...Corrado and Fishking had been exploring prefab racks. “We all remember the meeting because we had this simultaneous ‘a-ha’ moment,” says Fishking. Corrado adds, “It pretty much snowballed from there.”

At the time, Corrado had been checking into even more ambitious prefab work by his Skanska counterparts in Europe. Fishking initially had been intrigued by a photo he had seen of a prefabbed overhead rack, minus the drywall, for the St. Clare Health Center near St. Louis, completed in 2009 by Alberici Constructors.

The MVH prefab trip was not without bumps; there were naysayers, even within Skanska. “The pioneer is the guy with all the arrows in his back,” Corrado says. “No one wants to follow him, but they shoot at him,” he adds.

To get up to speed, Corrado made two trips to London to observe a Skanska prefab operation under way there. The first trip was with Scott Hansma, Skanska’s MEP superintendent. The second trip was with representatives of TP and Chapel and MVH’s Eling. That “sealed the deal” with the owner, says Corrado.

Eling, who became a fan of prefab, adds, “We said, ‘If the budget and schedule are not going to change, go ahead.’ ”

Prefab in London, where craftworkers are under one employer’s roof, is one thing. Prefab in the U.S. meant dealing with union and open-shop contractors working side by side, says Corrado.

Tasks all got sorted out. “The [union] electricians were OK working with an open-shop contractor,” he says.

“We learned how to work better with MEP contractors,” adds Dayton’s Coyle.

Key to the success of the strategy was the use of building information modeling. For the work, there were separate design and construction BIMs. “Using 3D layout during design” aided the modeling of the whole assembly, says Brian Braaksma, president of Korda Engineering, the Columbus-based MEP consultant.

Full-scale physical mock-ups of patient rooms and racks, for bidding purposes, were also critical to success. Built on the hospital campus, mock-ups also allowed end-users to give input and regulatory agencies to grasp the approach.

“We don’t usually mock up corridor utilities,” says NBBJ’s Fishking.

Mock-ups were detailed down to electrical outlet locations because, once the model was set, all 178 rooms would be done the same way. To establish the final design, users even did simulations of patient and caregiver conditions.

The addition has five patient-room floors. Each floor has three wings. Each wing contains a single-loaded, 16-ft-wide corridor with 11 “same-handed” rooms, rather than pairs of mirror-image rooms. The same-handed rooms were designed to accommodate the need for repetition on the “assembly line.” Two, 8-ft-wide corridor racks, each 20 ft long, are positioned side by side, running the corridor’s length.

Braaksma says the racks serve double duty: Mechanical and electrical supports serve as the building structure’s seismic restraint, required by code, and the rack’s frame serves as seismic restraint for ductwork, piping, conduit and cable trays.

The design significantly reduces clutter above the ceiling, which will aid hospital maintenance staff, says Braaksma, as will the consistent and repetitive location of subcomponents, such as valves, terminal boxes and cable trays, from area to area and floor to floor.

Foundation work started in May 2008. On June 1, worked stopped for 14 weeks because of the soil snag. The prefab operation got under way on Feb. 2, 2009, in 35,000 sq ft of space in a nearby warehouse. Leasing warehouse space in Dayton costs $2.00 to $2.50 per sq ft per year.

The original plan was for just-in-time delivery of prefab units to the site, three miles away. But instead of producing two to five racks per week, workers produced eight to 10. “We filled up the warehouse in six weeks with prefab for two hospital floors,” says Corrado.

Because of the foundation delay, the steel structure was not ready to receive units until mid-July 2009. To keep prefab production going, Skanska leased 70,000 sq ft in another warehouse three miles in the other direction from the jobsite.

In hindsight, to keep production from piling up, prefab work could have started in early March 2009. Without the schedule delay, installation could have started that June 1 and been completed by mid-August. Substantial completion of patient floors would have been at the end of last March instead of mid-July. Substantial completion of the rest of the hospital would have been by mid-June 2010, rather than mid-October. (Substantial completion actually has been pushed to December because of the foundation delay.)

At the jobsite, once concrete deck was cast and the drywall contractor had laid out and shot down the top track of all corridor walls, TP laid out and installed the clips that suspend the racks. Fireproofing followed.

Racks then were hauled from the warehouse on Saturdays the tower crane was available. It would typically take one day to haul and place on the floor a full level’s worth of racks. It would take about a week to a week and a half to hoist racks into final position and secure them.

Bathroom pods and head-wall units for that level followed on the next available Saturday, usually about two weeks later. Crews would spend the next work week distributing, leveling and attaching the pods and head-wall units to the floors. Once all the components were installed, crews began remaining rough-in work.

Saturday hoisting was mandatory because all prefab components had to be swung into the building via tower crane,...