Major members of the sewer-main pipe manufacturing industry and the University of Houston have completed and published the results of the following two research projects:
- The Sewer-Main Collection Pipe Joint Infiltration Testing research project that measured the water infiltration rate of water-tight designed 30-inch pipe joints. The joint tightness testing was conducted at a minimum hydrostatic head of 15 feet (i.e., 7 psi) under axial, shear loaded and angularly deflected conditions.
- The Life Cycle Cost Model research project developed an interactive model to estimate the costs of constructing, rehabilitating, operating and maintaining sewer mains under various infiltration levels over a 30-year life. The model has been calibrated with published data and may be used to compare different rehabilitation and maintenance scenarios to identify the most cost effective sewer main design.
Infiltration Infrastructure Damage
Ancillary costs such as infrastructure damage (e.g., roadway settlement, sink holes) are not included in the Life Cycle Cost Model and may be factored in from local conditions. As an example of potential infrastructure damage, this paper includes a case study showing the impact of joint infiltration in the city of Houston.
Project Costs and Funding
The two research projects were funded by participating industry members and the Environmental Protection Agency Office of Wastewater through a grant to, and administered by, the Fiberglass Tank & Pipe Institute. Fourteen Steering Committee members contributed some $50,000 and over 2,000 professional man-hours to the project from 2000 through 2003. This includes the cost of pipe joint testing paid for by the manufacturers and time attending a series of daylong meetings. By applying a value of $125 per hour for these professional services, industry’s total contribution is some $300,000 plus the $100,000 EPA grant for a total project cost of $400,000.