Tank Hydrostatic Test Procedure - FINAL

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TABLE OF CONTENTS

1. Scope (3)

2. Related documents (3)

3. Preparation of Hydrostatic Test (4)

4. Hydrostatic Test (5)

5. Cleaning and Drying (6)

6. Foundation Inspection during hydrostatic test (6)

7. Calibration of Sp here (7)

1. Scope

1.1 This procedure is applied to the hydrostatic test at field of Spherical Tanks for Saudi

Kayan Amin Project to be constructed in Al-Jubail, Saudi-Arabia.

1.2 Item to be applied

1.3 General Data of Storage Tank

2. Related documents

1) ASME Section VIII, DIV. 2, 2004 Ed & 2006 Add. :

Rules for Construction of Pressure Vessels.

2) Purchaser’s Specification

1) 000-85S-0014 : Pressure Vessels Welding, Fabrication and NDE

2) Q01-T01 : Pressure Vessels Testing and Inspection

3) Q03-E10 : Spheres Design

4) SK-Q03-F09 : Sphere-Fabrication

5) Q01-F07 : Pressure Vessels Fabrication

3. Preparation of Hydrostatic Test

3.1 Prior to the hydrostatic testing, it shall be confirmed that all specified nondestructive

examinations of welds and inspection shall have been completed with applicable codes and standards. It shall be closely checked that clips and supports shall be finished by welding on the pressure part of internal and external of tank shell as per latest approved drawing prior to water filling.

3.2 The inside of tank shall be cleaned.

3.3 The test shall be done before connecting external piping to the tank.

3.4 Before the tank is filled with test water, the points for settlement measurement shall be

marked on a tank column and the level at measurement points shall be recorded.

3.5 The test equipment shall be prepared as shown in Fig. 1.

3.6 At least, two pressure gauges shall be installed and one of them shall be placed at the top

of the tank and also one pressure recorder shall be installed at the bottom of tank.

Hydrostatic test continuous recording time/pressure graph shall be provided throughout the testing cycle.

3.7 The pressure gauge used in the testing shall be calibrated against a standard deadweight

tester or a calibrated master gauge at least every 6 months. And dial indicating pressure gauge shall be graduated over a range of about double the intended maximum test pressure, but in no case, the range shall be less than 1 1/2 nor more than 4 times that pressure.

3.8 Before test water is introduced to the tank, the cover of roof manholes shall be opened. 3.9 For the safety, the tank shall be bounded with ropes and warning sign during the test

3.10 Hydrostatic tests shall be carried out using the type of gaskets which be used in service. 3.11 Hydrostatic test water shall be controlled chloride contents less than 40ppm.

4. Hydrostatic Test

※ During holding, settlement check shall be carried out and measurement time and holding period will be decided by considering actual settlement of tank.

Note:

T.P: Test Pressure

D.P: Design Pressure

4.1. After the tank is completed but before any permanent external piping is connected to the

tank, the tank shall be tested according to the following methods.

4.2. Before start to test, the test equipment shall be inspected to see that all low-pressure

fitting lines and appurtenances is tight and should not be subjected to the test pressure, and shall be disconnected or isolated by valves or other suitable means.

4.3. The tank may be half-filled with test water as quickly as practicable, having regard to size,

the pumping facilities and water supply available.

4.4. The water filling rate introduced into a tank shall not exceed 3 feet( 0.9 m) of depth per

hour.

4.5. During filling water to the tank, the vent in top of the tank shall be opened to the

Rate of water filling = 3 feet of depth per hour. (Vol.) (Time)

Water Filling (Time)

Pressurizing

atmosphere to prevent accumulation of pressure.

4.6. The temperature of the water used in the tests should be not less than 17o C.

4.7. Further filling shall not proceed until levels have been taken and checked against the

readings taken when empty to ensure that no uneven settlement is occurring. After acceptance of settlement, next step for water filling can proceed until the tank is three-quarters full, and then level readings shall be taken again.

4.8. Provided the tank remains level only slight settlement due to load, filling can proceed until

the tanks is filled with test water to the full filling.

4.9. The tank shall be inspected frequently during the water filling, and settlement shall be

checked at every holding stage.

4.10. After 24 hour holding of water in full of water, the pressure shall be increased with the

rate of maximum 0.1x design pressure per 5 minute. (as per approved drawing regarding test pressure).

4.11. During the increase of pressure, it shall be prohibited to enter the test area.

4.12. When the pressure is reached to test pressure, the pressure shall be hold for minimum

60 minutes, and then reduce the pressure to design pressure.

4.13. At the design pressure, all welds seam shall be visually checked. If any leakage is not

appeared on the welds and connection, the hydrotest is accepted.

4.14. After accept of Hydrotest, the pressure shall be reduced gradually to the atmosphere.

And then start to drain the test water. Before test water is drained out, the cover of roof manhole shall be opened.

4.1

5. After completion of Hydrotest, any standing water, silt or drift left in the tank shall be

cleaned out with broom.

5. Cleaning and Drying

After completion of Hydrotest, any standing water, silt or drift left in the tank shall be cleaned out with water jet and broom, and then dry the inside of tank by blowing the air. N2 gas purge with double valve and gauging shall be done at the pressure maintaining 100KPa. (Refer to the attached schematic diagram of N2 purge).

6. Foundation Inspection during hydrostatic test

During water filling, every foundation of lower column of the tank shall be checked. Differential settlement or uneven settlement requires an immediate stop to water filling. Any further filling with water will depend on an evaluation of the measured settlement.

6.1 The settlement of foundation under each column shall be checked at the following times.

1) Before filling test water

2) When the half, 3/4 and full volume of the tank is filled with water

3) After holding of full filling

4) After drainage of test water (Empty)

6.2 The settlement of the tank foundation shall not exceed allowable tolerances. The

allowable tolerance shall be decided from civil design. But as a minimum requirement, the permissible settlement of tank foundation shall be not more than the values as shown below. But the values as shown below shall be clarified by civil design.

1)

Even settlement (W1)

:

100 mm

2)

Tilt of tank foundation (W2) : 1 / 250

3) Deviation among measurements (W3) :

< 50 mm

7. Calibration of Sphere

The tank calibration shall be carried out after hydrostatic test to verify the volume of

tank, the procedure shall be approved by owner. Calibration method will be

submitted before calibration separately.

SKETCH OF TEST DIAGRAM

1.3

Water pump/pressure

recorder

Fig. 1

SCHEMATIC DIAGRAM OF N2 PURGE