Hydrotest is often carried out after a construction or maintenance activity of a piping system. It is more significant to Hydrotest piping after a new piping system is installed, it is essential to the commissioning activity.

Need to Hydrotest

After new piping is laid in the plant or facility. There are multiple reasons to Hydrotest a line. Few of which are listed below:

  • To verify the integrity of the piping system.
  • To ensure the safety and reliability of the piping system.
  • To check out the weld joints’ quality.
  • To make sure the system is leak proof.
  • To relieve the stresses from the system.

Equipment required for Hydrotest

  • Pump – To create pressure inside the system
  • Hose and fittings – To connect the pump, piping system, and other equipment
  • Test medium – Most of the time water is used as a test medium
  • Pressure Gauge – To measure inside pressure. The range of gage 1.5 to 4 times the Hydrotest pressure.
  • Temperature Gauge – To notify the allowable temperature
  • Torch Flash – For visual inspection of leakage
  • Torque wrench – For proper tightening of joints
  • Supports- To fix the pipe or vessel, before the test starts

Properties of water used for Hydrotest

The water used for Hydrotest must-have characteristics near to potable water, which is as follows:

  • Percentage of Hydrogen (pH) – should be between 7 to 8.5
  • Water Hardness – it should be between 150 – 400 ppm
  • Calcium Hardness (Ca) – it should not be more than 80 ppm
  • Magnesium Hardness (Mg) – below 40 ppm is acceptable
  • Iron Content (Fe) – should be within 0.3 ppm
  • Turbidity – allowed till 10 – 20 ppm
  • Total Suspended Solids (TSS) – Should NIL
  • Temperature – it should not be less than 17°C

Quantity of water required for the test

The quantity of water can be calculated by using the following formula:


d = Diameter of pipeline

L = Length of pipeline

V = Gallons of water required

Categories: P