In addition to ASTM International, N-12 HP (for “high performance”) 12- through 60-in. dual- and triple-wall corrugated pipe meets American Association of State Highway and Transportation Officials standard MP21-11 for surface and subsurface drainage. Made from engineered impact-modified co-polymer polypropylene resin, all diameters have an extended bell and spigot with dual gaskets for joint integrity. Comes in 13- and 20-ft. lengths.
Advanced Drainage Systems Inc.