Bridging the Gap Between Design & Construction: Scott Guertin's Expertise Shines in Successful AHU Replacement Project at Boston Children's Hospital

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

Wise Construction is no stranger to major mechanical upgrades, especially in a fully operational hospital environment. It not only requires expert knowledge of healthcare construction but also understanding the hospital, as well as its users, and being able to work together with a team of skilled trades and project partners to get the job done right. When the project involves particularly complex mechanical systems, Wise’s Director of Engineering, Scott Guertin, steps in to bridge the gap between design and construction.

When Boston Children’s Hospital’s engineering team approached Wise about the highly complex replacement of two stick-built interior 65,000 CFM Air Handling Units (AHUs) and one 100,000 CFM Return Fan (RF) serving patient and clinical floors, they knew they could trust us to complete the tasks on time—each with a condensed 45-day schedule.

Scott’s approach was simple: find the most efficient construction paths. Due to the proximity of other mechanical equipment, including ten other operating AHUs in the fourth-floor mechanical room, specific design and building considerations were necessary. This included procuring custom AHUs, ensuring minimal disruptions to ongoing patient care below, designing temporary air solutions for patient floors and active renovation projects above, and building these units to last.

The first step was procuring the AHUs from Cambridgeport Custom, a local HVAC company. “Sourcing a custom AHU locally, obviously saves time, and having a first-rate engineering team is paramount,” says Scott. “Cambridgeport’s Rumen Raykov, whom I have worked with for years, doesn’t just design units from his desk; he visits the site, takes measurements, ensures everything fits perfectly, and stands by his work. With these units being super custom—the second one had to be designed around existing structural columns—his willingness to meet me on site whenever I needed him made it significantly easier to integrate the new systems seamlessly.”

Though saving time was our goal, our priority was ensuring zero disruptions to the active patient floors. Operating rooms are located directly beneath the mechanical room, so we couldn’t make any noise or vibrations during times the space was being utilized. “Constructing the first unit was more challenging than the second because we had no idea what was beneath the slab,” Scott reflects. “The way the slab was built beneath the original unit prevented us from seeing what was underneath until we demoed the unit and chipped up the concrete slab. We had limited time to decide what to do, so the demoing and chipping were completed on a Saturday and Sunday. During that weekend, we discovered that the floor was uneven, requiring quick decision-making to chip up and re-pour a new, level pad in just two days.” Applying this knowledge to complete the second unit quickly with no disruptions to active surgeries below, our team and trade partners worked 24-hour shifts on the weekends.

Designing temporary air solutions to feed the active renovation projects being worked on by a different contractor, while adjacent space was fully occupied, was another challenge. A continuous and reliable air supply for both spaces was required. Fortunately, AHUs 1, 2, 3, and 4 were all cross-connected. As we replaced units 3 and 4, we could supplement with neighboring units 1 and 2. “We had to figure out how to back-feed air to various units while maintaining the system’s integrity. We removed the existing access doors to the fire dampers and used them to tie into the risers. This allowed us to maintain airflow, while we cut the bottom of the risers and created a temporary duct system, until the units were finished,” Scott notes. This also meant completing sections of the unit out of order. As we provided temporary airflow to the risers, recognizing that it wouldn’t suffice once the project was handed over, we prioritized completing the supply plenum section of the unit to meet the needs of the other contractor’s project, which we delivered on time.

The new units are designed and built to last. “We poured a new pad and then epoxied the floor, creating a waterproofing membrane to mitigate any water leakage issues. The floor is diamond-plated with welded seams, and the lips of the perimeter are turned up like a bathtub. This design feature addresses potential water leakage issues as water would have to fill up to at least two or three inches before it would start leaking out. Furthermore, the units are lifted off the floor on base rails to provide a view beneath the unit, which you couldn’t do before,” says Scott.

He continues, “Another issue with the old units was that they were each powered by one giant fan. If that fan failed, so did the entire unit. We designed the new units to have a fan wall—a wall of smaller fans that spin simultaneously. This redundancy means that if any one fan fails, the rest speed up and carry the load. All of these updates make maintenance much easier for the hospital’s facilities team.”

Lessons learned from the first unit were applied to the second, streamlining the design and construction process further. “After completing the first unit, we brought the trade and project partners together into a meeting to discuss how we could improve for the second unit. This collaborative approach ensured that the second unit was completed even more efficiently,” Scott notes.

Central to the success of these challenges and to achieving the accelerated 45-day schedule per unit was the collaborative effort between Wise Construction and our project partners. “I was essentially another set of eyes on site while also being an extension of the design team,” Scott says. “Our trade partners who worked day and night to achieve this near-impossible schedule. Their tireless efforts and expertise were the true reason for this project’s success.”

Project Partners:

Client: Boston Children’s Hospital

Engineer: BR+A Consulting Engineers

Demolition: Unified Construction Group

Pad install (flooring): Pavilion Floors, Inc., A Diverzify Company

Electrical: Murphy Electric & Industrial Control, LLC

Controls: ENE Systems

Pipe, Duct, AHU Build: Cox Engineering

AHU Manufacturer: Cambridgeport Custom

Commissioning: Environmental Health & Engineering

Wise Project Team:

Superintendent: Daniel Iwano