NOTE: A condensed version of this article has been published in the February 2021 issue of High Profile, here: Sustaining the Future by Revisiting our Historic Properties - High-Profile Monthly
Jones Library in Amherst, Massachusetts—designed by Putnam & Cox in 1928—was originally built to look like a residence, with its robust stone facade and distinctive gambrel roofline. This initial vision for the library was prophetic, for over the years Jones Library has become a true home for this passionate community of thinkers and learners in the Pioneer Valley. The Town of Amherst and the Library’s Building Committee hired Finegold Alexander Architects to help shepherd the beloved but now outdated and undersized facility into its next century of service. Front and center in this endeavor are issues of sustainability: what strategies can be used to reduce levels of energy consumption of the existing historic building, and can a new addition be designed in a way that will minimize the environmental impact of an expanded facility?
Finegold Alexander’s design proposes a comprehensive renovation of the existing historic building and a three-story addition to rear. The expanded library will meet contemporary needs, addressing accessibility issues while introducing upgrades to security, the HVAC system, and technology. While the project is in the schematic design stage, the Jones Library Sustainability Committee tasked Finegold Alexander with reviewing possibilities to greatly reduce the library’s environmental impact by creating a low carbon project. This involved examining energy and operational carbon use as well as the embodied carbon of the building’s materials and construction. To this end, detailed energy modeling was conducted and a full life-cycle assessment was completed with Tally software.
The findings enumerated in the team’s Sustainability Goals Schematic Design Report for the Jones Library design provide a baseline for informing future design decisions. Some of the report’s findings are presented below.
EUI Goal/Net Zero
As shown in the graphic below, the current site energy use intensity (EUI) of the existing Jones Library building is 73.2 kBtu/sf/year. The Median site EUI for library buildings in the United States as listed by the 2012 Commercial Building Energy Consumption Survey (CBECS) is 71.6 kBtu/sf/year.
An analysis of the proposed design—based off the schematic energy model—indicates a predicted Energy Use Intensity (pEUI) of 34.4 kBtu/sf/year, showing a 52% decrease in energy usage over the median site EUI for library buildings. The pEUI does not assume the use of any on site renewable energy sources which could further decrease the EUI.
Energy Conservation Measures (ECMs)
A series of ECMs were developed by the design team to further decrease the site EUI of the Jones Library renovation. With the implementation of selected ECM’s, Net-Zero Energy could be achieved through purchased off-site renewable energy.
Eliminate Use of Fossil Fuels
The existing building is serviced by natural gas that is powering the heating boilers and hot water heater. The proposed design eliminates all gas-powered systems and replaces them with systems that are powered by electricity, including a proposed high efficiency VRF system for space conditioning. The use of geo-thermal wells was also examined as a means of driving energy use lower, while supporting the all-electric design.
Low Embodied Carbon Materials
The feasibility study and the revised schematic design focused on a conventional steel framed structural system that consisted of a composite concrete and metal deck slab on a structural steel column and beam system. In the interest of pursuing a building with low embodied carbon materials, we worked with our structural engineer (RSE Associates, Inc.) to prepare a schematic package with an alternative heavy timber hybrid structural system. The alternative proposes maintaining a conventional steel column system in the basement and a heavy timber structural system on the upper floors.
The heavy timber system consists of cross-laminated timber (CLT) floor slabs on glue laminated (glulam) columns and beams. The design team performed a comparative Life Cycle Assessment that examined the environmental impact of the structural systems. The results showed that the timber structure resulted in significantly less Global Warming Potential than the steel structure.
A cost estimate completed for the hybrid system did show a significant first cost increase. The system and all building materials will be further refined throughout the design process to produce the best balance between available budget and the library’s sustainability goals.
Whole Building Life Cycle Assessment
Whole Building Life Cycle Assessment (LCA) is the most widely accepted method for assessing embodied carbon. In addition to exploring alternative structural systems to reduce the embodied carbon of the new addition, the design team has prepared a Whole Building Life Cycle Assessment that explores the embodied carbon of the proposed addition. This number is listed as Global Warming Potential and the results are expanded upon in the bar chart. The design team is prepared to continue to work towards lowering the embodied carbon of the building with comparative analyses in subsequent phases.
The Life Cycle Assessment (LCA) for Jones Library was performed using the Tally Life Cycle Assessment software. The scope of the assessment includes core, shell, footings, foundations, structural wall assemblies from cladding to interior finishes, structural floors and ceilings, interior non-structural walls and finishes, and finishes on structural floors and ceilings for the new addition and the existing portion that will remain. The assessment found that, among other environmental impacts, the materials and construction of the proposed design embodied carbon was:
This is equivalent to the CO2 emissions from the energy use of 165 typical homes in one year. This number is based on the schematic design and should be considered a baseline. To gain a fuller understanding of the impact of the new work being performed, the design team also produced a LCA that evaluated the new addition alone. This report found the new addition embodied carbon was:
1,274,228 kg CO2eq.
The environmental impacts as quantified by the impact categories in the LCA can be improved through various measures such as adding fly ash to the concrete and reducing material usage throughout the design. The design team will continue to work with the Library and Sustainability Committee to assess potential design alternatives relative to their impact on embodied carbon.
While the above numbers might suggest that the proposed construction will result in greater environmental impact than a “build nothing” and attempt to live with what you have option, operational energy use of the library must also be considered. Based on the current EUI of the existing building (73.2 kBtu/sf/year) and assuming 22% of that energy is heating from natural gas, over 60 years the Global Warming Potential is 18,288,925 kgCO2eq, or the equivalent of 2,110 homes’ energy use for one year. In contrast, the study showed that the proposed design has an operational carbon use of 11,382,681 kgCO2eq or the equivalent of 1,313 homes’ energy use in one year, or a 38% reduction in operational carbon over the existing facility. This demonstrates that careful planning can provide for a public library that meets the needs of today’s citizens, while preserving our planet for the generations of users to come.
Thank you to the dedicated and visionary members of the Jones Library Building Committee and the Jones Library Sustainability Committee.
Thank you to the consultants contributing to the Jones Library Sustainability Goals Schematic Design Report, Including:
Structural: RSE Associates, Inc.
MEP: BLW Engineers, Inc.
EUI report and energy modeling: Andelman and Lelek Engineering, Inc.
Cost Estimating: Fennessy Consulting Services
Thank you to the Jones Library project team at Finegold Alexander:
Principals in Charge: James Alexander, FAIA, LEED AP and Ellen Anselone, AIA, LEED AP BD+C
Design Principal: Tony Hsiao, AIA, LEED AP
Project Manager: Josephine Penta, AIA, LEED AP BD+C
Project Architect: Beth Pearcy, AIA, LEED AP BD+C