The pig immersion method is used for locating non-metallic pipelines such as PE, PVC or AZ. Pipelines made of such materials cannot be located using conventional electromagnetic location methods.

For pig immersion, a device called pig is introduced into the pipeline under pressure through a launching station (tapping sleeve at a flange, bleeder valve, bypass or similar). In the water flow, the pig opens up like a parachute and tows a locating cable into the pipeline through a pressure-tight lock. Once the desired distance is reached, a trigger mechanism is actuated to turn out the parachute.

After location, cable and parachute are then drawn back out with ease. Once the pig is back in the tapping sleeve, it can be removed from the pipeline through the lock during normal operating state under pressure.

During pig location, sediments or incrustations can be loosened, so it can be necessary to flush the pipeline according to the standard operating procedures once the locating is finished.

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