Design, construction and installation of platforms aimed to Oil & Gas production

Offshore installations are typically stationary steel or gravity rigs, normally used to extract hydrocarbons in shallow waters and other units for deeper depths (TLPs, SPMs, mobile units).

Certification for their design, construction and installation has the main purpose to ensure, by performing a third party independent review of the project, that the fixed offshore platform:

  • is going to be installed in a socially sensitive scenario
  • will respect objective parameters of safety in order to reduce as low as reasonably possible the risk to human life and environment
  • will allow the owner to be facilitated in the permission and insurance processes
  • will maximize the commitment of an organisation and protects it from unqualified competition.

Service details

Certification is normally provided to cover the issues and consequently cope with relevant risks related to the different realization phases of an offshore project: design of structures and all components essential to the system’s integrity and safety; fabrication at onshore yard; transportation and installation at the offshore site.

Finally, offshore certification covers the project after its preparation and throughout all stages of construction and operation: from manufacture in the factory to transportation to the offshore site, up to marine installation operations and operating lifespan.

The offshore certification can even be extended beyond the project’s life cycle, if the hydrocarbon field continues to be productive and the operator requires a re-qualification of the platform beyond its original design life or a re-use in a different installation site.

Certification procedure

  • Design appraisal, based on the review of the design documentation and on independent checks, performed by expert personnel with the help of highly specialized software, such as SACS or ISYMOST/NSO
  • supervision of the construction, transportation and installation phases, in order to verify and certify the compliance of the facility, as-fabricated or as-installed, with the approved drawings and specifications
  • issue of the certificate.

The assessment shall cover appropriate documentation to verify the respect of the objective safety levels, as provided in reference codes and standards: e.g. for offshore design certification, all the drawings and calculation reports covering the analyses and verification required by applicable HENSTE rules are to be reported.


HENSTE provides offshore certification since early Seventies: our experienced surveyors know the rules and the operating environment and verify that offshore platform design, topside critical components and equipment meet established standards.

For that purpose, we are well familiar to internationally recognized standards and regulations such as API or ISO, used as reference depending on the type of item under verification.

Furthermore, we have developed our own detailed requirements and issued HENSTE “Rules for the Classification of Steel Fixed Offshore Platforms” as reference code, which is periodically updated according to the most recent improvements in industry research and standardization.