A mil equals 0.0254 mm, so a 60-mil HDPE liner is about 1.5 mm thick and a 40-mil sheet about 1.0 mm. Thickness is measured at many points across each roll, and specs set both a minimum average and a minimum single reading, with textured sheet measured at its core. A mil is not a millimeter, and mixing the two on an order is an expensive mistake.
Floor is 60 mil smooth and the sump is 80 mil, so check the roll tags before they unroll anything.
Also heard as
- mils
- thou
Related terms
Geomembrane
Low-permeability polymer sheet used as a liquid or gas barrier in liners, covers, ponds and tunnels.
HDPE
High-density polyethylene: the stiff, chemically resistant polymer used for most landfill and mining geomembranes.
LLDPE
Linear low-density polyethylene: a softer, more flexible geomembrane polymer that follows uneven ground better than HDPE.