Tsurumi Fuel Terminal
In mid-1998 Japan District completed a unique project, the Tsurumi Dome. The project built a geodesic aluminum dome roof atop Tank 603 at the Tsurumi Operating Unit No. 1 (OU-1) Fuel Terminal. The terminal, operated by Yokosuka Naval Base's Fleet and Industrial Supply Center's Fuel Department, is in the Yokohama harbor between Yokohama City and Haneda. It presented several unique challenges for the district and is one of the first domes of its type in Japan. Successful completion of the project required teamwork between several agencies. The geodesic design of the new dome is apparent both inside and out during construction. The project was just a small portion of a larger contract that teamed three U.S. Army Corps of Engineers districts. The Defense Fuel Supply Center (DFSC) (now the Defense Energy Support Center) at Fort Belvoir, Va., funded the project. The venture called for designing and building geodesic aluminum dome roofs over six floating roof, bulk fuel storage tanks. Five tanks were at the Defense Fuel Supply Point (DFSP) at Manchester, Wash., and the sixth tank was Tank 603 at Tsurumi OU-1. Louisville District worked with DFSC to solicit and award the project as a design-build contract. Following award and design, Louisville District transferred construction to Seattle District to oversee work at Manchester, and to Japan District to oversee work at Tsurumi. Louisville District prepared the solicitation package with the assistance of Japan and Seattle districts to ensure site specific contracting and construction requirements were included. The contract award committee included members from all three districts.
In September 1996, Louisville District awarded the contract to TEMCOR, a California-based company specializing in designing and building aluminum clear span structures. Louisville District oversaw design of the domes and in August 1997 transferred the construction at Tsurumi to Japan District. The district issued TEMCOR a notice to proceed with building on Sept. 30, 1997. After initial construction submittal review and acceptance, work on the project began last Jan. 12.
Another unusual aspect for Japan District was that the project's prime construction contractor was a U.S.-based company. Japan District normally oversees construction contracts awarded to local Japanese contractors. Since TEMCOR did not have all the requisite licenses to build in Japan, all the labor at Tsurumi had to be sub-contracted to a licensed construction contractor in Japan. TEMCOR selected Nippon Hodo as its subcontractor.
The work at Tsurumi first called for cleaning and vapor freeing the fuel tank to ensure a safe working environment. Next, the contractor made various tank modifications such as removing projecting points so all the tank parts would fit under the new dome roof. Modifications to the tank also included adding a new gauging pipe and gauging platform. The last major stage of work was building the dome.
TEMCOR, as the prime contractor, sent a site superintendent, Shawn Michaels, to oversee Nippon Hodo's work and the dome construction. Nippon Hodo did the tank cleaning, vapor freeing, and modifications. TEMCOR made all of the aluminum dome parts at its plant in California and shipped the material, along with special tools, to Japan.
Since the Nippon Hodo crew had never built a geodesic frame structure, Michaels had to explain and demonstrate each step. This included tasks from laying out and connecting the aluminum members of the geodesic frame, to installing specialized bolts to connect the members. All this through an interpreter. Even with an untrained crew, Michaels and his crew built the dome and secured it to the top of the tank in less than 20 working days.
TEMCOR's simple yet functional design, plus its complete, accurate production and delivery of the materials, plus Nippon Hodo's dedicated crew, made such productivity possible. They completed the project on March 30 four days ahead of schedule. Most of the work involved significant safety risk. Besides the inherent fire hazards of working in a fuel terminal, the tank cleaning work was performed in a permit-required confined space, and fall protection precautions were needed for work on top of the tank. Tank modifications also required welding both outside and inside the fuel storage tank.
The Tsurumi Fuel Terminal emptied the tank before start of the tank cleaning work and kept several adjacent tanks empty to permit safe welding. The Fleet Activities Yokosuka Fire Department assisted in issuing welding permits and ensuring the site conditions were safe. Its personnel also assisted the dome leak test by providing a water pump truck, hoses, and crew. The crew sprayed water on the dome roof so the contractor could identify leaks that required re-caulking.
Until 1998, Japanese law required steel tank roofs for all fuel storage tanks. Typically, floating roof tanks are sealed at the edges with rubber gaskets. These seals, left exposed to sunlight, will degrade and eventually allow water to seep along the sides of the tank and into the fuel. With a dome atop the tank, rainwater is diverted to the outside of the tank.
Another significant benefit of an aluminum dome roof is that it reflects much of the sunlight, which keeps the fuel at a lower temperature, thus reducing loss by fuel evaporation. The savings in fuel retained can help recover the cost of building the dome roof.
The geodesic frame pattern and the use of lightweight aluminum for both the framing and the panels permit the roof to span the entire diameter of the tank (119 feet) with no intermediate supports. Teflon pads on the connection plates between the aluminum frame and the steel tank allows the frame to expand and contract with heat and cold and separates the aluminum roof and steel tank to prevent corrosion. Silicon seals keep the dome relatively maintenance free. TEMCOR provided a four-year warranty of the work.
With the 1998 change to Japanese law, there is significant interest in Japanese industry to build more dome roofs over fuel storage tanks. Experience gained in this project places Japan District in a position to assist its partners in similar projects.
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