MedImmune Childcare Center
MedImmune Childcare Center
One MedImmune Way
General Contractor: DPR Construction
Engineer/Architect: Reese Engineering, Inc.
Architect: StudioMLA Architects
Contract Amount: $2,029,711
Start Date: 8/2/16
Completion Date: 5/31/17
MedImmune, the global biologics research and development arm of worldwide biopharma giant AstraZeneca, is headquartered in Gaithersburg, MD. Adjacent to the MedImmune campus, a new childcare facility for MedImmune and AstraZeneca employees was under construction. Shapiro & Duncan’s scope of work included construction of the center’s mechanical and plumbing systems.
The building is a two-story radius structure, in the shape of a half-circle. In addition to having curved walls all the way around, the structure is built into the side of a hill and is partially below grade. This raised both design and installation challenges:
- First, from a design standpoint, a minimalist mechanical system would be required. Due to high exposed ceilings used to create an open interior aesthetic, there would not be room for a typical HVAC system. We would have to deal with reduced ceiling space in which to conceal mechanical and plumbing components.
- Second, piping installation inside this curved C-shaped building would be complicated. To make the curve, piping joints would be needed every few feet. This would require our welding crews to be more thoughtful than usual about welding pipe and adjusting it to the angle of the fittings.
- Third, because there isn’t enough space for a typical ceiling-mounted HVAC system, the project engineer decided to install a geothermal radiant slab heating system that is not commonly seen in the United States. Inside the concrete slab are hundreds of feet of plastic tubing, zigzagging back and forth. From the pipe, manifold pumps circulate hot or cold water into this network of tubing and the warmth or chill coming off the slab tempers the room. The result is less visible piping and ductwork as well as a reduced amount of mechanical equipment.
While the unique radiant heating system provided a great solution to the lack of concealed space for a typical HVAC system, it created significant challenges when it came to installing plumbing equipment. It should be noted here that the manifold and tubing were engineered under a separate contract, and installation of the embedded tubing was overseen by the project engineer. Once that tubing was embedded in the concrete, our team would have to deal with the on-the-job challenge of locating fasteners for toilets, sinks and other plumbing components. In order to drive fasteners into the concrete, we would need to know the exact location of the tubing before we set toilets and sinks.
- Lastly, another installation challenge was created by the fact that the underground piping on the site had been installed by another contractor who was terminated. After we took over this portion of the job, we would need to do a survey of everything the previous contractor had roughed in to make sure it would coordinate with our work.
Based on previous experience and proven process, the first step we took was to map out everything that had already been installed, so that this information could be used in the coordination process. Our computer-assisted design (CAD) team, which operates our cutting-edge building information modeling (BIM) system, sent out surveyors with digital scanners to scan locations where piping had already been roughed-in. Once the CAD team had these images, they were able to produce 3D models coordinating piping and ductwork with the other trades.
While this was not a contract requirement, Shapiro & Duncan uses 3D modeling as our standard because we have found when ceiling space is tight, there is no substitute for coordinating with other trades to avoid mechanical conflicts. On this project, we even convinced the other trades to use 3D modeling so that we would all be working off the same coordinated drawings. In hindsight, if we hadn’t gotten the other subs on board with 3D modeling, there probably wouldn’t have been enough ceiling space in which to fit all of the building’s mechanical, plumbing and utility services.
Prefabrication is usually a key part of a Shapiro & Duncan mechanical solution. On this project, this proved to be the case as our 51,000-square-foot prefabrication facility in Landover, MD, was able to prefab piping in the very tight mechanical room as well as the mains that run down the corridors. These are large pipes that run down the length of the long, curving corridor, “ducking and dodging” around the other trades. Here, 3D modeling was essential yet again in coordinating layout of these mains with the other trades to avoid conflicts.
Speaking of coordination, getting all of the trades on board required a considerable amount of pre-thought since we were dealing with concrete slabs that couldn’t be punctured as well as radius walls. Our job foreman pushed for GPR scanning and he worked closely with the other contractor’s team putting tubing into the slab. To say that the outcome of our solution depended on a high degree of effective digital and face-to-face coordination is an understatement!
Elements of our mechanical and plumbing solution include:
- The full building radiant slab system using geothermal wells (installed by other contractors).
- Three heat pump heat exchangers with two air handlers for fresh air intake and humidity control, plus a number of fans and unit heaters throughout the building.
- Plumbing system with a mixture of sink and bathroom fixture types and sizes for children and adults, a grey water system which uses rainwater for toilet flushing, and components for a food service kitchen.
A radius building with radiant heating/cooling, a geothermal field and a rainwater harvesting system isn’t a common occurrence and presents a number of unique and rarely encountered design and installation challenges. Where other contractors may shy away from potentially risky projects like this one, Shapiro & Duncan is willing to take them on and use our team’s skills, technologies and experience to make them a success.
Teamwork was a huge key to our success. Our foreman and field management team stayed focused on the job being a success for everyone. They were actively involved in daily planning and sequencing with the trades as well as on-the-job coordination with the general contractor. They were open in communicating how all of us could work together to avoid issues and plan ahead with each other in mind.
Our team spearheaded 3D coordination and invited other trades to join in. This was critically important in ensuring that all systems could be installed with little to no conflicts. All of the trades benefited from this group effort. We commend them for their willingness to try, and their ability to succeed with new technologies. Once all of us got over the initial hurdles of designing, engineering and installing an irregular system, it was a painless experience.
The job ended on a successful note, in large part thanks to the positive relationships our team succeeded in establishing with staffs of both the engineer and general contractor. There have been few, if any, operational problems. Shapiro & Duncan has been rewarded for our reliability by being awarded the maintenance contract with the owner to maintain the equipment moving forward.