Large Machine, Small Opening: Complex AHU Project Requires Disassembly, Reassembly
Installing an air handling unit is never a simple undertaking. But on a AHU replacement project at a prominent New Jersey university, PJM was faced with an exceptional challenge in that access to the building was limited to a 6’ x 6’8” doorway. Creating new or enlarging existing openings was not an option, necessitating the intricate and difficult task of disassembling the massive 45,000 CFM unit and reassembling it in place. To further complicate matters, time was of the essence to complete the project in order to minimize interruption to the building’s critical daily operations.
The AHU was delivered in four sections – a mixing box, an energy recovery wheel, a fan section and a steam coil section – and each was promptly disassembled. Hundreds of parts including nuts, bolts, frames, panels, coils, fans, etc., were carefully match-marked and palletized, and each step of the process was meticulously recorded to guide reassembly. Using an emission-free electric forklift, the parts and pallets were maneuvered through the opening in the sequence in which they would be reassembled with as little as ½-inch clearance. The large energy recovery wheel module posed a particular challenge in that the wheel itself had to remain intact, so a special cradle was devised to move it into the building on an angle.
Even as PJM mechanics were still disassembling, packing and moving the various AHU
components, other team members were methodically assembling sections in place, beginning with the outdoor air section. Through experience, skill and ingenuity, PJM successfully assembled, inspected, tested, and started the new air handling unit in just three days, much to the appreciation of the university.
PJM Mechanical Contractors, Inc. is a multi-faceted mechanical contractor providing construction and installation, service and maintenance, and design/build services in a comprehensive range of mechanical disciplines that include HVAC, plumbing, controls, refrigeration, custom metal fabrication, piping, fire protection, and backflow preventer testing. PJM primarily serves clients in pharmaceuticals, manufacturing, healthcare, institutional, and other various commercial and industrial sectors.