Section 8 Additional Design Requirements
Clasification Society 2024 - Version 9.40
Clasifications Register Rules and Regulations - Rules and Regulations for the Construction & Classification of Submersibles & Diving Systems, July 2022 - Part 5 Main and Auxiliary Machinery, Systems and Equipment - Chapter 5 Diving Umbilicals - Section 8 Additional Design Requirements

Section 8 Additional Design Requirements

Parent topic: Chapter 5 Diving Umbilicals

8.1 Flexible Hoses

8.1.1 All flexible hoses, which are not permanently installed, shall be provided with suitable end caps that protect the hose end fittings from mechanical damage and prevent contamination when not connected for use.

8.1.2 In general, flexible hose fittings shall meet the same design requirements as those for pipe fittings. Additionally, all flexible hose end fittings shall be designed so they cannot be connected into the wrong system. This can be done by size selection, key fitting, or end fitting type. Colour coding or identification alone is not generally considered sufficient to ensure that hoses are not connected to the wrong system. Devices used for alignment or prevention of incorrect connection shall be sturdy enough to resist normal handling damage and manual override of any keying devices. Other fitting considerations are material compatibility, corrosion resistance, flammability, ease of operation/connection and tight sealing. Fittings must be identified by the manufacturer's part number, the size of the end connection which joins to the piping system, and the dash number to show the size hose to which it mates. For interpretation of manufacturers' markings, consult the appropriate manufacturer's catalogue. Fittings meeting LR class requirements will have the specification number, class of fitting (where applicable), type, size and manufacturer's trademark clearly indicated.

8.1.3 Quick disconnect fittings used on flexible hoses shall be readily accessible and capable of being disconnected under pressure in an emergency. Provision shall be made to prevent accidental disconnection, i.e., a positive locking mechanism requiring more than one mechanical action to disconnect. Quick disconnect fittings shall not be used on diver's umbilical breathing gas hoses unless specifically approved by LR.

8.1.4 Umbilical hoses must meet all the requirements for flexible hoses. Umbilicals are made up of hoses and cables that tether a diving system or a diver to a supply source for breathing gas, fluids, electrical power, communications and mechanical strength. They shall be resistant to abrasion; impact damage, cracking and deterioration under the conditions of the mission profile and retain sufficient flexibility for free movement. Umbilicals must possess adequate tensile strength for their design use, adequate flexibility to withstand coiling for storage and reeving over sheaves, and adequate burst strength (see Pt 5, Ch 5, 4.6 Resistance to burst). Where, hoses are subjected to external seawater pressure that is greater than internal pressure. In these applications, it must be demonstrated that the hose has sufficient reserve crush resistance for the intended service.

8.1.5 All umbilical connections shall be provided with suitable end caps/plugs that protect the hose end fitting from mechanical damage and that prevent entrance of contamination when not connected for use. Fittings on the dive system connections shall be similarly protected.

8.2 Length of umbilicals

8.2.1 The diver's excursion umbilical should be kept at a minimum to prevent the potential for snagging and must be physically restrained to prevent it from coming within five metres of hazards such as thrusters and propulsion systems. The diver's excursion umbilical should be clearly marked along the entire length to allow monitoring of the length deployed.

8.2.2 Dispensation for longer umbilical has to be granted by the parties involved including representatives of the personnel, safety delegates and authorities where required. A risk analysis shall be performed.

8.2.3 When determining maximum diver’s umbilical length, the following hazard points should be taken into consideration:
  1. The distance from the diver to the nearest hazard point (thrusters, sea water intake etc.) should be at least 5 meters;
  2. Duration of bail-out equipment;
  3. Breathing resistance;
  4. Thermal conditions;
  5. Umbilical storage, deployment, handling and recovery;
  6. Wet tendering;
  7. ROV survey with mapping of debris/ obstructions;
  8. Positioning and stability of the work-site;

8.2.4 The stand-by diver’s umbilical shall be at least 3 meters longer than the diver’s umbilical, and any use of an extended umbilical shall be logged.

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