What are open top shipping containers?
Open top shipping containers are a specialised type of shipping container specifically designed for loads that need loading via crane / items that are to big or difficult to fit through the end doors on a standard cargo container. Also used in environments when cargo is loaded from the door side but via overhead hanging tackle and for over-height cargo (cargo that is to tall to fit inside a standard shipping container)
Generally they only have this specific use. Despite having no roof they will commonly be more expensive than a standard dry container. They are not a very good option when wanting a storage container. They will also only come in standard 20ft and 40ft sizes as they are only built in sizes currently used in the shipping industry.
It’s usually not a practical option to make a non-standard size of open top for shipping use. The equipment used at ports and depots, and twistlocks to fasten containers onto trucks won’t fit a non-standard size of shipping container. This means it will be much more expensive to move a custom sized open top shipping container.
Hard top and Soft top open top shipping containers
Open top shipping containers can come with a hard top or a soft top. (Other similar terminologies are used globally but will refer to the same thing). A soft top is a tarpaulin cover. This is the commonplace option in the shipping industry. All open tops are supplied with a soft top that covers the shipping container roof only when the cargo is in-gauge – ie not oversize and not sticking up beyond the roofline. If you have cargo that is oversize you will need to also buy in a specially made oversized tarpaulin (tarp) to go with it. For a supplier to price up and order the oversize tarp they will need details for the length, width and height for the oversize load. All tarps need to be tightly lashed as loose tarps will be more prone to damage (rips, tares and snags).
Removable door header bar on open top shipping containers
Most modern (including nearly all used) open top shipping containers now include a removable header bar above the door as standard (or a header bar that swings open to allow unobstructed access above the door line). This allows for easy loading of some bulky cargos by fork lift. As this removable header bar is an additional feature introduced by some shipping lines and leasing companies it is not essential or guaranteed under ISO specs. For this reason if you need this feature please make this clear to us and we can ensure its provided.
Door header openings are typically 6ft 2 inches / circa 1880mm above the floor line.
Floor depth on an open top shipping container
Floor depth on a 20ft or 40ft ship[ping container can vary slightly between different ages and makes of container, but typically the floor is a fair bit higher than the floor in a standard dry shipping container (one with a roof) as the floor needs extra strength in it to make up for the lack of a roof. We’ve typically seen floor depots of 170 mm / just under 7 inches in an open top shipping container.
What sizes of open top shipping container are available
For standard cargo containers, 20ft and 40ft open top containers are the only available length options. Of course as with our industry there will always be the very occasional exception but as a general rule of thumb, any custom size of open top other than the 2 standard sizes listed above will be a lot more expensive to produce than the size up, and will cost a lot more to ship than the size up. We have not yet seen a circumstance where a custom sized open top shipping container is the best option for the customer.
High Cube Open tops
The vast majority of open tops are standard height (8ft 6 high) although we believe a couple of shipping lines have introduced some high cube open top shipping containers into their fleets. As we write (2017) we have not yet seen any of these filer through into the used marketplace although we expect to see these start to be sold off as used to traders like ourselves in the early 2020’s. Even then they will remain highly specialised for many years.
ISO Codes for open top shipping containers
20ft Open tops (8ft 6 high)
ISO Codes: 22U0, 22U1, 22U6
40ft Open tops (8ft 6)
ISO Codes: 42U1, 42U6
40ft High Cube Open tops
ISO Codes: 45U1, 45U6
Getting the right soft top / tarp for an open top Shipping Container
As standard, open tops will come with a tarp that will just fit if the cargo does not stick up beyond the roofline. If your cargo is overheight (or out of gauge) the standard tarp will not properly fit onto the shipping container which can lead to the goods being inadequately protected during transit.
It will depend on exactly what you are shipping of course, but in most cases the shipper or freight forwarder will request an oversize tarp. these are specially made tarps or covers that will just fit the container when loaded with your overheight cargo. These are specially made to order and we will need the dimension of your overheight cargo in order to make a suitable tarp for you.
Lifting an open top shipping container
When loaded, open top containers should be lifted from the bottom corner castings where possible. In many cases you may get away with lifting from the top, the corner castings are strong enough but depending on your lifting gear some cranes can interfere with and potentially damage any tarp / soft top.
When lifting via crane or similar, a lifting frame or some form of spreader should be used to ensure that the chains are lifting vertically. If you lift from a single central point you risk the container collapsing in on itself under its own weight.This risk is more pronounced when lifting from the top castings.
As ever best practice for the handling and lifting of shipping containers should always be followed. This is not a comprehensive guide on the best practice and safe lifting of shipping containers.
Fork Pockets on an open top shipping containers
20ft open top shipping containers will usually come with fork pockets, and all the ones we have seen in the past are safe to lift from whilst loaded.
40ft open top containers will typically no longer come with fork pockets, although there are some designs / fleets what do have fork pockets included. Fork pockets should not be used to lift or move when loaded. The 40ft container is too big for this and you can very easily bend the container chassis into a banana shape. This will mean it cannot be used for shipping as it will lo longer physically fit onto a boat, truck or train carriage designed to carry shipping containers.
What is an offshore spec or DNV 2.7-1 spec Open top Shipping Container?
DNV spec containers, or offshore spec containers are a special design of shipping container intended primarily for the offshore oil and gas industry.
DNV containers are built to very different standards and to be frank they are very different containers (even though they may remain the same size and shape as a standard shipping container). DNV is short for Det Norske Veritas, the body defining these DNV standards, best practices and that offers training and testing for inspectors. (https://www.dnvgl.com/)
In very basic terms, DNV spec containers are designed to be transported on much smaller vessels travelling to or from oil and gas rigs. The are designed to take hits from big waves, they are designed to remain buoyant as long as possible, and they are designed to take bigger knocks that a standard cargo container. Each individual part in a DNV spec container is also traceable back to source.
Essentially, if your customer or industry requires a DNV spec containers, you will require one. If your customer or industry doesn’t require a DNV spec container you will likely want to avoid using them, as a DNV spec container will commonly cost 5x the price or a standard cargo container.
What is a modified open top shipping container?
Modified open top shipping containers are open tops which have been made by modifying a standard cargo container. It might sound simple but this involves a lot more than simply cutting the roof off as the container then requires more structural support to make up for the lack of a roof.
Typically these modified open tops will have a lower overall capacity (circa 20 tonnes max gross), more restrictions on loading and handling, and almost no resale value. They are often frowned upon in terms of quality in the shipping industry
However on the plus side they will often come in circa 10% cheaper than an original factory built open top container, they may be more readily available in certain locations and at certain times, plus you can more readily get special sizes made such as 40ft high cube open tops whcih are not currently readily available elsewhere.
Specialised uses for open top shipping containers
Generally speaking we see open tops as less versatile than many other types of shipping containers for conversions or modifications.
The majority of customers want a roof on their shipping container, and as these cost more to buy than shipping containers that come with a roof their viability for a lot of customers uses are limited.
The most popular use for open top containers remains for the shipment of over height cargo or cargo that wants to be loaded via crane.
We have seen projects where people will sink open top containers, load then with ballast and then use then as a temporary or permanent barrier. We have also seen them used to secure and store plant and machinery that may be too tall to go inside a standard shipping container.
They are generally not suitable for use as a large skip, water tank or similar, the side walls do not have suitable strength in them to take serious weights pressing against the sides without heavy reinforcement.
Where to buy open top shipping containers
Of course with the UKs biggest online range of shipping containers then look no further! We have regular stocks of shipping containers in our network of depots across the UK, and we also have options to source in large volumes or original open tops, and to manufacture large volumes of modified open tops as required.
With the knowledge and the supply, please feel free to contact us and we will be more than happy to help with your open top shipping container requirements.