A B&K team spent one summer switching out massive 55,000-CFM air handling units in a busy metropolitan hospital that was in full operation. The project (for Wellstar Kennestone Hospital in Kennesaw, Ga.) involved deconstructing the units offsite, transporting them to a staging site on the roof, then moving them to the fixed-footprint space inside a patient tower for reassembly. The choreography involved working around ambulances and helicopters arriving at the hospital – sometimes with no more notice than the sound of approaching vehicles.
B&K Project Manager Lance Boling takes us back to the time, when we replaced a pair of 55,000-CFM air handling units at Wellstar Kennestone Hospital outside of Atlanta.
Installed in 1974, the two units served five floors of the hospital’s Green Tower – and switching them out was no easy task.
How did you replace something so big without affecting air flow inside a working hospital?
We came up with a plan to build a customized air handling unit that could temporarily cover for one of the old ones while we replaced it. I say custom because we had a specific footprint to work with, and very limited space. All of the units were in this giant mechanical room on the third floor of the tower. The two we were replacing served five floors of the tower.
So what’s involved in adding a big temporary unit to a limited space?
Well, the same process applied to the temporary unit and the two permanent AHUs we were installing. They were way too big to just move into the room. In fact, even the basic segments or sections were too big to fit inside a door.
So, we had to break each unit down to component pieces – the floor, wall and roof segments, the coil sections, the fan cubes. The units came assembled and we went to a warehouse at T&D Machine Handling, and we broke down each unit into component pieces. We palletized these and lifted them up with a crane, then reassembled inside the space. It was like an erector set.
Of course, the temporary unit had to come first.
That’s right. We did custom-built Temtrol units, and for the temporary one, we ran temporary ducts and 6-inch chilled water pipes from it to the unit being replaced at the time. We first removed another unit that wasn’t in use.
What was involved with lifting the palletized components to the space?
That was a huge part of the project. Obviously, we used a crane, but there was a lot to think through. It was a 240-ton crane, and the only place to set it for the job was at the main ambulance entrance to the Emergency Department.
We would drive it to a space behind the hospital on Friday evening. Early Saturday morning, we set out signs and cones everywhere, so that ambulances would know what path to take. They would use an alternative ER entrance during the weekend.
Beyond figuring out the logistics, what else had to be done?
Communication was everything. All the different ambulance services and 911 operators had to know what was going on. We even rented flashing message signs to make sure drivers saw them.
Another thing to think through was the hospital helipad. Every time a patient was flown in, we had to retract the boom of the crane. Most of the time, the life flight operator would call to say we’re x many minutes away. But some flights came in hot. You’d hear the helicopter blades in the distance, and you knew we had three or four minutes to move everything.
You said the mechanical room was huge – big enough to do all the work?
Well, it was big, but tightly packed, so no. But outside the mechanical area was a roof, so we built a 60-foot by 60-foot deck to store both the demolished material and the new components for the units.
But we had to strap everything down on this deck because of the helicopters. The blades produce air shooting down to the helipad, then laterally. It’s a lot of wind, so if we didn’t tie it all down, some materials would’ve blown off the roof.
How many weekends of lifts were required?
All in all, seven. We did it all in stages, and each day was a 12- to 14-hour day. The first couple of weekends were a little nerve-wracking because it was the first time we’d done something quite like that. We’ve had lifts in tight situations, but coordinating with ER service, police, traffic, ambulance service – that was new.
Was that the hardest part of this job?
I think so. The intense level of coordination that was required – for crane lift, shutdowns, getting the timing right for all of them. Everything would have to be planned out far enough in advance to coordinate with everyone. Of course, we always have a lot of coordination with hospital staff like nurse floor managers, department heads and heads of labs. But in this case, for the whole Green Tower, our work impacted about 25 percent of the entire hospital. That’s a lot to coordinate.
One lasting value we created – the custom-built Temtrol AHU that provided temporary air handling while we built and replaced the two large AHUs ended up being a permanent replacement for another unit.
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