Dive System Classification

Diving systems can be built in accordance with a classification society’s own rules for diving equipment and systems, and can, at the owner’s request, be considered for class designation.  Each classification society’s rules include its own requirements for the initial design as well as periodic testing and examination of the system plant and equipment, as being in compliance with its rules.

Recently Namaka Subsea has been contacted on a few occasions by various contractors to clarify the requirements and processes of getting a diving system classed.

The objective of diving system classification is to verify the structural strength and integrity of essential parts of the diving system and its appendages, and the reliability and function of the electrical, pneumatic and hydraulic systems, power generation and those other features as well as auxiliary systems which have been built into the system in order to maintain essential services.  Classification societies aim to achieve this objective through the development and application of their own rules and by verifying compliance with international and/or national statutory regulations on behalf of flag administrations.

A diving system that has been designed and built to the appropriate rules of a society may apply for a certificate of classification from that society. However, such a certificate does not imply, and should not be construed as, a warranty of safety or fitness for purpose of the system.  It is an attestation only that the system is in compliance with the rules that have been developed and published by the society issuing the classification certificate.

It should be noted that there is a difference between a diving system being classed, built to class and certified by class.

System with Full Classification

The classification process begins with the evaluation by the classification society of a submitted design to determine its compliance with the rules for diving equipment and systems.  During construction, classification society surveyors attend the system to verify that it is built in conformance with the drawings and to the rules. On delivery, the system will receive periodic surveys by the society to verify that it is being maintained to the required standard.  These surveys generally follow a cycle of annual, intermediate and renewal surveys with the extent of the survey varying depending upon the age of the system and the type of survey being conducted.

For a system to remain ‘in class’ it must meet the class rule requirements at the completion of each survey.  Should a system sustain in-service damage, the system owner should advise the classification society so that a damage survey can be arranged.  If the surveyor decides that the damaged system no longer meets the rules, the owner must carry out repairs to bring the system back into compliance if it is to remain in class.

The same can be said with regards to any modification carried out on the system that may affect class and therefore it is imperative that a technical management of change process be in place to identify if any modifications will affect the system classification.  If it is identified that the modification will affect the system classification, then the class society should be contacted and advised of the modification.  All modification engineering, drawings, procedures, etc should all be submitted to the class society for technical review and approval so as the system class status can be maintained.

During the periodic surveys the class surveyor should have a plan to follow when carrying out the survey which may be a checklist or just references to their rules depending on the type of survey being completed.  In either way the survey scope should be agreed ahead of the survey to allow the system operating personnel to prepare for any testing requirements such as load testing, pressure testing, hyperbaric lifeboat launch, etc.  In the case of DNV-GL, a Survey Planning Document should be made available for reference as developed by the system operator and will include valuable information for the surveyor during the survey.

On completion of the survey the system classification certificate will be updated or a new one issued and an attachment to the certificate or a summary report made available, which will identify the tests carried out, the standard to which they were carried out against and any outstanding conditions of class which must be addressed in an agreed period of time.

Not all diving systems are required to be classed as this is the decision of the end user, however, in most cases saturation diving systems whether in-built or mobile systems will be awarded a class certificate on completion of the build and maintain class certification on completion of the periodic surveys stated previously.  This does not mean to say that surface orientated (air) diving systems cannot be classed, however, the process requires the diving system to be fully mobilised and the system interfaces considered before the full class certification would be awarded.

Systems Built to Classification

Diving systems can also be built to class but not be awarded class designation and follows the same process as classing a system with the exception of the final submission and technical evaluation against the class rules for the award of class certification.  This ensures that systems or equipment making up part of a system, are built to a recognised standard and can be approved by the classification society as being designed and built as per its rules.  This should not be mistaken as the system being classed as this is not the case and no class designation will be awarded.

Systems Certified by Class

In some instances, the diving system equipment may not be classed or built to class but may have been built to recognised international standards such as pressure vessel design code ASME VIII.  On completion of the build, the equipment will be commissioned and tested which can be witnessed by a classification society and the certification officially stamped by the classification society confirming that a particular test was carried out and that equipment (such as pressure vessels) have been designed and built to a specific standard successfully against a particular criterion in their presence.

Namaka Subsea

So how can Namaka assist? With decades of in-house experience of assisting with DSV, mobile saturation systems and air diving systems built, Namaka are very experienced in the processes as well as the challenges, and having worked with ALL the major  Classification Societies who have developed diving equipment and system rules are proficient with requirements. To ensure the diving systems are built in accordance with the Client requirements as well as the classification rules for the class certificate to be provided, Namaka can provide a Technical Advisor as requested by the Client to ensure that systems and processes are designed and developed to the required classification rules.

The Technical Advisor will work with the Client to ensure that processes and the design of the systems result in the overall reduction of risks associated with offshore operations and will include the evaluation of the design to be submitted to the classification society. Namaka will also interface with the classification society and equipment manufacturers during construction to verify that it is built in conformance with the drawings, processes and to the rules.

The Technical Advisor will assist the Client with the selection of equipment to ensure the equipment and supporting documentation are both fit for its intended use and comply with classification society rules. Communications between the Technical Advisor and the Client will be maintained at all times to ensure the scope of work is carried out as per Client instructions and to advise the Client of any issues that may affect the safety and efficiency of operations as well as in compliance with the classification society rules.

The basic elements of the system will be reviewed to confirm processes and procedures in place are sufficient and will include but not be limited to:

• System Design
• System Schematics/P&ID’s
• Material Traceability Documentation
• System Operating and Emergency Procedures
• System Survey Planning Document
• System Finite Element Analysis (FEA)
• System Pressure Testing
• System Commissioning
• System Support Trials (inc. test dive)
• System Certification
• System Failure Mode Effects and Criticality Analysis (FMECA)

 This may also include condition-based cost evaluation of a non-classed system if already used, which will cover an assessment of the current condition of the system as well as a scheduled evaluation identifying cost/time/resources required to carry out a scope of work to ensure the system can be re-classed and is in an operational state for safe and efficient operations. This will include the operational functionality and general condition of the equipment as well as the availability and completeness of the associated documentation and will identify a cost against each item, equipment part and the time to complete the scope of work as well as any resources required.