Section 6 Umbilicals Composed of Multi-Size Hoses and Electrical Cables

6.1.1 Umbilical should be suitable for external temperatures between minus 40°C and +60°C.

6.1.2 Umbilical of hoses tested in accordance with section 5 and electric cables complying with Pt 6 Electrical Installations and Control Engineering Systems are to be held together by sheathing or braiding.

6.1.3 In the case of sheathed umbilical provision is to be made for the escape of gas to avoid rupture of the sheathing in the event of a leaking hose.

6.1.4 Consideration should be given to the helix angle of wound components and this is to be agreed with the manufacturer.

6.1.5 The length of the umbilical if separated from hoisting rope is at least to allow an excursion of the bell to maximum diving depth plus 5 per cent, or actual bottom plus 5 per cent, whichever is greater.

6.1.6 The termination points when the umbilical enters connectors and penetrators are not to be subject to external loads or moments.

6.1.7 The ultimate tensile strength of the umbilical is not to be less than the twice the maximum load expected during normal and emergency operations.

6.2.1 The arrangement of individual hoses and electric cables between the termination of the umbilical and connections to the submerged submersible or diving bell are to be such that under normal operating conditions the hoses and cables are not subjected to any load.

6.2.2 The lifting line, or other strength member, if incorporated into the umbilical, is to be tested in accordance with the National Codes of Practice as applicable.

6.2.4 For additional design requirements for hose and umbilicals refer to Pt 5, Ch 5, 8 Additional Design Requirements.

6.3.1 A sample is to be cut from a completed umbilical, or a sample made up in an identical manner, of a length at least 44 times the average diameter. The sample is to include any strength member or coupling/ joint and is to be bent through 1800 on a pulley having a diameter to accommodate the minimum recommended static bend radius as agreed with the manufacturer, provided that the resultant diameter is not less than 13 times the average diameter of the umbilical. The sample is to be cycled 3000 times at the design load, taken as 25 per cent of the break load. During the test and upon completion, the sample is to be examined for signs of damage likely to degrade the design specification (e.g., electrical continuity, physical damage, etc.). If a strength member is incorporated, the sample is to be attached to the pulley machine by that member and, where possible, using the same method of termination as that employed in service. The width of the pulley groove is to be not less than five per cent greater than the outside diameter of the umbilical. See also Figure 5.6.1 Cycle Test.

Figure 5.6.1 Cycle Test

6.3.2 Where it is intended that an umbilical is to be used in areas where it may be subjected to air temperatures above 32°C or below 0°C, then the test in Pt 5, Ch 5, 6.3 Testing (of composite umbilicals) 6.3.1 is to be carried out at the anticipated maximum or minimum temperature. The manufacturers proposals are to be taken into account.

6.3.3 All hoses in completed umbilicals are to be hydrostatically pressurized simultaneously to 1,5 times the system working pressure and held for sufficient time for all electrical cables to be tested to their design specification.