Are Container Houses Flammable?

Whether container houses are flammable depends on the materials used for their construction. Container houses built with flammable sandwich panels are highly flammable and pose a significant risk, while those using fire-resistant materials can effectively delay the spread of fire.

1. High risks associated with container houses built with flammable materials
Some illegally modified residential containers use flammable sandwich panels such as polystyrene and polyurethane foam to save costs. These materials have low ignition points and poor flame resistance, and can quickly catch fire due to electrical welding sparks, cigarette butts, or high temperatures. For example, in the 2025 fire at a container shack in Linping District, Hangzhou, the owner's cash and documents were destroyed; in the 2018 fire at a container activity house in Binhai New Area, Tianjin, two people died. When these materials burn, they produce molten, deformed droplets that exacerbate the spread of fire, and their combustion products are highly toxic, easily leading to casualties.

2. Fire-resistant materials significantly enhance safety
Compliant container houses should use A-grade fire-resistant materials such as rock wool boards and fire-resistant cotton to fill the panel cores, with a much higher fire resistance limit than flammable materials. For example, national standards require container activity houses to have a fire rating of at least B1, while products from leading manufacturers can reach A-grade standards, effectively delaying the spread of fire and buying time for escape. In addition, steel-structured houses using A-grade rock wool fire-resistant panels can meet fire inspection requirements for residential and office scenarios.

3. Other fire risk factors
In addition to materials, the fire risks of container houses are also related to the following factors:

• Electrical hazards: Behaviors such as unauthorized wiring, mixing high-power appliances, and using bottled gas indoors can easily trigger electrical fires. For example, the container fire in the industrial park in Anci District, Langfang, was caused by an electrical circuit fault at the switchboard igniting weeds.
• Structural enclosure: Container structures are relatively enclosed, with poor heat dissipation, and heat accumulation can easily generate high temperatures, creating conditions for fires. If the container is loaded with dangerous goods such as lithium batteries or chemicals, they may explode under high temperatures, forming a three-dimensional fire.
• Difficulty in escape and firefighting: During a fire, toxic smoke gathers, making it difficult for trapped people to escape; the collapsed iron sheet wrapping structure increases the difficulty of firefighting, making it hard for water cannons to penetrate inside.

4. Safety usage recommendations

• Prioritize container houses made of A-grade fire-resistant materials (such as rock wool and fire-resistant cotton).
• Avoid electrical welding operations near the container body, protect wires with sleeves, and use metal-plated zinc boxes for sockets and install them openly.
• Maintain a spacing of at least 6 meters between container houses, and equip them with simple firefighting equipment and smoke alarms.
• Regularly inspect electrical wiring, avoid unauthorized wiring, and do not stack flammable and explosive items.