How are shipping containers made?

Shipping containers. As Tony the Tiger would say, “they’re great”. You can store things, move things, build things or even live in one – all uses we’ve explored throughout this blog series. However, there’s something we’ve never quite addressed in the detail it deserves: how are shipping containers made? nnIt may seem like a simple answer – four walls, a floor, a room and a door (plus a tasteful paint job) – but the reality couldn’t be further from the truth. It’s a process that takes time, care and a great deal of exceptional planning. So put on your metaphorical hard-hat and join us in the container factory. Who knows, it might just stop your mind from being blown wide open. nn n

Step 1. Conception

nBefore the doors of the factory are even unlocked, a container needs to be designed. This normally takes place in the HQ of the manufacturer, with a team of specialist designers and engineers sketching up 2D plans followed by 3D renders and blueprints. Designed to meet strict ISO standards these will normally be prototyped before being signed off for large-scale manufacture. nn n

Step 2. Creating Sheets

nShipping containers begin their journey as huge coils of steel sheeting, stored like mammoth Christmas ribbons ready to be unravelled. As they are unrolled they are cut into large pieces by industrial cutters. The edges are then smoothed off to remove sharp protrusions and ensure uniformity. Following this, workers move in and use high-pressure sand/pellet blasters to remove imperfections from the surface. This allows a flawless layer of primer to be added before the sheets are moved into intermediate storage. nn n

Step 3. Forming the base

nWhen the next stage is ready to begin, sheets are taken and pressed into U-shaped pieces, an incredibly strong shape that forms the base of the… well, base. The corner posts are formed of more pressed beams, welded together and tested under a hydraulic press to withstand 97 tonnes of pressure per square metre – the weight of 12 stacked containers. Following this, top and bottom side rails are welded to fasten the walls to the understructure. nn n

Step 4. Adding the walls

nThe walls themselves are created from 11 pieces of sheet (for a 40 ft container) each, welded together by hand before being attached to the frame. At this point inspectors from the international standards agency Bureau Veritas abseil in through the windows demanding that everything be put on pause… probably. Armed with tape measures and an eye for detail verging on neurotic, they’ll make sure that everything conforms precisely to ISO standards. From the height of the walls to the depth of the wall indents, nothing escapes their scrutiny. The result is that only the highest quality is maintained throughout the process. nn n

Step 5. Things begin to take shape

nOnce the inspectors have been ushered off back into the corner, the rest of the container can be assembled. First the door frames and panels are welded together, closely followed by the front wall panel and frame. No less than 37 cross members are used to connect the bottom two side rails, creating a solid base to which flooring can later be attached. On the factory floor it all comes together. All that’s left is the roof. nn n

Step 6. Roof assembly

nUnsurprisingly the next step is to add the roof onto the container. This is a precarious operation involving a specialised crane within the factory, slowly lowering the roof onto the rest of the container. Assembly is a carefully controlled process, with many workers in place ready to manually adjust its placement as it comes down. It’s just as well, for inspectors are once again ready to swoop in and check the ISO standards are met. nn n

Step 7. Getting that smooth finish

nSteel may be strong but it still needs some protection from the corrosive power of the sea and rain. It’s with this in mind that the assembled container is sent to a blasting chamber, where any imperfections are removed through the firing of tiny metallic pellets. After this, workers move in to sand away any final lumps and scratches by hand. nnSeams are specially pretreated before the entire container is moved into the first of three rooms. The first is a paint room, where an even coat of primer is applied all over the outside of the container. The second is another paint room where a final coat is applied. The third chamber is called the drying chamber, a heated room where the primer can dry thoroughly without running. nnOnce the containers have fully dried they are moved to a painting room where workers apply finishing touches to areas where paint has been unable to fully reach – the inner frame of the door for example. ISO inspectors appear from the plumes of paint to make sure that the coating is of the correct thickness – down to the nearest micrometer. nn n

Step 8. Sprucing up the place

nThe wooden floorboards used in shipping containers are created using a method worthy of their very own explainer, and we (mercifully) won’t go into the process here. Suffice to say, they come in ISO certified tiles and can be made from any number of woods, often tropical hardwoods such as Keruing or Apitong. These are assembled then screwed into the crossbeams that form the foundation of the shipping container. For all intents and purposes the container is now finished, however there are a couple of formalities to deal with first. nn n

Step 9. The final touches

nLike an army of ants, workers swarm all over the container, adding the manufacturers logo, registration information, height and capacity mark using stencils and/or stickers. Following this, door seals, handles and locking bars are fitted, in addition to silicone sealant around the seams of the container. nnSpecially made vents are added to the corners of the container, allowing air to circulate around the container while preventing splashwater form making its way inside. This is important as salt water can lead to corrosion as well as the spoiling of goods inside. nn n

Step 10. Testing

nIt’s all very well building a shiny new container, but it’s ultimately for nothing if it fails to perform to the standards expected of it. This is why containers are taken at intervals and subjected to load testing. Meanwhile, every container goes through the ‘splash test’, a chamber that looks a little like a rather uninviting water-park attraction, to see if it shows any sign of leakage. nnIt is only following these tests, and another ISO inspection (of course), that a container will be anointed with a CSC inspection certificate. This mirror-like plaque indicates that the shipping container is finally ready for use and is the gold-standard in ensuring quality around the world.nn nnnSo there we are. End of the road, we hope you enjoyed ride. If you’re interested in finding out more, or fancy getting hold of a high-quality shipping container of your own get in touch with our friendly team of experts. We’d be delighted to help. We’ll need that hard-hat back though.