Inspection and condition monitoring of insulated chiller water pipe lines

Challenge Details

There is approximately 100 km of chiller water pipelines in our plant with pipe diameter ranging from 50mm to 300mm.  These pipelines are distributed all over the plant at a height of 20-50 m from the ground. The pipe network has welding at every 6m along with bends and pipe fittings. The ambient temperature around the pipeline varies from 40-75 °C. These water lines are insulated with thermocol, steel wire mesh and the outer layer with cement or Aluminium sheet. Many a time, there is condensation at the surroundings which lead to rusting and weakening of the pipe. The supports of pipelines are metallic and have no insulation which causes condensation and hence rust.

Since the chiller water lines run all across the plants, leakages can lead to water ingress and damage the spares/equipment. The breakdown in the chiller water network poses a serious safety issue due to the location of the pipelines in places like torpedo area, or near the power rails of EOT cranes. Currently, the insulation has to be ruptured at random places to know the condition of the pipeline. After measuring the thickness using ultrasonic testing, the pipe is re-insulated at the ruptured portion. If ultrasonic testing is used directly on the top of the cemented portion, variation in thickness measurement readings is huge due to the metallic portions of wire mesh and support hinges. Hence, the accuracy of the readings is doubtful. Moreover, the current method is time-consuming and requires a lot of re-work.

Additional Details:

• The pressure of the chiller water - Supply Chiller water flows @ 0.6 CMH/TR from chiller @ 7 - 10 °C to AHUs through CHW pumps and Return back to chiller from AHUs @ max 15 °C. Nominal pressure considered as per the system requirement (min 2.0 Kg/cm² to 10 Kg/cm²).
• The flow rate of water - For CHW 0.6 CMH/TR and TR varies from 40 to 3500 CMH/TR
• The temperature of chiller water in the pipeline - 7 to 10 °C
• The thickness of insulation - Outer Tube Dia with cladding is max 4”.  Pipe Diameters- 5/8" or 3/4" or 7/8" dia (depends upon the capacity of chillers).

Thus, we want to inspect the pipes without rupturing the insulation and plan the repair & maintenance based on the inspection.

Success Criteria:

• Easy inspection at all working heights and at high ambient temperatures (up to 70 °C)
• The inspection mechanism/device must be handled and fixed on the waterline with minimum effort without hindering /fouling the other lines passing nearby. The operation should be easy.
• The solution must be environment-friendly.