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Arizona State University Utility Tunnel Systems Evaluation

The Tempe campus is the oldest and largest of Arizona State University’s (ASU) four campuses. With extensive infrastructure and distribution systems, all utilities are delivered to campus buildings through a five-mile network of tunnels. These systems are supported by a central plant (CP) and a combined heat and power plant (CHP), both of which are primary to the production of the thermal and electrical utilities.

While the majority of the campus’ thermal production facilities have been renovated or upgraded in the past 10 years, almost all of the of the 20,000-linear-foot utility tunnel system and associated distribution systems are original 1937 construction.

With more and more frequent emergencies and crumbling infrastructure, supported by many years of partial funding, ASU’s deferred maintenance costs have significantly compounded. To assist in identifying critical problem areas, prioritizing needs, and obtaining funding, Stanley Consultants performed an infrastructure condition assessment to study and evaluate the mechanical systems within the tunnels as well as the integrity of the tunnels themselves.

Our assessment included visual observations and ultrasonic pipe testing. We located and assigned a station number for each of the expansion joints, steam traps, valves, guides, and anchors that were evaluated. This included over 4,000 devices within 4+ miles of the tunnel system. For the systems identified below, special attention was focused on condition of the expansion joints with regard to expansion travel, joint alignment, insulation, and packing leakage.

In our evaluation report, we prepared stationed general arrangement drawings of the campus utility tunnels and developed equipment/structure tables to identify those distressed mission-critical systems that could impact campus utility reliability and life safety. We then ranked each to help ASU establish maintenance priorities for performing the necessary repairs.

Next, we performed conceptual cost estimating for those distressed mechanical and structural systems to assist ASU in determining if repair or replacement will be more feasible and cost-effective, and to aid in requesting funding.