Looking for Shipping Container Construction?
Robust steel shipping containers were invented and developed for transportation of cargo in the mid-1950s. Little more than three decades later, the first U.S. patent for converting shipping containers into habitable buildings was filed successfully.
Today recycled shipping containers are used in many parts of the world, including the Netherlands, U.S., United Kingdom, France, Israel, and South Africa. Furthermore, they are used for many different purposes including mobile site offices, housing, getaway retreats, shops, restaurants, coffee shops, pubs, conference and training rooms, booths for parking attendants, and clinics, schools, and even for standalone ablution facilities and innovative gym units. They are also commonly used for storage of just about any kind, including household goods; and many companies hire containers that are stored in fairly large numbers within secure locations.
Even though they are manufactured in only three standard sizes, shipping containers are incredibly versatile and they are made to strict international standards. Undeniably the strongest boxes in the world, multiple units can be combined in a myriad of ways. They can be used alongside one another or stacked to create multi-story structures. They can be reconfigured into larger spaces by removing one side of two containers to double their size. Or they can be used around an area that has a common roof structure that covers the containers as well as a central or adjacent space.
But steel shipping containers are really just an innovative building material. Other than shipping cargo and storing all kinds of stuff, from raw materials to treasured possessions, they need to be substantially modified if they are going to be used for human habitation of any kind. Doors and windows need to be fitted, and plumbing and electrics installed. All the elements of heating, ventilation, and air-conditioning (HVAC) need to be considered and incorporated into a well thought out design. Depending on the function converted shipping containers will fulfill, a comprehensive fire protection system may also need to be incorporated into the design.
While container conversion, originally proposed as a highly economic form of construction, is generally cost-effective and a lot quicker and less labor-intensive to complete than traditional brick-and-mortar or timber structures, human-centric structures demand the same technologies as traditional construction to make them suitable for purpose.
Used for emergency shelter or as a traditional prefabricated building, perhaps as a structure assembled on-site to form a fundamental site office or even basic accommodation, a shipping container will be fitted with doors and windows and will incorporate some sort of insulation. But the mechanical, electrical, and plumbing systems will normally be very basic and limited to running water and essential electrification. When container conversions are designed for housing and other more permanent functions, there is a vital need for input by mechanical, electrical, and plumbing (MEP) engineering professionals because the requirements are considerably more sophisticated.
By working closely with engineers who have the experience and capabilities to ensure that MEP systems meet local building codes and regulations, architects can create stylish, eco-friendly homes, offices, and other buildings that are both sustainable and aesthetically appealing.
Shipping Container Design
Developed by an American trucker, Malcolm McLean, who had one of the largest truck transportation business in the U.S. in the 1940s and 50s, shipping containers revolutionized the international transport industry.
While McLean’s original containers were standardized in terms of size (all 35-foot), extremely strong, stackable, and lockable, they were relatively rudimentary. But the industry developed fast, and in 1968 the first International Organization for Standardization (ISO) standards were introduced. These defined the terminology, dimensions, and ratings of freight containers as well as the way they should be identified.
As a result of these original standards, sizes for shipping containers were regulated. All general-purpose (GP) containers have a width of just under 2.5 m or 8 ft:
- 20 foot (6 m) containers that measure 20 ft x 8 ft (6.058 m x 2.438 m) and are 8.5 ft (2.591 m) high. These are also available as high cubes that are 9.5 ft (2.896 m) high.
- 40-foot (12 m) containers that measure 40 ft x 8 ft (12.192 m x 2.438 m) and are 8.5 ft (2.591 m) high. High cubes are also available.
- 10-foot (3 m) containers that measure 10 ft x 8 ft (2.991 m x 2.438 m) and are 8.5 ft (2.591 m) high
Today there are different types of containers designed for different purposes, including those intended for transporting dry freight across the oceans, and reefers that are designed for storing and transporting items that need to be refrigerated. There are also specialized shipping containers that are manufactured for the transportation of oversized or unconventional cargo. However, GP containers are the norm for architectural conversion products.
ISO 1496-1 : 1990 (E), Series 1 freight containers – Specification and testing – Part 1: General cargo containers for general purposes details how GP containers transported by sea, road, or rail should be manufactured. In addition to dimensions, the standards specify tolerances as well as specifications for every part of the container: corner fittings, the end and the side structures, the walls and door openings, and the corner fittings which are very important for easy stacking.
Other vital requirements relate to strength, loads and loadings, locking devices fitted for container roofs (or tops), as well as the securing systems that are suitable for doors. Weatherproof covers are also included in the specifications. The testing procedures used to ensure that freight containers have been correctly manufactured are included in the same ISO. They include tests for:
- stacking containers that are fully loaded
- lifting containers from the four corner fittings at the top of the box
- lifting containers from the four corner fittings at the bottom of the box
An additional 10 test procedures are provided. These enable manufacturers to test the strength of each part of the container – the end and side walls, the floor, and the roof – as well as its longitudinal restraint and transverse and longitudinal rigidity. There is also a test for checking whether it is weatherproof and for the efficiency of lifting it from fork-lift pockets and the base where grappler arms are positioned (if these are fitted).
While these standards were devised to ensure that shipping containers are strong and secure for transportation and storage before, during, and after transportation, they also provide peace of mind for those opting for a container conversion or construction project. When choosing used containers for new construction projects, it is important to assess their structural integrity, which is another role that an engineer might play. Old containers may be dented and rusted after being transported over the ocean. Also, they are sometimes coated with lead-based paints or other products to protect the metal surfaces from moisture and from salt in the seawater. These must be covered for safety reasons. However, it is common for architects to design container structures with new floors, ceilings, and walls, both internal and external. This effectively covers dings and dents and also provides an easy means to install essential insulation. That said, it is not unusual for new shipping containers to be specified for projects.
While basic plumbing and power are relatively easy to install, heating and cooling systems often present a major challenge in this environment, which is why an increasing number of architects like to team up with MEP engineers for container construction projects. Another factor is that even though containers themselves are manufactured in accordance with strict international (ISO) standards, there are also codes and regulations that must be followed when containers are converted for alternative use. These usually depend on local regulations that vary from area to area, city to city, and even country to country. Some places may not even have regulations, which might translate to a lack of control or, on the other hand, to a blanket prohibition. For instance, while codes for so-called pre-fab structures might not be strict, in many places the regulations relating to container construction could be stringent because this type of construction is largely untested.
It is essential to ascertain ground rules before going ahead with shipping container construction.
We have already mentioned that shipping container design is considerably quicker and in many ways more cost-effective than conventional buildings. It is particularly popular for designs that cater to entry-level and student accommodation. Container offices are often supplied as a “plug and play” solution where they are literally delivered to the site ready to be connected to water and electricity with no other major work required. Nevertheless, they can be customized to meet client specifications.
Additionally, they are portable and can be transported virtually anywhere in the world, including remote locations. Other advantages include the fact that most container structures don’t require extensive earthworks or foundations, although a foundation system is required. Designs are also easily adapted for sloping sites which tend to increase costs for traditional building methods. Because they are modular, individual containers can be used on their own or multiple units can be configured to make complex designs or to cater to a large number of people or multiple families.
Of course, ultimate costs will depend on the fixtures and fittings chosen for the building, as well as the sophistication of MEP systems.
We have also discussed the fact that steel shipping containers are strong and durable. In general, they are resistant to mold, fire, and the bugs and insects that so often attack timber structures.
A great advantage is that irrespective of the size and design of container structures, individual units can be converted in a factory environment and then delivered to site where the various containers in the design are assembled and completed. On-site activities might include roofing, cladding, connection and internal installation of water supply and other plumbing elements and well as electricity and gas, and HVAC systems.
The fact that freight containers are central to so-called shipping container construction doesn’t mean that traditional materials are not used. In fact, it is very easy for designers to incorporate elements constructed from timber, bricks and mortar, or even other metal. And, of course, the HVAC and MEC systems should all be sustainable and in keeping with the very same systems used for conventional construction projects.
The MEP systems of any container structure are vitally important, as is the insulation that is incorporated in the design of the structure. The challenges in terms of spatial limitations are much greater than they could ever be for a traditional brick or timber dwelling.
Consider the many pipes, cables, vents and so on that are required. These cannot be incorporated unless there is cladding at very least inside the building where the insulation and various components can be positioned.
For this reason, designers commonly include a non-loadbearing frame around the inside perimeter of the container which can be used both to hang either gypsum board or another type of drywall material. The MEP system components can then be hidden within the gap, which is done once the framework is complete. Windows and doors are also cut at this early stage.
Ventilation, cooling, and heating, which an MEP engineer will also oversee, is another major challenge, largely due to the low height of containers. Generally, standard ventilation systems can be incorporated if shallow ductwork can be concealed in a ceiling that is slightly suspended. Radiant heating and cooling systems need less space because they utilize hoses rather than metal ducts.
Rather than come face-to-face with major challenges at the installation phase, architects can reduce potential problems by teaming up with an MEP firm at the outset. It is usually worth every dollar spent.
Looking for Shipping Container Construction?
