Tab Journal Winter 2013 - (Page 8)

Testing Issues with Temporary Flexible Ductwork Bryan Lacy, TBE Engineered Air Balance Co., Inc. D uring a recent project in a hospital facility, the team encountered several problems resulting from the initial design of the temporary ductwork being used. The project involved five existing AHUs located in a hospital basement that were selected for replacement. The five AHUs served different zones in the building, which was occupied at the time and had 11 levels. The initial project plan was to place a temporary AHU outside of the building in a nearby courtyard, run the temporary ductwork through a common outside air intake breezeway, and tie the temporary ductwork into the existing supply and return air ductwork until the permanent AHU installation was complete. The duct diagram below shows the sketch taken from the mechanical drawings indicating the return ductwork with eight round temporary ducts, and the supply with ten round temporary ducts. The unit was equipped with outside air louvers, and dampers were installed to assist in proportioning the quantities between return and outside air. The flexible ductwork was installed on both the supply and return air side of the temporary air handling unit, routed to a rigid piece of ductwork located on the roof (60”x60”x60’), and then back to the flexible ductwork down into the breezeway. At the breezeway, the flexible ductwork had another 400’ installed connecting to the existing ductwork taps for supply and return air. 8 TAB Journal

Table of Contents for the Digital Edition of Tab Journal Winter 2013

Tab Journal Winter 2013