Pipe Laying

Pressure Test

Fill pipe line with water

For the pressure test, The water filling process was carried out slowly verifying that air is being released from the pipe line. It was very important to make sure that air was actually being released during this process as the pipe line would become dangerous because of the compressed air caused by the insufficient air released.

If water leakage was discovered during this process, the pipe line must be repaired immediately.

The pipe lines were left in the water filled condition at least 24 hours to stabilize the pipe line.

Before applying the specified test pressure, air was that be expelled completely from the pipe, valve, and hydrants. If there was not permanent air vents at high points, the corporation cock was installed at such points so that the air can be expelled from it.

Installed equipment required for pressure test

The necessary equipment for the pressure testing work may be prepared as follows.

  • Pressure pump                                                1 set
  • Pressure gauge                                                1 set
  • Pressure recorder                                          1 set
  • Suction hose                             necessary length
  • Connection hose                     necessary length
  • Overflow hose                          necessary length
  • Water tank and water meter                      1 set
  • Connection pieces                                         1 set

Perform pressure test on pipe line


Each valve section of pipe was filled with water slowly and the specified test pressure based on the elevation of the lowest point of the line or section under test and corrected to the elevation of the test gauge. Valves were not

operated in either the opening or closing direction at differential pressures above the rated pressure. Any exposed pipe, fittings, valves and joints were examined carefully during the test. Any damage or defective pipe, joint, fitting, valves that were discovered was repaired.

Leakage tests

If a drop in pressure occurs, the quantity of water added to re-establish the test pressure were carefully measured. This should not exceed 0.1 liters per millimeter of pipe diameter per kilometer of pipeline per day for each 30m head pressure applied.

Drain pipe lines

After the completion of the test, water was drained from the pipe line. If the adjacent pipe section is to be tested, the water may be available for the next test.


Removal of protective work from the ends of test section

Protective work at the ends of the test section was removed when this pipeline is to be connected to an adjacent pipeline. However, when the adjacent pipeline was tested, these same protections may be available for it.

After the adjacent pipe line has been tested, the test section was connected to it.

Pipe Laying

Pressure Testing

Pressure Testing mean, A newly installed pipeline has to be tested to check the reliability of its performance before being brought into service.

The flow chart of the field hydrostatic test was shown below.

Decide of pressure testing section

The test section has to be determined after considering pipe line conditions and site situations, for example, the ups and downs of the pipe line, the position of valves and air valves, and the space for testing, the availability of testing water,

the number of joints, and other factors. While the test section was determined, the position of the valves and the valve chambers must be considered, because the valve and valve chamber can be useful as terminal points for the end of the test section.

Decide test pressure

The test pressure was determined by referring “installation of Ductile Iron Water Mains and Their Appurtenances”

Test pressure restrictions

  • Test pressure should not less than 1.25 times the working pressure at highest point of the test section.
  • Not exceed pipe or thrust restraint design pressure.
  • Be of at least 2 hours duration

Perform protective work at each end of the test section

  • Protective method using a valve chamber

If a valve chamber had enough capacity of install the equipment and apparatus required for pressure test, it can be used simple to carry out the pressure test inside since the valve chamber were designed to be able to resist the force of the water pressure when the valve was shut off.

Other protective methods

If a valve chamber cannot be used for the pressure test, protection for the end of the test section can be anchored by bolts (end cap)