HYDRO TESTING FOR GRP 300 mm PIPE LINE As per section 40 05 15

Contents

1. General

2. Backfilling

3. Inspection

4. Preparation

5. Equipment

6. Valves & fittings

7. Tools

8. Man power

9. Water Filling

10. Pressurization

11. Depressurization

12. Pressure testing Safety

1. General

The procedures are compiled for uniformity and to assure all level of staff is aware of the procedure to ensure the quality of the jointing process.

The objective is to ensure that the installed piping system will meet the specified performance requirements.

2. Backfilling as per ( Section - 31 23 16 )

Prior to the testing process, the pipe system shall be back filled as described below. This back-fill procedure will prevent extreme movement of the system while pressurizing.

2.1 Pipes shall be completely back-filled and compacted except for the pipe joints that must be left exposed for inspection.(Only straight sections)

2.2 Elbows assembly plus 20 meter of straight pipe before and 20 meter pipe after the assembly including joints shall be backfilled completely and compacted.

2.3 The sand cover from the pipe crown shall be minimum 500mm for straight pipe sections without elbows. For elbow section the sand cover shall be minimum 600 mm from the crown of the pipe.

2.4 Unsupported sections shall not exceed the two times of the diameter.

3. Inspection As per ( Section -01 43 00 )

It is important to conduct a visual inspection throughout the system prior to the testing process, to identify any external damage that may have occurred during the installation/handling process of the pipe. If any damage occurred it should be repaired. Ensure that all the joints are cured properly before starting the testing. As required by our quality and standards.

4. Preparation for pressure test as per ( section 40 05 15 )

a) A formal risk assessment should be carried out prior to the hydro test.

All supports, guides and anchors shall be in place prior to pressure Testing.

b) Temporary supports and restraints shall be added if required unless stated otherwise

c) All valves shall be through body rested. Piping containing check valves shall have the source of test pressure located in downstream side.

d) Ensure completion of backfilling/plugging is completed prior to Hydro testing upon completion of the pipe line section.

e) All the flange connections are properly tightened to the required torque as per the procedure. Any permanent valves in the system shall be kept fully open. Arrange all necessary equipment i.e. filling pump with feed tank, pressure pump, gauges etc. The End caps/blind flanges with required connection for air venting shall be available to close the system once the water filling process is completed.f) Conduct pressure test only on exposed joint of pipe line.

g) Provide temporary drain line to carry testing fluid away from the pipeline being tested. Remove temporary drain line after completing the pressure test.

h) The test pressure shall be 15 bar for 4 hour on hold.

5. Equipments used a. Water tank b. Connecting hose pipec. Diesel water pumpd. Boom truck

6. Valves and fittings as per ASTM / ANSI B16.34a. Check valveb. Relief valvec. Threaded nippled. Coupling

7. Tools use

a. Certified hydro test manifoldb. Certified pressure gaugesc. Water hose couplingd. Spanners

8. Man power used a. Boom truck operatorb. Hydro test supervisorc. Hydro test techniciand. Labors e. Safety officer f. Mechanical QC inspector

9. Water Filling , Potable water quality as per ( SAES-A-007 )

The system shall be flushed prior to the hydrostatic testing. The flushing of the system shall be carried out from the highest point of the pipeline. Potable water or equivalent shall be used for this purpose. Prior to commencement of pressure test. Ensure that the flushing continues until clear water appears. Once the flushing is completed water can be filled to the system from the lowest point of the pipeline in a steady and controlled manner. Fill a large amount of water into the system. Ensure all the vents and drains are opened while filling water in the system. Adequate care shall be taken to venting the system to avoid any air trap inside the pipeline, which may give erroneous results. The water filling stage is completed when the water starts coming through higher vents, stop the water pumps and check the flanges, valves and connection for any weep age and leakages.

10. Pressurization , As per specification ( GI0002.102 para 5.16 )

After the filling process is completed, seal the entire test section with the required end caps/blind flanges keeping all valves fully opened. A devise capable of continuously pressurizing the test section shall be connected to the pipeline with the required pressure recorders. A pressure gauge shall be connected to the highest point of the pipeline. All pressure gauges, recorders shall be calibrated prior to use in the system. Start pressurizing the system gradually and in a steady and controlled manner .The rate of pressurization shall not exceed 1 bar per minute and allow the system to stabilize. Once the stabilization time is completed, continue pressurizing the system gradually to the required test pressure (1.5 x working pressure) and maintain the pressure for 2 hour for the leak test.

Upon completion of pressurizing the system, dismantle the hose connection from the pressure pump and seal the ends with suitable plugs. The entire pipeline shall be carefully inspected for any leakage from the joints of the pipe body. The test pressure in the system shall be closely monitored and be maintained to the required test pressure. Visual inspection of joints shall be carried out at least 6-8 hrs.

Pressure drop may occur due to the following reasons:

a. Temperature variation between day and nightb. Leakage of accessories connected to the systemc. Leakage from the gasketsd. Dirt at sealing area e. Leaking test equipmentf. Stabilizing time too shortg. Leaking from the jointh. Leakage of pipe as a result of damage (cracks)i. Settlement of the pipeline systemIf any leak is observed from the flange connections, it is not permitted to torque the flange under pressure, the line should be depressurized fully and then the flanges to be tightened. If the flange or gasket is found to be damaged it shall be replaced with a new one.

If a leakage is observed on the pipe body or the joint, the test shall be terminated and the leaking joint/pipe shall be repaired.

If no leakage or weeping is observed during the inspection, the hydrostatic test is successfully completed and the system is ready for use.

11. Depressurization , As per Specification ( GI0002.102 para 5.19 )

The depressurization of the system shall be carried out carefully to avoid any negative pressure in the system. All the vents shall be kept open to allow adequate air into the system while draining the pipeline. Water shall be drained slowly and in a controlled manner. After completion of hydro test and draining the water from the system, temporary flanges should be cut out and removed. Ensure proper end plugging to avoid dust contaminations.Dewatering of small /medium section shall be done through gravity draining.

12. Safety and precautions.

All precaution shall be taken while testing the system a. The test area shall be barricadedb. Place warning signs at all adjacent areasc. Experienced personnel shall operate test equipmentd. Only authorized personnel shall be involved in the test or inspection operatione. Only one person shall be in-chargef. Do not change anything in the pipeline when it is under pressure.g. The testing equipment shall be installed at a sufficient distance from the pipelineh. Proper safety precautions shall be followed under supervision of Safety officer/Jointing Supervisor.

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