“DNV Certified” is a word used frequently in the offshore oil and gas business.
When researching and/or purchasing a DNV 2.7-1 offshore reefer container, it can get very technical in understanding what you should be looking for.
Because of how technical it is, we wanted to prepare this article to help you understand more about DNV 2.7-1 offshore reefer containers.
We will be covering the common questions asked about DNV 2.7-1 offshore reefer containers below:
- What does DNV Certified mean?
- What is a DNV 2.7-1 Offshore Reefer Container?
- What are the 3 main categories of offshore containers?
- What is the difference between DNV 2.7-1 and DNV 2.7-3?
- Whats is the DNV 2.7-1 Standard?
- How are offshore reefers tested?
- What are the other certifications for offshore reefer containers?
What does DNV Certified mean?
DNV (Det Norske Veritas) is a Norwegian classification society that joined with Germanischer Lloyd (GL) in September 2013 to form the DNV GL Group, the world’s largest classification society.
The independent name “DNV” has become somewhat obsolete after the merger, but it still exists.
DNV GL has been working to phase away from the standalone name “DNV” since 2017, but it is still widely used to this day.
What is a DNV 2.7-1 Offshore Reefer Container?
An offshore container is a mobile unit having a maximum gross mass of not more than 25000 kg that is used repeatedly in the transportation of goods or equipment across open seas, too, from, or between fixed and/or floating facilities and ships.
Besides that, these containers are used for offshore lifting that is designed for installation rather than repetitive transportation are not considered containers.
So, DNV 2.7-1 reefer containers can be used for both transportations of goods, and installation, based on your needs.
What are the Types of Offshore Containers?
There are 3 main types of offshore containers that you should know about, which are:
- Offshore freight container
- Offshore service container
- Offshore waste skip
a) Offshore freight container
Offshore freight containers are the containers built for the transport of goods.
Examples of offshore freight containers:
- General Cargo Container:
A closed container with doors
- Cargo Basket:
An open-top container for general or special cargo (e.g. pipes, risers)
- Tank Container:
A container for the transport of dangerous or non-dangerous fluids
- Bulk Container:
Container for the transport of solids in bulk
- Special Container:
Container for the transport of special cargo (e.g. garbage compactors, equipment boxes, bottle racks).
b) Offshore service container
This offshore container is built and equipped for a special service task.
These tasks are mainly temporary installations.
- power plants
- control stations
- wireline units
c) Offshore waste skip
This offshore container is used, open or closed, for the storage and removal of waste.
They are normally constructed from flat steel plates forming the container’s loadbearing sections and bracing in the form of steel profiles.
- channel or hollow sections
- being fitted horizontally around sides and ends
Waste skips may be open or have loose or hinged covers.
In addition to the pad eyes for the lifting set, these containers may also have side-mounted lugs suitable for attachment of the lifting equipment mounted on a skip lift vehicle.
What is the difference between DNV 2.7-1 and DNV 2.7-3?
We have already covered what the DNV 2.7-1 is, so we will briefly go over what the DNV 2.7-3 is.
According to DNVGL-ST-E273 Section 1.4.3, a POU (portable offshore unit) is a package or unit intended for repeated or single offshore transport and installation/lifting which may also be designed for subsea lifting.
Although the definitions may seem to be similar, it’s important to understand the primary differences.
This is especially important for design engineers as the design approach is fundamentally different between the two standards.
DNVGL-ST-E271 adheres to a “design by code” philosophy, while DNVGL-ST-E273 is a “design by analysis” approach.
Design By Code
Design by code is a fairly straightforward process.
Basically, if the offshore container falls within specified categories, then you apply the designated design criteria.
The code’s inherent structure limits the design engineer’s subjective decision-making, which results in a more streamlined review process by DNVGL.
This results in a faster and less expensive design review cycle.
Design By Analysis
Design by analysis puts more responsibility on the design engineer for defining the design basis including limits of operation, load case scenarios, and selecting and/or defining proper acceptance criteria.
Since the design engineer assumes more ownership of the design process, the engineering review phase of the certification process is more in-depth and requires a longer review cycle, and is usually more expensive than the design review for 2.7-1.
Now that we know about the approach to designing a DNV 2.7-1 offshore reefer container, what does that actually mean in terms of standardization?
What is the DNV 2.7-1 standard?
DNV 2.7-1 Standard for Certification was first published in May 1989 as “DNV Certification note 2.7-1 Offshore Freight Containers”.
It was prepared because of other regulations at the time, whether international codes, national requirements, or rules published by Det Norske Veritas (DNV).
The Standard for Certification is concerned with the certification of all types of offshore containers as transport units.
The three typical phases of transport are:
- shoreside (e.g. by forklift truck)
- by supply vessel
- lifting to and from offshore installations
The Standard for Certification includes design requirements related to all three phases.
Under conditions in which offshore containers are often transported and handled, the “normal” rate of wear and tear is high, and damage necessitating repair will occur.
However, containers designed and certified according to this Standard for Certification should have sufficient strength to withstand the normal forces encountered in offshore operations, and not suffer complete failure even if subject to more extreme loads.
Based on the standards set, how are these containers tested?
How offshore reefer containers are tested?
Offshore containers need to be tested through specific methods to ensure that they are made up to spec, and safe to use.
Both 2.7-1 and 2.7-3 are standard defining requirements and recommended practices covering the transport of offshore containers and portable offshore units.
The standards cover the specific areas of design, manufacturing, testing, certification, and periodic inspection.
Both standards cover the lifting frames of containers and, in most instances, not the equipment contained within the frames.
The requirements are defined based on safe use concerning:
- Hazard to the vessel or offshore installation
Both standards cover aspects to safe lifting and handling of these offshore containers and units between two floating vessels and between vessels and fixed or floating offshore installations.
For more information on the tests, click here to learn more.
But, besides the DNV, are there other certifications for offshore reefer containers?
What are the other certifications for offshore reefer containers?
Besides the DNV certification, there are 2 other popular certifications for offshore reefer containers.
- ISO 10855
- EN 12079
The EN ISO 10855 ‘Offshore containers and associated lifting sets’ series, is a certification adopted by CEN in 2018, which consists of three parts:
- part 1, on the design, manufacture, and marking of offshore containers
- part 2 on the design, manufacture, and marking of lifting sets
- part 3 on periodic inspection, examination, and testing.
As a whole, this series of standards describe the requirements for the design, construction, inspection, testing, and in-service examinations of offshore containers and associated lifting sets for the petroleum, petrochemical, and natural gas industry.
You can read up on a more in-depth article about the EN-ISO 10855 certification here.
The requirements for design, testing and production of offshore containers in EN 12079 are directly based on DNV Standard for Certification 2.7-1.
EN 12079 consists of three parts (identical to the ISO 10855):
- Part 1 – The design, manufacture, and marking of the offshore container
- Part 2 – The design, manufacture, and marking of the lifting sets
- Part 3 – Periodic inspection, examination, and testing of the offshore container and associated lifting set
If your offshore containers and lifting sets are certified to comply with DNV 2.7-1, then they would also comply fully with EN 12079 parts 1 and 2.
Click the linked text if you would like to know more about the EN 12079 certification
These are the common questions often asked regarding DNV 2.7-1 offshore reefer containers.
Hopefully, this article answers any of your questions about the DNV 2.7-1.
If you think we missed out on anything, or if you have a question, feel free to let us know, and we will add it to the article.