However, there is no consensus among volcanologists on how to define an active volcano. As of 2012, PHIVOLCS lists 23 volcanoes as active in the Philippines, 21 of which have historical eruptions; one, Cabalian, which is strongly fumarolic volcano [further explanation needed]; and one, Leonard Kniaseff, which was active 1,800 years ago (C14).
Polyvinyl Chloride PVC. Polyvinyl Chloride (PVC) is a major plastics material which finds widespread use in building, transport, packaging, electrical/electronic and healthcare applications.
Polyvinyl chloride (PVC) pipe is made from a plastic and vinyl combination material. The pipes are durable, hard to damage, and long lasting.They do not rust, rot, or wear over time. For that reason, PVC piping is most commonly used in water systems, underground wiring, and sewer lines.q33: PVC is made using chlorine gases and is usually pretty stable after production. Pipe that is manufactured for the purpose of waste water transfer should not be used to hold drinking water, or allow the polymer to break down through sanding or heat being applied.