Anatomy of a Shipping Container

16. 5. 2025

Welcome to the most comprehensive dictionary page that reveals every detail of shipping container anatomy. This page is intended not only for logistics specialists, manufacturers and sellers, but also for anyone planning to buy a shipping container, modify it, or is interested in the technical aspects of global transport. In each section you will find expanded, practical and technical information based on the latest world and Czech sources, including specific standards and material specifications.

Basic Frame Structure – Container Skeleton

The frame forms the backbone of the container and ensures its load-bearing capacity even at maximum load. It is a highly precise steel structure whose individual elements are designed and manufactured according to strict international standards (in particular ISO).

Corner Castings

ParameterValue/Description
StandardISO 1161
MaterialCast steel, e.g. ASTM A27 Grade 70-36
Dimensions178 mm × 162 mm × 118 mm
Number per container8
Openings3 on each corner casting
FasteningWelding
Quality controlISO 1161 certification, strength tests

Main roles:

  • Lifting and handling: Openings are precisely calibrated for spreaders, cranes and clamping mechanisms.
  • Stacking: All weight of stacked containers is transferred through corner castings and posts – the roof is NOT load-bearing.
  • Fastening: Twist locks secure safe connection between containers and with transport vehicles.

Technical highlights:

  • Corner castings are milled with millimeter precision, which is essential for global compatibility.
  • Cast steel is preferred due to extreme strength, weldability and resistance to long-term stress.
  • Welding is the only recommended fastening method – only this guarantees connection integrity.

Corner Posts

  • Material: High-strength steel, thickness up to 10 mm
  • Function: Transfer vertical forces; their strength is essential for stacking safety
  • Control: Repairs and replacements always according to IICL standard to ensure structural safety

Top and Bottom Rails and Cross Members

ElementMaterialFunction
Top railSteel (e.g. Corten)Ensures longitudinal rigidity, load-bearing capacity and connection of corner posts
Bottom railSteelWeight transfer to cross members, floor support
Cross membersSteel beamsEven weight distribution of cargo, increased floor clearance
  • Cross member spacing: Usually 305 mm (12 inches) for maximum floor support
  • Advantage: Due to robust construction, there is no need to build solid foundations for container buildings

Cladding and Floor – Protective Shield

Wall and Roof Panels – Corten Steel

PropertyValue/Description
MaterialCorten steel (COR-TEN, weathering steel)
Thickness1.6–2.0 mm
Surface finishNone required; a self-healing layer forms on the surface
Service life20+ years in aggressive outdoor environment
Function of corrugated sheetsIncreases rigidity and resistance to deflection and impact
Additional infoAlso used on bridges and sculptures (e.g. Angel of the North)

Why Corten Steel?

  • Creates a stable rust layer on the surface that acts as a protective shield – the so-called “self-healing mechanism”.
  • Resists sea salt, rain and wind without need for coatings.
  • Allows long service life even under extreme stress.

Front End Wall

  • Construction: Profiled Corten sheet, firmly welded to front corner posts
  • Function: Solid barrier that prevents deformation and protects cargo during transport

Floor

MaterialDescription
Marine-grade plywood28 mm thick, laminated, impregnated against pests
AlternativeBamboo flooring – more ecological, durable
InstallationBolted to cross members
Load capacity2,000–3,000 kg/m² (depending on container type)
TreatmentInsecticides according to international shipping regulations
  • Advantage: The floor is designed to withstand repeated movement of forklifts and point loads when handling heavy goods.

Door Assembly and Identification

Cargo Doors

ElementDescription
MaterialSteel, often Corten steel
OpeningUp to 270° for maximum access
ReinforcementHorizontal and vertical for increased strength
SealingRubber around entire perimeter
Locking2× (for 20′, 40′ – 4×) locking bars

Locking Bars and Cams

  • Material: Steel
  • Function: Lock doors along entire height, ends (cams) fit into holders in the frame
  • Safety: Handles are equipped with padlock capability, often in protective box against cutting

Door Gaskets

  • Material: Rubber (EPDM, NBR)
  • Function: Ensures water-tightness, air-tightness and protection against dust and pests
  • Tightness test: Light test – no light should penetrate inside after closing

CSC Plate

NameDescription
StandardInternational Convention for Safe Containers (CSC), 1972
LocationLeft door leaf
DataManufacturer, year of manufacture, maximum gross weight, stacking weight, date of next inspection or ACEP program
  • Without a valid CSC plate, the container is not suitable for international transport.
  • ACEP: Continuous inspection and maintenance program that allows operation without the need for regular periodic inspections.

Special and Supplementary Elements

Forklift Pockets

  • Use: Allow handling of empty container with forklift
  • Standard: Common for 20′ containers, less frequent for 40′ due to safety and weight
  • Dimensions: Standard 362 mm (width) × 115 mm (height), spacing 2,050 mm

Twist Locks

  • Function: Mechanical connection of containers to each other and to chassis/wagon/ship
  • Use: 90° rotation secures locking in corner casting

Gooseneck Tunnel

  • Location: In the middle of the floor at the front end of 40′ containers
  • Function: Allows seating on special “gooseneck” chassis and reduces overall height of the unit

Ventilators

Materials and International Standards

Most Common Materials

ElementMaterial
Frame, walls, roofCorten steel (COR-TEN)
Corner castingsCast steel (ASTM A27 etc.)
FloorWater-resistant plywood, bamboo
SealingRubber (EPDM, NBR)

Main International Standards

StandardDescription
ISO 1161Corner castings – dimensions, strength, quality control
ISO 668Basic dimensions and container classification
ISO 1496Technical requirements for construction and testing
CSC (1972)Safety standards for construction and maintenance
Customs Convention (1972)Simplification of customs procedures for containers


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