GB/T 10541-2023Rubber hose, oil suction and discharge, offshore mooring (English PDF)

4.1 Classification

4.1.1

Classification by external shape:

a) submarine hose with or without positioning collars (the bores at the two ends may differ);

b) submarine hose with special reinforced ends;

c) floating hose (the bores at the two ends may differ);

d) partially floating hose with special reinforced ends;

e) tanker rail hose.

4.1.2

Classification by construction:

a) single-carcass hose: a hose containing only the main carcass reinforcement;

b) double-carcass hose: a hose which, in addition to the main carcass reinforcement, has the reinforcement of a second, secondary carcass.

Note: there is a space between the main carcass and the secondary carcass to contain any liquid escaping from the main carcass through slow leakage or sudden failure.

4.2 Construction

4.2.1

The hose consists of a lining, reinforcement, a cover and flange connectors. As required, it may have special reinforcement, electrical bonding wires, buoyancy material and a buffer layer. The construction of the hose is shown in Figure 1.

Figure 1 - Schematic diagram of hose construction. Key: 1 flange connector; 2 electrical bonding wire; 3 lining; 4 main carcass reinforcement; 5 metal helix; 6 special reinforcement; 7 buffer layer; 8 lining of the secondary carcass; 9 reinforcement of the secondary carcass; 10 cover of the submarine hose; 11 buoyancy material; 12 cover of the floating hose.

4.2.2

The lining consists of an oil-resistant and low-temperature-resistant rubber material.

4.2.3

The reinforcement comprises the following structures:

a) textile cord fabric or steel cord fabric reinforcement plies;

b) metal helix or rings embedded in the compound, or other similar types of reinforcement;

c) special reinforcement, which may be used in combination with a), b) or with a) and b).

4.2.4

The cover consists of an outermost layer of material such as rubber, polyurea or polyurethane, and includes at least two rubberised textile reinforcement plies.

4.2.5

The flange connector consists of a connector made of steel pipe and retaining rings, and a flange.

5.1 Materials

5.1.1 Lining

The properties of the lining compound of the hose shall meet the following requirements:

a) liquid resistance of the lining compound (volume swell): when tested in accordance with GB/T 1690, after immersion in liquid C at 40 °C for 48 h, the volume swell shall not exceed 60%;

b) low-temperature resistance of the lining compound: when tested in accordance with GB/T 6036, no severe deformation at -20 °C;

c) the physical and mechanical properties of the lining compound shall meet the requirements of Table 1.

Table 1 - Physical and mechanical properties of materials (lining; rubber cover; polyurea cover; polyurethane cover; test method): tensile strength, MPa: >= 13; >= 12; >= 15; >= 12. Elongation at break, %: >= 450; >= 350; >= 300; >= 300. Test method for both: GB/T 528-2009, type 1 test piece.

5.1.2 Cover

The properties of the cover material of the hose shall meet the following requirements:

a) abrasion resistance of the cover material: when tested in accordance with method A of GB/T 9867-2008, using standard reference compound No. 1, the volume loss shall not exceed 250 mm3;

b) ozone resistance of the cover material: when tested in accordance with GB/T 7762 at an ozone concentration of (50 ± 5) × 10^-8, a temperature of (40 ± 2) °C, a relative humidity of 65% and an elongation of (10 ± 1)% for 72 h, no cracking shall be observed under 2x magnification;

c) low-temperature resistance of the cover material: when tested in accordance with GB/T 6036, no severe deformation at -29 °C;

d) the physical and mechanical properties of the cover material shall meet the requirements of Table 1.

5.1.3 Flange connectors

5.1.3.1 Connector

Seamless or double submerged arc welded steel pipe used to manufacture the connector shall be killed or semi-killed steel with a carbon content of 0.23% meeting the requirements of grade A or grade B of ASTM A106/A106M-18 or grade A or grade B of GB/T 9711-2017, and shall have standard weight. The connector may also be made of steel plate meeting the requirements of grade C of ASTM A285/A285M-17; all welds shall be 100% radiographically examined in accordance with BS EN 1435. The welds shall meet the requirements of UW 51B of ASME VIII-1-2013.

The retaining rings welded on the connector to anchor the reinforcement shall be of killed or semi-killed steel meeting the requirements of grade C of ASTM A285/A285M-17 with a maximum carbon content of 0.23%, and the welds shall be examined by magnetic particle testing in accordance with Appendix 6 of ASME VIII-1-2013.

5.1.3.2 Flange

The flange material shall be forged steel flanges meeting the requirements of GB/T 12228 or an equivalent standard, with a maximum carbon content of 0.25%. The circumferential welds between the flange and the connector shall be 100% radiographically examined in accordance with BS EN 1435. The welds shall meet the requirements of UW 51B of ASME VIII-1-2013.

5.1.3.3 Coating

The exposed inner and outer surfaces of the flange and the steel pipe shall be protected by hot-dip galvanising, with a zinc coating mass of at least 610 g/m2, i.e. a minimum thickness of 85 µm.

Note: other methods of protecting the exposed surfaces are also acceptable.

5.1.3.4 Lifting lugs

Lifting lugs shall be welded at the flanges at both ends of the tanker rail hose; they shall be made of carbon steel with a maximum carbon content of 0.23%. Normally, the tanker end of each hose is fitted with 4 lifting lugs spaced at 90°, and the other end with 2 lugs spaced at 180°, with the lugs of the two end flanges in line. If the purchaser has special requirements, 2 lugs may be fitted at each end, with the lugs of the two end flanges in line.

The lifting lugs shall pass a proof load equal to 2.5 times the safe working load. Each lug is subjected to the proof load twice, once perpendicular to the hose axis and once parallel to it. The load is applied for not less than 2 min, and the lugs, metal fittings and flanges shall show no damage or permanent deformation. After the proof load test, the welds shall be 100% examined by magnetic particle testing in accordance with Appendix 6 of ASME VIII-1-2013. The test loads and minimum breaking loads of the lifting lugs shall meet Table 2.

Table 2 - Test loads of lifting lugs (hose bore, mm: safe working load, kN; proof load, kN; minimum breaking load, kN):

150: 40; 100; 200.

200: 50; 125; 250.

250: 70; 175; 350.

300: 100; 250; 500.

400: 150; 375; 750.

500: 200; 500; 1 000.

600: 200; 500; 1 000.

5.2 Appearance

5.2.1

The lining of the hose shall have no obvious grooves and shall be free from defects such as blisters, delamination and cracks.

5.2.2

The cover of the hose shall be smooth, without obvious bulges or depressions, and free from defects such as blisters, delamination and cracks.

5.3 Length and tolerance

The length between the end faces of the flanges at the two ends is measured as specified in GB/T 9573; there are normally three standard lengths, 9.1 m, 10.7 m and 12.2 m. The length tolerance shall not be greater than +1% or less than -1%.

5.4 Bolt hole alignment

The alignment of the flange bolt holes at the two ends of the hose is measured with an infrared level; the holes shall be in a straight line, with a tolerance of one hole diameter.

5.5 Installation distance

The installation distance is the straight-line length between the bolt holes on the back face of the flange and the hose body; see Figure 2. The installation distance shall meet the requirements of Table 3.

Figure 2 - Schematic diagram of the installation distance. Key: l installation distance; 1 flange; 2 hose body.