2022 Project of the Year Winner – Retention & Detention: Steelpointe

By: Lane Enterprises, Inc

Steelpointe is a 37 acre mixed housing development on the former industrial site of Phoenix Iron Works, located in Phoenixville, Pennsylvania, now the heart of Chester County’s largest historical district.

steelpointe perforated retention system

Phoenix Iron Works was a manufacturer of iron and related products during the 19th and early 20th centuries. Company facilities are a core component of the Phoenixville Historic District, a National Register of Historic Places site that was recognized in 2006 as a historic landmark by ASM International, formerly known as the American Society for Metals.

Steelpointe is the namesake of the old industrial operations to which the historic preservations point and a fitting proleptic to the type of buried storm water management system (SWMS) that would be installed beneath the open area in the midst of the development, particularly so because the SWMS was originally specified and designed as a plastic stacked modular system.

There are a number of plastic modular SWMS’s on the market today but they all suffer from the same stigmas – they are labor intensive, expensive, and installation sensitive. When it came time to make things right, the contractor approached the developer with a better way – corrugated steel pipe.

steelpointe perforated retention system

The original SWMS design conformed to the triangular shape of the development’s open space. In order to utilize the same footprint the corrugated steel pipe alternate needed to be slightly deeper. The alternate eventually approved was a 90-inch diameter, 14 gage, 5 x 1, fully perforated system. While providing water storage in the pipe system proper, the perforated pipe serves the dual role of providing additional storage in the open-graded backfill embedment to meet total storage requirements, as well as allowing water to infiltrate into the ground consistent with the original design.

steelpointe perforated retention system

The total storage of 173,761 cubic feet provided by the 90-inch CSP system was just slightly more than the original design (172,140 cubic feet). The main feature touted for the plastic module systems is their high void space (95% or greater). However, that feature is virtually lost in comparison with perforated corrugated steel pipe and the ability to utilize the voids in the stone embedment for additional storage.