Design/Build Awards: Design/Build to the Rescue

Design/Build Awards: Design/Build to the Rescue

When the bell rings at South End School, students study in comfort, thanks to Harrington Engineering.

It’s no secret to anyone in any of the construction related fields that even the best-run projects can become complicated. And if a talented Design/Builder can step in like a superhero and make things simpler when complications begin to rear their ugly heads, everyone involved benefits.

The team at Harrington Engineering, Old Saybrook, CT, probably doesn’t think of themselves as superheroes. However, when it came to their work at the South End Elementary School in Bridgeport, CT, they were at the very least the great simplifiers.

The complications at the South End Elementary School project were political as well as mechanical. A vacant University of Bridgeport dormitory building was being converted to “swing space” to be used by students of the Bridgeport Public School System as other buildings in the district underwent renovation. This meant that while the general contractor, Downes Construction Co., was working for the University of Bridgeport, the university was under contract to turn the completed building over to the city.

“The university had a contractual agreement with the city, we had a contractual agreement with the university, and so we got tied into the university’s agreement with the city,” says Paul Wojtowicz, Downes Construction Co.’s project executive. “That arrangement created some bumps in the road. We weren’t contracted to the city, but nevertheless the city was the one buying the job.”

When Harrington Engineering, perhaps intrigued by a challenge, approached Downes Construction about this project, they found that Downes had already published individual requests for proposals for the mechanical, electrical, plumbing (MEP), and fire protection trades. It was time for Harrington Engineering to step into a phone booth and change into their superhero capes.

“As a one-source provider of mechanical, electrical, plumbing, and fire suppression services, we were able to offer the ability to streamline the building delivery process and provide innovative and integrated solutions without change orders,” says Daniel Wilkie, Harrington Engineering’s president and owner. “Downes Construction understood that Harrington Engineering’s collaborative team of professional engineers, designers, and field operations personnel would be uniquely able to resolve the various building code concerns and meet the objectives of the owner’s specifications using the existing limited space that was available.”

Once Harrington was on the scene, Downes Construction withdrew its RFPs from the market, and awarded Harrington the Design/Build privileges for the MEP and fire suppression systems.

“Finding one company that was able to pick up all of those systems with one contract helped very much with the design process and the coordination of the project,” says Wojtowicz. “It really expedited everything, because we didn’t have to wait for four different design engineers to design all those systems and then put them out to bid.”

In a case of being careful what you wish for, Harrington now had to adhere to the Bureau of School Facilities’ code standards to attain state funding for the project, and also satisfy the requirements of the ultimate purchaser of the building, the City of Bridgeport.

Challenges, Dilemmas, and Low Ceilings
From a mechanical systems standpoint, the most obvious challenge that faced Harrington Engineering was that all of the systems that Harrington was charged with renovating were in violation of the Bureau of School Facilities’ code standards, and traditional solutions were not viable because of the tight 9-ft. 6-in. floor-to-floor heights.

In addition, the building is located less than half a mile from Long Island Sound, meaning the high humidity levels posed a serious indoor air quality dilemma.

Thanks to the ever-increasing cost of energy, conservation was also a priority for the school district and the city. And, just to make things interesting, the construction schedule was extremely compressed. Although the project originally had an 18-month construction schedule, remediation and demolition of the existing systems meant that Harrington had only 10 months to complete the installation and commissioning of their MEP and fire suppression systems.

Harrington Engineering’s team of engineers, designers, and draftsmen understood that the cast-in-place concrete construction of the building would require all of its systems to be engineered around the existing structure. As a single-source provider for these systems, Harrington was able to produce a set of highly coordinated drawings to avoid the need for change orders or construction delays.

“The variable air volume systems specified in the RFP couldn’t fit in the space available above the ceiling, so the design team proposed a four-pipe fan coil system to condition the facility,” says Ken Hipsky, Harrington Engineering’s senior mechanical engineer. “The limited space above the ceiling also meant that lighting fixture placement would have to coordinate precisely with ductwork and piping to avoid collisions.”

Three Major Goals
Harrington Engineering’s three major goals for the South End School were comfort, safety, and energy savings. Fan coil units in each room were engineered to achieve the comfort goal by allowing for individual temperature control. To meet the goal of providing a safe environment, a gas-powered back-up generator system was designed to ensure that the lighting, heating, telephone, security, and fire suppression systems would operate in the event of an emergency.

Multiple aspects of Harrington’s designs were targeted to save energy. First, Harrington engineered an ice storage system that would allow the chiller to run at night, sending chilled water to seven storage tanks that produce ice for daytime cooling. This reduces the amount of peak energy consumed by the facility during the day.

The HVAC system is designed to use 100% outdoor air that is pre-conditioned by passing through an energy recovery ventilator on its way into the building. Occupancy sensors for the demand control ventilation system keep unused space minimally conditioned, and lights off until needed. In addition to its role in energy savings, the controlled ventilation system also mitigates humidity issues that would arise from over-ventilating the facility.

Finally, a dual-fuel system was engineered to allow the school the flexibility to operate on either natural gas or oil, depending on current market prices and availability.

Harrington Engineering’s design team added value to the project through its electrical design as well. To minimize the size of the generator needed to provide emergency power to the facility, a series of six automatic transfer switches were engineered to connect the load in a stepped fashion, gradually increasing until all emergency loads were transferred. In addition, a short circuit analysis and coordination study demonstrated to the owner the sequence in which the breakers would trip in case of a short circuit anywhere in the system. This helps prevent the main breaker from tripping prematurely and causing loss of power.

Commissioning and Turn-over

Commissioning and turn-over to the owner presented an issue on this project.

“Typically, a second-party architect and engineer work on behalf of an owner to verify that field installations meet all requirements,” says Charlie Juhasz, project manager for Harrington Engineering. However, thanks to the project’s complex contractual relationships, that wasn’t the case at the South End School. “So, we put together a conformance sheet for every room in the building,” Juhasz explains. “The sheets listed the components unique to each room, and our designers and engineers verified compliance to design on a roomby- room basis.”

To deliver added value, Harrington provided equipment start-up forms for every piece of equipment in the school.

“Working with Harrington Engineering was a very good experience,” says Downes Construction’s Wojtowicz. “It was an interesting Design/Build project with a total contract value in excess of $8 million, and they did a very professional job in all aspects. That was the first job we’ve done with them, but we’ve worked with them since then, and we look forward to doing a lot more with them.”

Are Harrington Engineering’s people superheroes? Maybe. Do they represent an outstanding example of what a versatile Design/Build contractor can accomplish? Absolutely.

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