gives you a head start on building a fire-resistant home. Still, it is best if you pair your shipping containers with other fire prevention materials and processes:

• Non-combustible coverings and insulation.
• Store flammable materials away from your home.
• Use tempered glass and double or triple glazing.
• Add nonflammable shutters for extra protection.
• Use composites for decks.
• Remove potential fire fuel from around the house.

Using shipping containers lets you build an affordable fire-resistant home in a fraction of the time than with a conventional approach.

Jobsite and General Storage

Naturally fire-resistant storage containers provide secure, protected storage that will keep the content safe from minor fires and arson that can happen on a building site or at home. Securing building timber or seasonal storage inside a storage container means that if someone burns rubbish in the area and a spark lands on your shipping container, you can relax; the container will not burn. It takes serious intention and fuel to produce a fire that damages a shipping container.

Jobsite and General Storage

Naturally fire-resistant storage containers provide secure, protected storage that will keep the content safe from minor fires and arson that can happen on a building site or at home. Securing building timber or seasonal storage inside a storage container means that if someone burns rubbish in the area and a spark lands on your shipping container, you can relax; the container will not burn. It takes serious intention and fuel to produce a fire that damages a shipping container.

Dangerous Materials

Modified shipping containers can provide secure onsite storage for many hazardous materials. Storage of combustible materials for work is highly regulated and following safe storage guidelines makes sense in a home environment as well to assure your family's safety.

Lithium batteries present fire and explosion risk but a modified storage container can combat these risks with:
• Moisture and humidity controls.
• Gas detection and removal systems.
• Fire containment and alarms.
• Explosion release panel.

One of the advantages of modifying a storage container for this purpose is the potential portability of your cost-effective battery store.

Storing flammable and combustible liquids requires:
• Additional ventilation
• Explosion relief panels
• Appropriate signage

Storing compressed gas cylinders requires adherence to strict regulations over storage and use. You can use a storage container as protective storage for these items but with the appropriate modifications in place:
• Cages to hold cylinders in vertical position.
• Additional ventilation.
• Fire containment features.
• Explosion release panels.

Explosives, flammable liquids, and compressed gas cylinders ship around the world safely and securely, but these inherently dangerous materials need careful handling and appropriate safety modifications.

Fire Department Training

The fire-resistant, modular shipping container is ideal for producing training areas for firefighters. Shipping containers can stack together, and you can create some unusual layouts to simulate some of the issues a firefighter may face in tackling a fire in a domestic or commercial building.

Fires set inside a shipping container allow training in the most effective way to deal with fires in different settings, confident that the fire is contained and not a risk to the surrounding area. Enclosing a fire inside a shipping container allows demonstrations of how fire can behave in rooms, such as fire flashover in a room without sprinklers. These shipping container training modules are also ideal for practicing rescuing people from smoke-filled rooms and teaching other fire-fighting techniques. Using shipping containers to train fire service officers is affordable and flexible compared to practicing in a traditional building.

Unique Fire Prevention

Could modified shipping containers be automatic fire preventers? Inventor Eddie Paul, an inventor and stuntman, converted a shipping container into a heat-activated firefighting system. The modified shipping container can be dropped into a fire or placed in an expected wildfire zone.

At 200°F, the walls of the container fall away, and at 212°F, fire-retardant foam shoots 164ft around the container suppressing the fire. Heat powers the process, and the container stops shooting foam when its temperature falls below 212°F.

Eddie’s unique fire-fighting sea cans use a simple but ingenious technique to make the fire itself provide the power to fight the flames.

How Can Help You?

Standard storage containers are excellent for use on jobsites, homes, and businesses and able to be converted into all building types. We have over 40 years of experience in sourcing and modifying shipping containers for our customers' innovative projects.

If you have challenging material to store or have a project that needs fire resistance, get in touch and chat with our experienced staff. We can tell you what you can and can't safely store in a regular storage container and help with designing and modifying shipping containers for when safety matters in your storage or building project.

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