UMEC: Heavy weight contractor for Herculean task

SolarThermal Oxidizer Overall photo
Final installation of ductwork 62 ft. above ground.

A project for Solar Turbines in San Diego required SMACNA contractor University Mechanical and Engineering Contractors, Inc. (UMEC), an EMCOR Company, of El Cajon, Calif., to do some seriously heavy lifting.

The contractor custom fabricated and installed 84-inch diameter, 110-foot-long, 304 stainless steel ductwork to divert smoky exhaust emitted during liquid fuel turbine engine testing on two combustion thermal oxidizers.

The system was engineered to sustain the extreme heat—between 1,700 and 1,800 degrees Fahrenheit—used to completely burn fuel and hydrocarbon residue produced during the testing process.

Welding pieces that form the elbow.
Welding pieces that form the elbow.

 UMEC spent thousands of hours on the project, which involved fabricating 42,000 pounds of ductwork and welding more than 10,000 inches of metal, including 5/8-, 1/2-, and 3/4-inch plate, 11-gage sheets, 5- x 1-inch flat bar, and 4- x 4- x 3/8-inch angle iron. There were four 90-degree elbows, which each required 13 pieces of sheet metal and weighed 4,000 pounds.

UMEC added six sheet metal plate saddles, weighing 800 pounds each, and 12 support bands, weighing 400 pounds each. To deal with the extreme heat, UMEC installed round expansion flex at each turn. Straight duct sections ranged from 8 to 10 feet long.

Performed final installation at 62 feet above the ground

Each 90-degree elbow weighed 4,000 lbs.
Each 90-degree elbow weighed 4,000 lbs.

Onsite installation included attaching the 84-inch diameter final piece of duct 62 feet above the ground to the exhaust diverter box, a 124- x 124- x 996-inch piece of duct with an attached 84-inch square-to-round adapter that weighed about 2,200 pounds.

It was not an easy job—no tolerance was allowed in the 90-degree angles and more than 2,000 5/8-inch round holes in companion flanges had to be made without a misalignment.

Even so, UMEC ended up with zero quality control issues and no rework required.

Ductwork installed was 84-in. diameter and 110-ft.-long.
Ductwork installed was 84-in. diameter and 110-ft.-long.

The customer, Solar Turbines, is a wholly owned subsidiary of Caterpillar Inc., with headquarters in San Diego. Solar Turbines’ products include gas turbine engines, gas compressors, and gas turbine-powered compressor sets, mechanical-drive packages and generator sets. Products from Solar Turbines play an important role in the development of oil, natural gas and power generation projects in some of the toughest, most challenging arctic, desert, tropical, and offshore environments. Solar’s fleet has grown to more than 15,000 units worldwide logging more than 2 billion hours in more than 100 countries.

UMEC was founded more than 90 years ago. The SMACNA contractor has offices in San Diego and Los Angeles, Calif., and provides design/build, design/assist, HVAC, plumbing, sheet metal, and process piping services for health care, biotech, water treatment, power generation and a wide range of other facilities.

Case Study Date: MAR 11, 2016