Shipping containers are naturally fire-resistant, but not completely fireproof. As containers were made to withstand extreme conditions in transporting cargo, they are naturally more durable. Steel structures are naturally more fireproof than those built in wood construction. However, they would additionally need insulation and ventilation systems installed. Careful attention to the selection of finishes is also essential. Opt for fire retardant insulation, interior, and exterior building materials. It is highly important to also integrate two points of egress that conform to the fire and building codes. Should the doors need additional alteration to meet code standards, these must also be implemented for optimum safety.
The Fire Resistant Properties of Shipping Containers
Shipping containers are primarily made of a galvanized steel called, “corten steel” or weathering steel. These steel containers were particularly made to withstand harsh weather conditions and be fire-resistant, in order to safely transport goods overseas. All shipping containers already follow certain ISO standards and are already aimed at being integrated into the 2021 International Building Code. This makes containers safe from even sparks and cinders of a fire close by.
However, this does not mean that they are completely fireproof. It is recommended to place the container in an open area far from combustible items to reduce the risk of heat transfer and an indoor fire when the flame is large and burning too close to your container. (1)
The majority of ISO shipping containers do have vents fitted in the long sides of the units, at the top of the container wall, to allow for ventilation to reduce the risk of condensation build-up. All of our storage containers are inspected before they leave our yard to ensure they are weatherproof and do not leak. They also have ventilation with a minimum of two vents in each container. (1)
Newer “one trip” shipping containers are less prone to condensation than those used in multiple trips. (Simply, this means the containers only underwent one trip as opposed to several.) In the conversion of a container into a home, it is advisable however to add more ventilation to the unit to allow cross-ventilation and avoid smoke damage.
However, the material of the shipping container itself is not enough to make your structure fire-resistant. The risk of fire damage can greatly be increased or reduced according to the materials and furniture within the container itself.
Changes and Modifications to Containers for Fire-Safe Homes
Proper siting, landscaping, and planning by your building professionals can greatly help. They would place design elements, earth berms, and trees according to your microclimate and weather patterns, to study how the wind may affect any external fire.
Installing smoke detectors and fire alarms is highly recommended if not required by code. Ensuring at least two points of egress or exits opposite one another is also essential to fire safety.
The building code requires at least two exits, with doors swinging out to the direction of egress. Should your local codes require more specific detail with regard to what counts as an exit and what doesn’t, these must be strictly followed as well. The existing industrial container doors can be retained if there are other exits made available. As previously mentioned, a proper ventilation system meant for habitable spaces must be installed, to promote regular air exchange. (2)
Inquire about the type of finishes and insulation being used for your interiors, and check if they are flame retardant. Rockwool for example is a thermally insulating material that is also natural and acts as a fire retardant. Sheetrock and gypsum are among the less-flammable materials one can use. Opting for materials that can delay the spread of fire can make a big difference in giving more time for people to escape, and a chance for more to live. (3)
For the exteriors, the container can be cladded with non-flammable materials such as fiber cement panels. The steel container itself is also quite resilient on its own:
Note that steel will start losing its structural strength from about 500 deg C (1,000 deg F) and melts at around 1370 degrees C (2500°F) it. For that to happen, the container structure has to be exposed to open flames for quite some time, certainly much longer than the typical wildfire attack. (2)
Above is an image showing the contents of an Extruded Polystyrene (EPS) Cement sandwich panel. These are then wrapped with a 6mm thick layer of calcium-silicon, meant to last against a 1,000-degree celsius heat for four hours. (2)
Like all homes, the doors and windows are typically the weakest points of a home. Gaps naturally occur around these areas, which can make the building less airtight. Additionally, windows can easily transfer heat or worse, shatter.
If the budget allows, opt for double-glazed windows or fire-resistant glass and fire-resistant window frames. These will render higher fire safety than the standard single-glazed windows.
Examples of Fire-Safe Container Buildings
Shipping Container Home
The house below was made by American architect Doug Burdge and builder Nate Garnero. The design goal was to utilize recycled shipping containers for temporary housing. Part of the project brief was also that it needed to be fire-resistant. Therefore, they used fire-resistant metal panels for the exterior cladding. These came with style options of a sleek aluminum look, black, or camouflage style. These two (Burdge and Garnero) are known for their modular and prefabricated accessory dwelling units. (4)
This was built in response to the Woolsey Fire in California in November 2018. This sleek, functional piece was dubbed the “Buhaus”, a term that combines “Malibu” and “Bauhaus” aimed at a higher standard and level of design for shipping container homes.
The home totals to a 160 square foot area and can be fitted into an off-grid home (being reliant on alternative energy rather than the standard power grid). The units are available for pre-order and have been shipped since late 2020. (4)
For more details on this fire-resistant container home, check out this video Buhaus Fire-Resistant Container Tiny Home- Burdge Architects – YouTube
Shipping Container Fire Station
Cities all over the world have begun using shipping containers for fire stations. This is strategic in being able to maximize its modular nature allowing spatial flexibility of floor plan layout. Its mobility also helps should fire stations need to relocate regularly. It is also preferred for its structural durability and innate strength against extreme weather conditions.
Just like container homes, container fire stations need extra attention to the insulation used.
It must be good in regulating indoor temperatures while not being susceptible to catching fire. A few of the most commonly used for container insulation are, fiberglass, rock wool, and spray foam. These are effective in keeping the heat out while remaining fire-resistant (5)
Also important to note is attention to the shipping container doors. As they are, their steel nature makes them naturally fireproof. They would need however to still add another point of egress as well as include self-closing mechanisms to better control the flames from escaping. (5)
References
- 5 Questions You Might Have About Shipping Containers & Fire Safety (secure-rite.com)
- Fire Safety of Container Houses – iContainerHome.com
- Shipping Container Homes – Fire Resistant | ContainerHomes.Net
- Shipping container home Buhaus is designed for fire-prone areas – Curbed
- Can Shipping Containers Be Used for Fire Protection? | Gateway Containers (gatewaycontainersales.com.au)
