DNV 2.7-1: An Internationally Authoritative Standard for Offshore Containers

DNV 2.7-1 is an internationally authoritative standard formulated by Det Norske Veritas (DNV) specifically for offshore containers. It was created to fill the industry gap where early international and various standards failed to cover offshore containers. First released in May 1989, it retained core strength and design requirements after a revision in 1995, and underwent a comprehensive update in 2006 with supplementary detailed clauses. To date, it remains the core basis for the manufacturing and certification of offshore containers. Below is an introduction to its key information:

Core Scope of Application

This standard covers all types of containers used for maritime transportation, including cargo containers, special service containers, waste collection skips, and more. It applies not only to general offshore containers but also imposes basic constraints on offshore tank containers carrying dangerous goods. In addition to complying with this standard, such tank containers must also obtain additional certification in accordance with the IMDG Code. Its design requirements encompass three critical transportation phases: container delivery to shore, on-board transportation, and lifting operations at offshore installations.

Key Technical and Quality Requirements

Materials

It explicitly stipulates that the steel used for the main structure shall be carbon steel, carbon-manganese steel, or equivalent grades. These materials must pass the Charpy impact test to prevent brittle fracture. Materials such as austenitic stainless steel shall also comply with the corresponding European standards or DNV ship classification regulations.

Design

Detailed requirements are specified for structural strength, anti-overturning stability, lifting point welding, stacking devices, and other components of the containers. It even includes special clauses such as upper protection for open-top containers and fork-lift testing for elongated containers.

Production

New detailed requirements for Non-Destructive Examination (NDE) have been added, and the production testing process has been optimized. Meanwhile, the calculation methods, certification requirements, and marking specifications for lifting slings have been significantly revised.

Correlation with Other Standards

The requirements for the design, testing, and production of offshore containers specified in the European standard EN 12079 are directly based on DNV 2.7-1. After the 2006 revision, some requirements of this standard were adjusted to align with the updated EN 12079. Additionally, containers certified under this standard can meet the relevant requirements of the IMO Circular MSC/Circ.860 without the need for redundant re-certification.

Core Certification Process

The certification process is highly targeted, consisting of three key steps:

Comprehensive Design Evaluation

A full assessment is conducted on design details such as container dimensions, rated load capacity, and welding methods.

Production Process Audit

In-process inspections are carried out during the manufacturing phase to ensure compliance with specifications.

Final Prototype Inspection

Certification is only granted after the prototype product passes the final inspection.

Containers previously certified under the old version of the standard do not require re-certification. However, the lifting sling shackles and chains of some containers must meet the higher requirements specified in the updated standard.