Pipe maker Advanced Drainage Systems Inc., Hilliard, Ohio, introduced a new family of N-12 HP (high performance) corrugated PP pipe in April. It includes triple-wall pipe up to 60 in. OD. Triple-wall PP pipe is made in Europe up to about 20 in. OD, but was not produced here before now. The large triplewall pipe “far surpasses” any other corrugated pipe product, ADS says, and will be the first polyolefin pipe to compete with concrete and PVC for sanitary sewers. The smooth outer wall allows easier backfilling and installation than a corrugated profile, filling the space under the pipe with less opportunity for deflection. The key is die profiling of the outer wall, which is extruded separately over the dual-wall pipe. ADS’s patent application (U.S. 20060201567) describes an outer wall with concave sections aligned with corrugation crests and convex sections with corrugation valleys. This creates reinforced rings around the pipe, which resist deformation. A new joint design has dual interlocking sections to improve leak resistance. ADS applied for an ASTM standard for dual-wall PP pipe up to 30 in. diam. in April 2007 and for triple-wall PP pipe up to 60 in. wide earlier this year. ADS expects both standards to issue next year. Pipe will be produced at several ADS locations and be available nationwide. (800) 821-6710• www.ads-pipe.com
Editor PickSizing the Barrier Gap
Here’s a less complex way to properly size the barrier gap for barrier screws.