Have you ever noticed the letters "ISO" on shipping containers and wondered what they mean? Let's take a closer look at what ISO containers are and why they matter in global trade.

In essence, ISO containers are standardised, reusable steel boxes used to transport goods around the world. Their design means that they can be moved efficiently between ships, trains, and lorries – hence the term "intermodal". But there's much more to these common steel boxes than meets the eye.

What ISO Stands For

ISO stands for the International Organisation for Standardisation. This independent, non-governmental organisation, founded in 1947, develops international standards to ensure the quality, safety, and efficiency of products, services, and systems. The name "ISO" isn't an abbreviation; it's derived from the Greek word "isos," meaning "equal". This reflects the organisation's goal of creating uniform standards across different languages and countries.

The History of ISO Containers

Before ISO containers were introduced, transporting goods was chaotic and inefficient. Cargo came in various shapes and sizes, making loading and unloading a time-consuming and costly process. The journey towards standardised shipping containers began in the early 20th century, with initial efforts focused on containers for coal transportation in England. However, it wasn't until the mid-1950s that the modern ISO container took shape.

American trucker Malcom McLean, recognising the need for a more efficient system, developed and patented the first ISO container in 1956. His design, featuring a sturdy steel structure and reinforced corners for stacking, completely revolutionised cargo transportation. McLean's company, Sea-Land Shipping, pioneered the use of these containers, and their popularity soared during the Vietnam War when the US military utilised them to transport supplies quickly and efficiently.

By the late 1960s, with the introduction of ISO 668, the dimensions of shipping containers were standardised internationally. This global standardisation paved the way for the seamless intermodal transportation we see today, and it led to the development of further standards to ensure the safe and efficient use of ISO containers worldwide.

ISO Standards

The International Organisation for Standardisation (ISO) plays a vital role in ensuring the safety, reliability, and interoperability of ISO containers. These standards cover various aspects, including the following:

Dimensions and Tolerances

ISO 6346 specifies the dimensions, tolerances, and identification markings for freight containers. This ensures that containers can be efficiently stacked and transported across different modes of transport. The most common lengths are 20ft and 40ft, but other lengths, such as 24ft, 28ft, 45ft, 48ft, and 53ft, also exist .

Structural Integrity

ISO standards define the structural requirements for containers, ensuring they can withstand the stresses of transportation and handling. This includes specifications for the strength of the steel, the design of the corner posts, and the construction of the doors.

Safety Features

ISO standards address safety features such as locking mechanisms, ventilation systems, and markings for hazardous materials. This helps to protect cargo and ensure the safety of those handling the containers.

Convention for Safe Containers (CSC)

The Convention for Safe Containers (CSC) is an international agreement that sets safety standards for shipping containers . Each ISO container is equipped with a CSC plate that provides an international code system to identify the specifics of each particular container. This plate contains information such as the container's manufacturer, date of manufacture, and maximum gross weight.

Learn more about CSC plating.

ISO Member Categories

ISO membership is made up of national standards bodies from different countries, divided into three categories based on their level of participation:

• Full members: These are national standards bodies that actively participate in ISO’s work. They have voting rights and help shape international standards.
• Correspondent members: These are organisations from countries that do not have a fully developed national standards system. They can observe ISO’s work and receive updates but cannot vote.
• Subscriber members: These are typically from smaller or developing countries with limited involvement in ISO. They follow ISO’s activities but do not actively participate in the standard-setting process.

ISO Benefits

The standardisation of ISO containers has brought numerous benefits to the shipping industry and the global economy:

• Reduced shipping costs: Standardised dimensions allow for efficient stacking and handling, maximising space utilisation on ships and reducing transportation costs.
• Increased efficiency: Seamless transfer between different modes of transport eliminates the need for repackaging, speeding up delivery times and reducing handling costs.
• Improved safety: Robust construction and standardised safety features enhance the safety of cargo and those involved in their transportation.
• Enhanced security: Secure locking mechanisms and standardised markings help to prevent theft and tampering.
• Environmental benefits: Reusable containers and reduced transportation distances contribute to a lower environmental footprint.

ISO Features

ISO containers offer several key features that contribute to their strength, durability, and versatility:

• Steel construction: Corten steel, known for its strength and corrosion resistance, is the primary material used in ISO container construction. To combat corrosion, manufacturers apply a multi-step treatment process that includes sandblasting, a zinc-rich epoxy primer, and high-quality marine-grade paint.  
• Corrugated walls: The corrugated design of the container walls enhances their strength and rigidity, allowing them to withstand heavy loads and harsh conditions.
• Reinforced corners: Corner posts are reinforced to withstand the forces of stacking and lifting, ensuring the structural integrity of the container.  
• Secure doors: Heavy-duty steel doors, typically 2 inches thick, with robust locking mechanisms provide security and protection against the elements. These doors feature vertical corrugations for added strength and industrial-grade rubber seals along all four edges to create a watertight and airtight environment inside the container.
• Locking mechanisms: ISO containers utilise sophisticated locking systems to ensure the security of the cargo. Most containers include at least two locking bars per door, while high-security models may incorporate up to four. These locking bars engage with cam keepers to prevent racking, and the door handle rotates the lock bar to initiate the door opening process.
• Floor construction: ISO containers typically feature marine-grade plywood flooring with a thickness of 1.12 inches, chosen for its durability and resistance to moisture. This plywood is specifically designed for heavy-duty operations and offers long-running durability and faultless moisture resistance.  
• Ventilation: Ventilation openings allow for airflow, preventing condensation and protecting cargo from moisture damage. 

ISO Types

While the standard ISO container is a rectangular steel box, there are various specialised types designed for specific cargo needs.

• Shipping containers: The most common type, used for transporting dry goods that don’t require temperature control.
• Refrigerated containers (Reefers): Have built-in refrigeration units to maintain specific temperatures for perishable goods. 
• Open-top containers: Have a removable roof, allowing for the loading of oversized cargo from the top.
• Flat rack containers: Have collapsible sides, making them suitable for transporting large or oddly shaped items.
• Offshore containers: Designed for use in the offshore oil and gas industry, these containers are built to withstand harsh sea conditions and are often used to transport equipment and supplies to and from offshore platforms.
• Multi-door containers: Feature multiple doors along their sides, facilitating easier access to specific sections of the container without unloading the entire contents.
• Open side containers: Similar to standard containers but with doors that open on the sides, providing a wider space for loading and unloading goods.
• Tunnel containers: Also known as double-door containers, they have doors at both ends, resembling a tunnel when both are open, which aids in quick loading and unloading.

Willbox supplies a wide range of container solutions to meet diverse shipping and site storage and accommodation needs.

Customising ISO Containers

While standard ISO containers serve most shipping needs, customisation options exist for specialised cargo. Some modifications include:  

• Insulation for shipping temperature-sensitive goods.
• Additional tie-down points for heavy or oddly shaped items.
• Custom flooring materials (e.g., steel for extra durability).
• Interior lighting systems for improved visibility during loading/unloading.  

Unique Applications of ISO Containers

The versatility of ISO containers extends far beyond their traditional use in shipping. Their adaptability has led to a wide range of unique applications, including:

• Tiny homes: For those looking to downsize and live minimally, a shipping container can make an affordable housing option.  
• Temporary housing: ISO containers can be used to provide temporary accommodation in disaster relief situations or for construction workers on remote sites.  
• Press boxes: ISO containers can be used as press boxes at sporting events or other outdoor gatherings, providing shelter and a vantage point for the media.
• Cafes or food trucks: With some modifications, ISO containers can be transformed into cafes or food trucks, offering a unique and mobile space for selling food and beverages.  
• Medical clinics: In the event of a natural disaster or other emergency, ISO containers provide a portable and cost-efficient way to set up a medical clinic .  
• Training facilities: ISO containers can be used as training facilities for emergency responders and the military, offering a safe and controlled environment for simulations and exercises.
• Schools: In locations where communities can't afford to build traditional schools, containers may be converted into classrooms, providing a cost-effective solution for education.
• Sports stands - Shipping containers can be converted into modular sporting stands, providing covered seating for spectators at sports events. These structures are durable, weather-resistant, and can be customised to accommodate various capacities.
• Ticket offices - Modified shipping containers can serve as ticket booths for events, offering secure and functional spaces for staff to manage ticket sales. These container-based ticket offices are portable, can be equipped with necessary amenities, and provide a professional appearance.

These diverse applications highlight the adaptability and versatility of ISO containers, making them a valuable asset in various industries and situations.

Conclusion

ISO containers have transformed global trade by providing a safe, efficient, and cost-effective way to transport goods. Their standardised design, durability, and versatility make them essential to the modern supply chain, ensuring smooth movement of everything from food to clothing.

By simplifying international logistics and reducing trade barriers, ISO containers have fueled global commerce and economic growth. Their adaptability extends beyond shipping, proving valuable in various industries and applications.

Willbox For All Your Container Needs

Looking for high-quality shipping containers for sale or hire? With 23 depots nationwide, Willbox is a leading UK supplier, offering a wide range of ISO containers to meet your transportation, storage and site accommodation needs. 

Whether you need standard shipping containers, refrigerated units, specialised containers for transportation or a bespoke conversion, contact our expert team who will be happy to help.