The ADS LandMax Retention/Detention Pipe Systems document covers pipe requirements, joint performance, fittings, material properties, and installation information. It includes a typical retention/detention cross section diagram for reference.

Pipe requirements for ADS Retention/Detention systems may utilize any of the various pipe products listed: N-12® ST IB pipe (per AASHTO) shall meet AASHTO M294, Type S or ASTM F2306, N-12 ST IB pipe (per ASTM F2648) shall meet ASTM F2648, N-12 MEGA GREEN ST IB shall meet ASTM F2648, N-12 WT IB pipe (per AASHTO) shall meet AASHTO M294, Type S or ASTM F2306, N-12 WT IB pipe (per ASTM F2648) shall meet ASTM F2648, N-12 MEGA GREEN WT IB shall meet ASTM F2648s shall meet or exceed the soil-tight requirements of ASTM F2648.

All products shall have a smooth interior and annular exterior corrugations. All ST IB pipe products are available as perforated or non-perforated. WT IB pipe products are only available as non-perforated.

Product-specific pipe specifications are available in the Drainage Handbook Section 1 Specifications.

Joint Performance varies by product. ST IB pipe shall be joined using a bell & spigot joint. Plain End pipe & fittings connections shall be joined with coupling bands covering at least two full corrugations on each end of the pipe. Gasketed soil-tight coupling band connections shall incorporate a closed-cell synthetic expanded rubber gasket meeting the requirements of ASTM D1056 Grade 2A2. Gaskets, when applicable, shall be installed by the pipe manufacturer. Watertight WT IB pipe shall be joined using a bell & spigot joint. For additional details refer to Technical Note 7.01 Rainwater Harvesting with HDPE Cisterns.

Fittings should conform to ASTM F2306 and meet joint performance requirements indicated above for fitting connections. Custom fittings are available and may require special installation criteria.

Installation shall be in accordance with ASTM D2321 and ADS recommended installation guidelines, with the exception that minimum cover in trafficked areas for 12”-60” (300 to 1500 mm) diameters shall be one foot (0.3 m) and for 42”-60” (1050-1500 mm) diameter the minimum cover shall be 2 ft. (0.6 m) in single run applications. Backfill for minimum cover situations shall consist of Class 1 (compacted) or Class 2 (minimum 90% SPD) material. Additional installation requirements are provided in the Drainage Handbook Section 6 Retention/Detention.