Anatomy of a Shipping Container.

Second of 15 Shipping Container Home Tutorials brought to you by ContainerHome.info.

Tutorial 2 of 15 – Part 1 of 2 ( Preview for Non Members )

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PDF’s and links mentioned in the presentation

Bamboo Grove

This is the link to the site that used the refrigerated containers in the image shown in the video.

Whilst we don’t recommend the use of insulated containers this is a very nice looking project.

http://www.bamboo-groove.com/

Reefer containers are typically sheet and post with foam behind them.  Aluminum outer skin and either Aluminum or Stainless inner skin.  75-100 mm (3-4″) of foam.

Corrugated Web Beam

This link is not highly relevant to our ISBU discussion.

Link is included as a courtesy to the web beam manufacturer image used in video.

http://www.zebau.com/

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Transcript of  Tutorial 2 of 15 – Part 1 of 2 ( Preview for Non Members )

Todays video tutorial is all about How a Shipping Container is Constructed, Specifications and ISBU Terminology

Now I am the first to admit that this subject has the potential to be well “dry” might be a good word for it but please bear with us as we deconstruct a typical shipping container and see how its constructed I promise you that this will stand you in good stead when we get to the future videos on second hand container selection, design, repairs and modifications.

Please keep in mind it is certainly not necessary to “memorize” these specifications or terminology, we provide this information by way of a primer with an expectation that it will prove helpful to you especially if your planning a do it yourself container home project – and even if your not intending an owner builder project at least a terminology 101 should help in future conversations with trade professionals including architects and container brokers.

Although there are literally dozens of different types of ISO containers each having a unique specialist purpose in the intermodal transport industry our discussion throughout these tutorials will be focused exclusively on the standardized general purpose and high cube end opening steel shipping container ie the type most commonly used in ISBU construction

This is a general purpose ISO Type 1A end opening steel shipping container.

That is a container that completely encloses its contents by permanent steel structures and provides cargo loading and unloading access through a pair of end opening doors.

Specifically this container is a Type 1A 40 ft General Purpose or GP steel container, it’s the type that the general public tend to think of when they think about container homes.

The one side discussion I wanted to touch on here was the use of insulated containers the type used for refrigerated transport applications known in the industry as reefers and their use in container home projects.

Now we get asked this question a lot here at containerhome.info obviously because of the perceived advantages of starting with an insulated container, now I will admit that I have seen a couple of very nice projects completed using refrigerated containers however I myself have never used one

For reference here Reefer containers are usually of sheet and post construction where the post is more or less a rib. They typically have an Aluminum outer skin and either an Aluminum or Stainless Steel inner skin with 75-100 mm (3-4″) of foam insulation sandwiched between the skins.

This method of construction will show a rivet line on the exterior skin. The other style is just an in situ laminated wall of Sheet foam similar to stress skin panels.

Most people in the business that I respect will agree that it’s not a good idea to try to use these Aluminum containers for house construction purposes, that in the long run it will be easier, cheaper and faster to undertake the insulation of a standard steel container as a separate project element, my preference is based on the fact that I like the steel containers.

So typically containers used in ISBU construction projects are either 20 or 40 feet long by 8 feet wide x 8 feet high designated as GP or general purpose steel containers or they are 9 1/2 feet high in the case of the HC or the high cube steel series.

We are going to get into the advantages and disadvantages of each of these four container sizes when we get into the design videos so for now its enough to know there are only four types to select from for most ISBU projects

All ISO containers must meet a ton of different specifications and standards in order to be certified for use.

However most people are not aware that these standards are more to do with the size and strength requirements of a container than the actual detail in how they are constructed.

The ISO and IMO – International Maritime Organisation set standards around things like

- Absolute height, width, length

- Absolute strength tests

- Inspection procedures

And Certification plates and markings

However its the container factory engineers that determine

- wall, roof, floor and corrugation designs

- Paints, primers, coatings and Sealants that are used

- even what type of flooring materials are put into their containers etc

For example

Any roof or wall corrugation design may be used as long as it meets the ISO and IMO strength test.

The corrugation profile could a “w”, “v”, square, even round or oval shapes

As well any flooring material may be used as long as it meets the ISO strenght test.

The material could be plywood, birch, teak, mahogony, bamboo, metal, HDPE plastics, or any composite or even combination of these

In short there are actually many acceptable variables in container construction as long as the strength tests and dimensions of the finished container meet the ISO/IMO specifications

That said since about 2000 almost all container manufacturing factories are now located in China and as such there are fewer and fewer variations being produced as brand new containers standardized is a lot more common on profiles and materials like plywood floors and coatings not so much because of the ISO standards but because they have been distilled down to the cheapest solution to creating a durable container.

Now in my opinion it is not necessary to really understand all these ISO or IMO standards themselves in detail in order to successfully build a container home, what is beneficial however is to understand what goes into making a container that conforms to these specifications and that is what we are going to be focusing on here.

So lets get started

How does a container get its legendary strength ?

An ISO container is designed with a unibody construction to resist very prescriptive loading conditions

In general the CSC certifies the containers for the prescriptive loads they must resist for their use as shipping containers and actual mechanical load tests are conducted on 1 out of 150 manufactured containers for Quality Control.

However what too many over enthusiastic advocates fail to understand is that the containers real strength is derived not from the individual components making up the container, as you will see most of the parts are only made from 4 mm pressed steel plate but rather the sum of all the parts all working in unison together in what is called unibody construction.

The unibody construction method produces a strong, robust, lightweight, low cost structure.

Why is this so important ?

Well we are going to get into this a lot more in the modification videos but for now the question I get asked more than any other about container homes is this

How much of one side can be removed without weakening the structure?

The answer – the truth that advocates don’t seem to want to hear is

None, Zero

The moment you make even a single cut in the sidewalls or rear end regardless of location, the unibody structure of a container is weakened.

Now I accept have never meet anyone that doesnt also agree that container load tests subject the containers to far greater loads than they will ever experience in the static application we will be using them for , so this is a very manageable outcome but it’s simply bad engineering to say the structure is not weakened

When it comes to ISBU ‘s just as in the case of all modular home construction it is common for the maximum load condition in our application to be the shipping and handling loads associated with getting them fabricated, shipped and set in place rather than the load conditions they will experience at the building site however almost all apertures will require perimeter framing along with some bottom rail to top rail intermediate posts BTW an intermediate post is any reinforcement from bottom to toprail not located at a corner.

An easier way to understand this is to view the container as the separate subassemblies it is assembled in – maybe now you can see why I need you to sit through this terminology video before we can get to the fun stuff.

Dimensions

Dimensions are one of the many areas of containers that are something of a paradox you see most people would associate very detailed engineering dimensions with the manufacture of shipping containers, there is even a business that sells what they market as highly accurate to the “millimeter” technical CAD drawings of standardized shipping containers, now I have purchased a copy of these drawings and if you where going to go into the container manufacturing business I would recommend them to they would be a most valuable resource but they are not really relevant to ISBU construction because

You see although all containers seem to look the same at first glance the corrugation shapes, designs, and certain reinforcement areas can vary enough from one manufacture and the next to cause confusion with architects and designers and engineers relying on these types of drawings.

The most common example of these variations may be the side corrugation panels; some are angled, and some squared. Another common confusion is in the roof. Some have the raised oblong oval stamp design while some of the older models are quite flat and have small crossmember supports.

Because the container is believed to be an ISO standard few people realize it’s wide structural variations over the years.

As well all in service containers have an acceptable tolerance to dimensions that might surprise some people the tolerances really reflect the extremely tough working conditions in which shipping containers operate an environment where to the millimeter dimensions are quickly forgotten as impractical, these boxes get knocked and twisted and wrenched violently in their everyday lives and very quickly to the millimeter measurements are not really practical.

For example the maximum allowable difference between two diagonals on any one of the Roof, Bottom or Sides of a 40 ft general purpose container is actually 19mm, now remember that is still within tolerance for a serviceable certified container and keeping in mind our guiding principal of wanting to use a container that is as close to the end of its lifecycle as possible in the real world we see containers for sale that are up to 30 mm out on these diagonals – but we are going to talk a lot more about that in the next video on inspection and what to look for in purchasing a used container.

For now its enough to consider the dimensions in the PDF documents supplied in the download area of this tutorial for each of the four container types these will be more than enough for our purposes at this time.

So now lets go through each constructed element that makes up a shipping container and talk about any areas that might be relevant to our ISBU discussion.

Part 2 of 2 of this transcript ( and the video ) is available in the members section.