The hydraulic capabilities of the product were significantly improved in 1987 when ADS introduced the first HDPE drainage pipe to combine an annular corrugated exterior for strength with a smooth interior wall for maximum flow capacity. Named for its excellent Manning’s “n” rating of 0.012, N-12 pipe was designed specifically for storm sewers, high ways, airports, and other engineered construction. Through extensive field and university testing, ADS engineers were able to refine the corrugated wall design for larger diameters without compromising the pipe’s excellent strength-to-weight ratio. Its performance and economy have led to rapid acceptance by contractors and engineers, and official approval by state and municipal agencies.
Gone are the days when plastic pipe was specified only for cost reasons. Advances in polymer science and structural design have created a product that has actually outperformed and outlasted concrete and metal pipe while maintaining its cost advantage. By any measure, ADS N-12 pipe compares favorably to conventional materials.
Structural Strength. As flexible conduit, HDPE pipe withstands vertical pressure by transferring most of the load to the surrounding soil. N-12 pipe will support H-25 live loads with 12″ minimum cover, and E-80 loads under 24″ cover. Maximum cover will vary with design conditions, but can usually be specified up to 60 feet. In controlled tests, N-12 has performed well at fill heights of more than 100 feet.
Durability. High density polyethylene is an extremely tough material that can easily withstand the normal impacts involved in shipping and installation. It is highly resistant to chemical attack and is unaffected by soils or effluents with pH ranges from 1.5 to 14.
HDPE’s ductility and molecular structure result in excellent resistance to abrasion. Polyethylene pipe shows less than 20% of the material loss of concrete pipe in abrasive environments, and is often specified for harsh mine slurries and as a slip liner for deteriorated culverts.
Hydraulic Efficiency. The smooth interior of N-12 pipe provides superior flow characteristics. Test on various sizes of N-12 pipe show Manning’s “n” values ranging from 0.010 to 0.013. (It should be noted that “n” values tend to increase with slower velocities and larger pipe sizes.)
Light Weight. HDPE pipe is 30 times lighter than concrete pipe, making it far easier to transport and handle. On-site labor and equipment requirements are reduced, with a corresponding reduction in the potential risk of injury.
Fast Installation. Long 6 m (19′ 8″) lengths mean fewer joints. (N-12 pipe is also available in 13 ft lengths for smaller trench boxes.) The pipe cuts easily and does not need to be beveled for joining. In typical trench depths of 6 to 100 ft, contractors report installation rates ranging from 1,200 ft per day of 15″ – 24″ pipe to more than 400 ft per day of 60″ pipe.
N-12®Pipe: The first corrugated high density polyethylene drainage pipe with a smooth inner wall for superior hydraulics and maximum flow capacity.
Integral Bell and Spigot Joints: N-12 pipes for different applications are engineered for fast installation of long straight sewer lines that require soil tight or water tight joint performance.
Hinged Split Couplers and Fabricated Fittings: provide cost effective connections for normal drainage installations. ADS can fabricate virtually any fitting as long as it meets engineering standards.
Pro Link® molded HDPE Couplers: are available on fittings and repair couplers to meet specific joint performance requirements and provide installation savings.
Series 35® Thermo-molded PVC Sanitary Fittings: meet the 10.8 psi pressure testing requirements of ASTM D3212. Selection includes couplers, tees, wyes, elbows, caps and adapters, each fitted with an O-ring seal. The fittings connect not only corrugated HDPE pipe, but also PVC, concrete and other materials.
The material cost of HDPE is extremely competitive with concrete and corrugated metal. When installation costs are factored in, the savings start to multiply.
- Polyethylene’s light weight cuts shipping charges. More lengths of pipe per truck means fewer delivery loads.
- Fewer people are needed for on site unloading, handling and even installing.
- Heavy equipment requirements are reduced.
- Long lengths are easy to handle and require fewer joints.