Repurposing Shipping Containers
27 July 2021
Modular construction provides numerous advantages: cost savings, reduced time, improved safety, reduced pollution/waste, energy savings and sustainability. One growing sector within modular is converting shipping containers into modular buildings. Containers offer a ready-made structure designed to be transported, lifted, and stacked, and are a plentiful resource, with an estimated 11 million containers going unused. As a result, there are now homes, apartments, hotels, restaurants and other buildings being built from converted containers. While they present unique opportunities, there are regulatory issues and challenges to using shipping containers to keep in mind.
As the industry began seeking permits for buildings using repurposed containers, jurisdictions recognized they needed to address this new construction type. States and authorities having jurisdiction (AHJs) found that containers fell under modular rules and regulations and could be considered concealed construction. So, for many states throughout the U.S., inspections and approvals fall under the scope of registered modular third-party inspection agencies.
Another very important regulatory concern relates to steel. Ordinarily, approval of structural steel includes mill reports and welding specifications. However, approximately 97% of containers are built in China and this information is often unavailable. In early 2016, International Code Council Evaluation Services (ICC-ES) introduced Acceptance Criteria 462 - Structural Building Materials from Intermodal Shipping Containers (AC462), which established criteria and a protocol for evaluating reused shipping containers as a building product, providing clarity on ensuring structural integrity.
If compliance with AC462 is not an option, many projects can use a professional engineering firm specializing in container repurposing to assist with design analysis and integrating openings in the containers and other site-specific elements. These options are commonly accepted by most state agencies and local jurisdictions to demonstrate structures will meet the intent of International Building Code (IBC) section 104.11 and the International Residential Code (IRC). Additionally, the International Code Council (ICC) has published the ICC G5-2013 Guideline for the Safe Use of ISO Intermodal Shipping Containers Repurposed as Buildings and Building Components. This standard provides further guidance for code officials and designers.
There are other considerations and challenges when using shipping containers. While they lend themselves well to compartmentalized building types like apartments and hotels, there are structural limitations to the size and locations of openings that can be cut in the long sides of each unit. As a result, open plan buildings are not a good fit for container construction.
Some materials in shipping containers need special attention as well. Containers are often treated to prevent environmental degradation and insect infestation, presenting potential health concerns for future occupants. A third-party quality assurance agency needs to evaluate materials to determine if any are toxic, as well as how to handle replacing, cleaning, or sealing as appropriate for future use.
Despite some limitations, modular construction with shipping containers provides cost, schedule, and sustainability benefits that allow it to fill an important and growing niche. It has gained the support of the Modular Building Institute and a growing fan base of developers, designers, and builders. With millions of shipping containers arriving in U.S. ports every year, and many of them not making the return trip, they are a readily available resource, ripe for creative exploitation.