BIDMC New Inpatient Building Envelope Engineering

Local Fabrication
Over the course of the pandemic, construction on the Beth Israel Deaconess Medical Center New Inpatient Building (NIB) did not skip a beat. During that time, I had the opportunity to make regular visits to Ipswich Bay Glass (IBG), located in Rowley, MA. During the visits, PAYETTE and SGH envelope inspected the quality and sealing of the assemblies, confirmed finishes, documented stored materials and tracked the overall progress of the curtain wall and other exterior rainscreen systems.

The complex is comprised of seven warehouses (two of which are leased to other tenants) and houses equipment that can extrude curtain wall frames, form composite panels and glaze-in an array of panel types. And at any given time, the facility has an impressive capacity to manufacture, assemble and crate up to five large-scale projects. Notably, IBG has previously worked with PAYETTE on other projects including Boston University’s Rajen Kilachand Center for Integrated Life Sciences and Engineering and Tufts University’s Science and Engineering Complex.

IBG assembly line for BIDMC’s unitized curtain wall

Since December of 2020, IBG has dedicated four lines of production for the BIDMC project. Viracon glass is delivered to IBG’s facility and glazed into the assembled frames. Weather gaskets are left uncut until glass is set within the frame to create a complete seal. Jacks are placed below the glass to reduce oil canning when set within the frames. Inside corners of the assembled curtain wall frames are sealed to prevent air and moisture mitigation. Once assembled, the panels are clean and crated onto IBG’s trailers for transportation to the project site.

Performance & Design
In 2017, IBG, Turner Construction (TCCo), Simpson Gumpertz & Heger exteriors (SGH) and PAYETTE were involved in the design assist process for the exterior envelope system of the New Inpatient Building. The design assist process helped the design team ensure constructability for complex details by gaining a head start on shop drawings, informing design decisions and ultimately achieving a high-performance envelope to meet today’s demanding energy codes.

High reflective coated unitized curtain wall

The curtain wall of the patient tower is a four-sided structural sealant glazed (SSG), double-glazed curtain wall system (Kawneer 2500 PG). The design of the tower follows a series of vertical, highly reflective glass between piers of accented terracotta panels. The decision for a highly reflective coating was largely due to patient privacy and its low solar heat gain coefficient (SHGC) value. Aesthetically, the reflective coating toward the outer face of glass helps minimize the typical registration of vision to spandrel glazing and keeps the viewer’s on the profiled terracotta panels.

To design a high-performance envelope, the curtain wall is further supplemented with a perimeter radiant heating system, installed at the head of each window, and further enhanced with a continuous layer of foil faced mineral wool insulation. As energy codes tighten, it is likely that the industry will see more curtain wall assemblies adopt this method of construction.

The Engineering & Installation
The engineering behind the NIB’s exterior system was not without its challenges and hurdles. The above average floor-to-floor heights of the new tower warranted a solution for the increased spans of the curtain wall system. IBG has engineered the curtain wall mullions with internal reinforcement, in order to minimize the amount of structural steel and visible horizontal mullions. These continuous HSS1X1 members are set within the curtain wall frames, thereby increasing the acceptable span and lateral resistance of the system.

Video of unitized panel installation

On average, IBG installs eight panels per day on site. Curtain wall end dams are factory-attached to the vertical mullions to create a seal at the stack joints. A boot, consisting of high strength silicone sheet, is then sealed over the aluminum end dams to create a full seal at the stack joint.

Overall image of current work

As of this spring, the unitized curtain wall for the job has been completed. Over 90% of the system is installed on site and work on the rainscreen backup wall, stick-built curtain wall, and louver systems are underway. The quality of the glazing has been noted by many on the project and the general public and serves as a testament to the hard work and design executed by the project team.

The project is slated to open in the spring of 2023. Stay tuned for future updates!