In order to assess whether pipeline pigging is a viable option, there are a number of considerations that must be taken into account. The following are some of the main pigging considerations that are commonly used by maintenance crews around the world.
Pipeline Pigging Considerations:
Desired Result: The length of pipe and type of fittings to be negotiated and pressure and flow available will determine the type of pig and frequency it may be run. Removing liquids such as water, oil, condensate or even product such as yogurt from a line will require a high sealing pig like the Foam Disc Pig or VIPRS®. Removing wax could require more rigid discs, but will bypass to keep the wax moving ahead of the pig. Tight radius bends could require an all urethane pig like a Uni-Flex® or MULTI-CAST™. When frequent maintenance pigging is required perhaps replaceable discs or cups, such as our BD-6 Series pig configuration, may be more economical.
Pipeline Design and Fittings: The pig launcher and receiver are two important fittings in pipeline pigging. The launcher is used to introduce the pig into the pipe and the receiver collects it once the cleaning job is done. Safety closures prevent accidents from happening by limiting access to the pipeline while it’s under pressure to retrieve the pig. Dust bags can be used to catch dust and debris removed by the pig. Barred tees will prevent the pig inadvertently traveling into a branch line, and long radius bends aid the progress of the pig.
Valve and Internal Obstructions: Pipes with varying internal diameters and valves could prove to be a challenge during pigging. In light of this, before any pigging starts, it’s important to clearly establish if there are any internal features that might affect the pig’s progress. This will help maintenance crews use appropriate pigs and pigging methods.