Over the course of their lifetime, Tampa Bay's raw water pipes need continuous routine maintenance in order to function properly and safely deliver water. Without it, they can be subject to debris, corrosion, and structural failure. Cleaning pigs assist in all areas of pipeline maintenance, including debris removal, as well as helping to clear air out of any lines.
A crucial benefit that cleaning pigs provide is that while they are in use, a pipeline can often still function normally with no interference. Very important for a large metro area like Tampa Bay, that depends heavily on functioning pipelines. Several different sizes of pigs are/can be used in conjunction; for example, a larger pig may be sent into a pipeline for heavy cleaning, followed up by lighter pigs to clean up whatever is left over.
Pigs come in all sorts of different shapes and styles. They can have a gel coating on the exterior, or have a bullet shape, flat ends, or even a crossing pattern style with embedded silicone carbide. Shape dictates the speed in which a pig travels in the pipe, and a faster pig is able to remove more stubborn debris and buildup. Pigs with gel coating are more commonly used for general or light cleaning, while pigs with silicone carbide are used for cleaning lines with buildup or corrosion (this is because the silicone carbide has a rough coating). Additionally, foam pigs offer flexibility when a project requires cleaning pipes with bends or changing-diameters.
Another type of pig is called a "Mandrel"; Mandrel pigs have a metal exterior that contains seals, discs, and scraping equipment. In addition to cleaning and sealing, they can be used to check a line for its diameter, as well as drying lines when needed. Mandrel's have attachments for additional debris-scraping discs, as well as attachments for additional cups and brushes.
Lastly, different pipelines require different pigs. Cleaning a PVC pipe with plastic-bristle foam pigs is okay as the bristles will not remove the coatings and will take care of most of the build-up. A gas line with internal coating will be cleaned by a polyurethane pig, as it doesn't have external cleaning equipment that can harm or remove the coating. If there was no coating, a cleaning pig that is equipped with brushes could be used. Polyurethane pigs are also ideal for cleaning an oil pipeline (or something comparable) as they are strong enough to remove internal wax buildup or even water.
With a population of over 3 million people, it is imperative that Tampa Bay's pipes are inspected and cleaned on a regular basis for the people who depend on them.