How PVC pipe is made

PVC is the world's third most widely produced plastic, and pipe is one of its biggest jobs.

stations: 5
things upstream: 22
raw sources: 9
steps from the ground: 6

The short version

PVC pipe is extruded. White PVC resin powder is blended with stabilizers and other additives, melted in a screw extruder, and pushed through a ring-shaped die. The soft tube is cooled in water, hauled along at a steady speed, cut to length, and one end is flared into a socket.

Blend the compound

PVC powder is mixed with a heat stabilizer, white titanium dioxide pigment and other additives. Pipe for pressure or underground use has no plasticizer, so the plastic stays rigid.

Goes in
PVC Titanium dioxide
Melt it in the barrel

A rotating screw drags the powder along a heated barrel, where it melts into a thick paste. PVC is more heat-sensitive than other common plastics, so the temperature is watched closely.
Extrude through the die

The melt is pushed through a ring-shaped opening around a central core, which forms a hollow tube of continuous length.
Cool in water

The soft tube passes through water tanks that set its shape.
Cut and flare

A saw cuts the tube to length, and one end is heated and flared into a socket that the next pipe fits into.

End of the linePVC pipe

Worth repeating

PVC is the world's third most widely produced synthetic polymer, after polyethylene and polypropylene.
German chemist Eugen Baumann first synthesized the plastic in 1872.
Near 250 °C it starts to degrade, while polyethylene is stable to 400 °C.