Section 4 Hose Approval Tests

4.1 Hydrostatic strain test

4.1.1 A sample of hose not less than 300 mm long between end fittings which has passed the ball test referred to in Pt 5, Ch 5, 5.2 Dimension, ball and hydrostatic tests 5.2.1 and with one end plugged but free, is to be tested as follows:

The pressure inside the hose is to be raised to the design pressure, held for 2 minutes and then released.
Reference marks are then to be made on the hose and their distance apart measured. These reference marks are to be not less than twice the bore of the hose from the end fittings.
The hose is to be re-pressurized to the design pressure, held for 2 minutes and while the hose is pressurized, the distance between the reference marks measured. The change in length between the reference marks is not to exceed ±3 per cent, also the change in diameter is to be limited to 3 per cent.

4.2 Pressure impulse and bend tests

4.2.1 Four samples of hose up to 19 mm bore, of length 3,5 times the minimum bend radius shown in Table 5.4.1 Bend radii between end fittings, are to be bent through 180° until the distance between the parallel end fittings is twice the minimum bend radius. Hoses of 25 mm bore, of length 400 mm between end fittings, are to be bent at the minimum bend radius through 90°.

Table 5.4.1 Bend radii

Nominal Bore Size, mm	Minimum inside bend radius of external surface, mm
3	75
5	90
6.3	100
8	110
10	125
12.5	175
16	200
19	240
25	305

4.2.2 The hose samples, prepared as per Pt 5, Ch 5, 4.2 Pressure impulse and bend tests 4.2.1, are then to be filled with water maintained at a temperature of 90°C for hoses conveying liquids and 60°C for hoses conveying gases. They are to be pressure cycled 150,000 times for liquid hoses and 50,000 times for gas hoses at a rate of not less than 1,5 cycles per second at 1,25 times the design pressure, without showing any signs of failure. The maximum rate of pressure rise is to be 7000 bar/s.

4.2.3 After undergoing the tests in Pt 5, Ch 5, 4.2 Pressure impulse and bend tests 4.2.2 the hose samples are to be destroyed.

4.3 Low temperature flexibility

4.3.1 An empty hose of minimum length 1,8 times the minimum bend radius shown in Table 5.4.1 Bend radii between end fittings, is to show no visible defect when tested in a straight condition and maintained at a temperature of — 40°C ± 2°C for a period of 3 hours and then bent through 900 at the minimum bend radius round a mandrill at the same temperature. The bend, for nominal bore size, is to be completed within the following times:

Up to and including 12,5 mm bore	5 Seconds
Over 12,5 mm — up to and including 19 mm bore	10 seconds
25 mm bore	20 seconds

On completion of the procedure in Pt 5, Ch 5, 4.3 Low temperature flexibility 4.3.1 the hose is to be maintained in the bent condition for 1 hour after reaching room temperature and then pass a hydrostatic proof pressure test of twice the design pressure in the bent condition for a period of not less than 2 minutes.

4.4 Heat test

4.4.1 No sign of visible damage or indication of failure is to occur when a 100 mm length of hose, pressurized to the design pressure is:

Held in contact with a flat plate for 15 minutes, where the temperature of the plate is to be maintained at:
1. 130°C for hoses conveying liquids, and
2. 100°C for hoses conveying gases.
For gas hoses — immersed in boiling water at atmospheric pressure for 15 minutes.

4.5 Tensile strength of hose

4.5.1 A sample of hose 1 metre long, with end fittings, is to show no sign of separation or failure when subjected to a steady pull of 1000 N for a period of 5 minutes. The hose assembly shall not leak at proof pressure.

4.6 Resistance to burst

4.6.1 A sample of hose as specified in Pt 5, Ch 5, 4.1 Hydrostatic strain test 4.1.1, with end fittings attached within the previous 30 days, is to show no sign of leakage or indication of failure below the minimum burst pressure specified below when subjected to a constant gradient hydrostatic pressure increase so as to attain the specified minimum burst pressure within a period between 15 and 30 seconds.

Burst pressures:
Evidence of the bursting pressure of each hose type is to be submitted to LR. For liquids, hoses must withstand at least 4 times, and for gases at least 5 times, the maximum permissible working pressure.

4.7 Resistance to leakage

4.7.1 A sample of hose as specified in Pt 5, Ch 5, 4.1 Hydrostatic strain test 4.1.1, with end fittings attached within the previous 30 days, is to show no sign of leakage or indication of failure after being subjected to a hydrostatic pressure of 70 per cent of the specified minimum burst pressure given in Pt 5, Ch 5, 4.6 Resistance to burst 4.6.1 for a period of 5 to 6 minutes, with the pressure then released and reapplied for a further period of 5 minutes.

4.8 External pressure test

4.8.1 Isobaric / hyperbaric systems. (For definition see Pt 1, Ch 2, 2.3 Other Definitions). A sample of hose as specified in Pt 5, Ch 5, 4.1 Hydrostatic strain test 4.1.1 with the internal pressure at atmospheric is to show no sign of collapse when subjected to an external hydrostatic pressure of 1,3 times that at the maximum design depth. With the external pressure applied proof of non-collapse is to be demonstrated by the ball test referred to in Pt 5, Ch 5, 5.2 Dimension, ball and hydrostatic tests 5.2.1. The hose sample is then to be examined to determine that:

There are no signs of permanent distortion.
There is no ingress of water into the hose, and
Tested to show that there is no sign of leakage at the end fittings when the hose is pneumatically pressurized internally to 1,5 times the design pressure.
A differential ratio of 1,5 between the internal and external pressures can be withstood without failure.

4.8.2 As an alternative to Pt 5, Ch 5, 4.8 External pressure test 4.8.1 hoses for hyperbaric systems only, may be tested as follows:

With the lower end plugged a sample of hose as specified in Pt 5, Ch 5, 4.1 Hydrostatic strain test 4.1.1 with the internal pressure at atmospheric ‘is to be subjected to an external hydrostatic pressure of 1,3 times the design pressure to cause collapse. The hose is then to be pneumatically pressurized internally to the design pressure and a steel ball, in accordance with Table 5.6.1 Ball Test, inserted in the top end and allowed to roll or drop to the plugged end to determine that the hose has recovered from any deformation. The internal pressure is then to be released and after 5 minutes, the hose re-pressurized and the ball test repeated. This procedure should be repeated 50 times ensuring that the ball strikes the fitting at the opposite end each time the hose is re-pressurized.
The hose sample is then:
1. To be examined to determine that there is no sign of damage likely to degrade the design specification of the hose.
2. To be tested to show that there is no sign of leakage at the end fittings when the hose is pneumatically pressurized internally to 1,5 times the design pressure.
3. To be hydrostatically pressurized to 75 per cent of the design burst pressure referred to in Pt 5, Ch 5, 4.6 Resistance to burst.

4.8.3 Where a hose is to be used for gas reclaim purposes or likely to operate at less than ambient pressure, a sample of hose is to be tested as indicated in Pt 5, Ch 5, 4.8 External pressure test.

4.9 Oxygen Shock Test

4.9.1 Couplings are to be oxygen shock tested when they are to be type approved for systems having an oxygen content by volume of more than 23%. A minimum of three couplings shall be tested. In case the couplings are manufactured in a wide range of sizes, where all the sizes are of same basic design, one small one medium and one of the bigger sizes shall be selected. The test is to be performed by quick opening of a ball valve producing a shock wave that moves through a copper tube into the test specimen. The test medium shall be oxygen of normal industrial grade pre-heated to +60°C. The line shall be flushed with oxygen before the test commences in order to remove as much air as possible. The pre-heater must be switched on for sufficient time ahead in order to ensure that all the oxygen has reached the required temperature before the testing starts. The test samples shall be subjected to 20 shocks of pressure increase from the atmospheric pressure to maximum design pressure.

4.9.2 The full oxygen pressure, with refill if necessary, shall act on the test samples for 10 seconds, and the time between each shock shall be 30 seconds.

Note The test is considered to be dangerous to personnel, as explosive fire may occur in the system. Strict safety precautions shall therefore be taken, and it is recommended that the test is performed in a special container without any personnel inside the container during the test.

4.9.3 A test as described in ISO 2503 or equivalent will be accepted.

4.10 Mechanical Properties

4.10.1 As proof of their mechanical properties, compact umbilicals are to be subjected to alternating bend tests and rupture tests see Pt 5, Ch 5, 4.2 Pressure impulse and bend tests. In addition, compact umbilicals are to undergo a tightness test, see Pt 5, Ch 5, 4.9 Oxygen Shock Test, in which all hoses are to be subjected simultaneously to their maximum permissible working pressure and the electrical lines are to be checked for compliance with the specified insulation and impedance values.