Short for polyvinyl chloride, PVC geomembranes get their flexibility from plasticizers, so they drape well over rough ground and can be factory-welded into large panels that are folded and shipped. Factory seams are dielectric welded, field seams with solvent, hot wedge or hot air, and lapped seams are often checked with an air lance. Long exposure to sun or some chemicals draws out plasticizer and stiffens the sheet, so PVC is usually covered.
PVC panels are factory-welded into one big piece, so we just unfold it and make two field seams.
Also heard as
- polyvinyl chloride
- vinyl liner
- flexible PVC
Related terms
Geomembrane
Low-permeability polymer sheet used as a liquid or gas barrier in liners, covers, ponds and tunnels.
Air lance
Nozzle that blows compressed air at the edge of a lapped seam to find unbonded spots in thin, flexible liners.
HDPE
High-density polyethylene: the stiff, chemically resistant polymer used for most landfill and mining geomembranes.