California State University, Long Beach Liberal Arts Buildings Renovation Project
The renovation of three buildings at CSU Long Beach has created updated teaching facilities and outdoor spaces for faculty and students, while greatly improving seismic, lighting and HVAC systems. The three buildings — Liberal Arts 2, 3 and 4 — house offices and 26 classrooms, and enclose a series of outdoor spaces that were also updated during the renovation.
The geometry of the 1950s-era buildings had good potential, with large windows mostly facing north for daylight with minimal solar gain, and well-shaded transom windows facing external circulation corridors. In the initial planning of the project, staff from Physical Planning and Facilities Management determined that retaining the existing buildings would be a sustainable and cost effective solution, reducing the amount of demolition debris produced and raw materials required.
This project represents common California campus buildings from the 1950s, with “good bones” but in dire need of new sustainable building systems and contemporary teaching technology.
In the renovation, the envelope was thoroughly upgraded, and the roof, walls, windows and doors were replaced with energy efficient products. The walls and roof were insulated to meet Title-24 prescriptive standards, which are more stringent than most performance-based requirements. Batt insulation between framing is supplemented with continuous insulation outside of the framing to prevent thermal bridging through studs. The roof upgrade includes continuous rigid insulation, and single-pane windows were updated with contemporary dual-pane tinted glazing.
Updated classrooms provide active-learning spaces that feature current technology.
The improved envelope allows for a smaller HVAC system, and economizer cooling with up to 100 percent outside air is sufficient during much of the year in the campus’s coastal climate, until the outdoor temperature reaches 70°F. The HVAC system is further controlled by occupancy sensors (included as part of the lighting control system) at the level of each zone, so that rooms can go into standby mode when unoccupied. The system also integrates demand-based ventilation using CO2 sensors in the rooms. All lighting was upgraded to LEDs, with dimming controls for perimeter areas and occupancy sensing throughout. Combined these strategies yield 33 percent energy savings compared to the Title-24 baseline.
This efficient envelope enabled the use of a mixed-mode conditioning system that relies on operable windows for natural ventilation, supplemented with user-controlled ceiling fans throughout most of the building. For heating, central-plant steam is converted to hot water and piped to perimeter radiators. These strategies reduced the mechanical ventilation system by approximately 50 percent, compared to conventional design without natural ventilation. A west-facing stair tower was designed to act as a thermal chimney to provide ventilation and avoid the need for mechanical cooling. The laboratory exhaust system is informed by an anemometer at roof level, so that exhaust velocity can be reduced to save energy when wind conditions are favorable.
Classroom layouts take advantage of the buildings' solar orientation.
A key part of the renovation was the redesign of three courtyards formed by the buildings. Previously consisting mostly of turf, the new landscape design includes hardscapes with trees and furniture that can be used for socializing, relaxing or studying between classes. The new design also improves circulation around and between buildings, and is expected to reduce irrigation water use by over 50 percent.
Seismic improvements include the addition of new concrete shear walls on transverse walls, new footings and strengthening of the roof and openings. Together these upgrades now provide the campus with safe and contemporary active-learning spaces with state-of-the-art technology to meet today’s classroom needs. Going forward, the campus is evaluating the possibility of programming the new control system to provide demand-response capability by triggering preset lighting reductions and increased temperature setpoints.