The TVA Bull Run Fossil Fuel Plant in Clinton, Tennessee, needed a final design for all new exhaust ductwork for two existing auxiliary boilers, but there was an unusual element to the job: the design of the duct sections needed to be based on a specific sequence of construction. IDI was asked to determine the duct plate thickness and stiffener requirements and the final support trapeze and rod sizes; analyze the supports for the static load and thermal growth to verify the support system design and expansion joint capacity; and provide all duct assembly/erection connection details and welding requirements.

And due to limited space within the facility, the duct sections had to be installed in a particular order. As such, IDI worked with the contractor to determine the sequence then coordinated our drawing release to the fabricator so that the duct sections could be shipped to the site in that order. The fast-paced nature of the project meant drawings were submitted within 2 weeks and any design, fabrication, or construction revisions were addressed immediately.

Specifications:

· Design temperature = 1,000 deg F

· Design Pressure = -5/+15 w.c.

· Determine the duct plate thickness and stiffener requirements.

· Determine the final support trapeze and rod sizes plus the system bracing requirements.

· Analyze the supports for the static load and thermal growth to verify the support system design and expansion joint capacity.

· Insulation design to provide temperature of 140 deg F on outer surface of lagging.

· Insulation/lagging connection details.

· All duct assembly/erection connection details and welding requirements.

· Access door framing and connection details.