STV: Mother Clara Hale Bus Depot

Existing building retrofit of a transportation terminal

By STV August 17, 2015

Engineering firm: STV
2015 MEP Giants rank: 39
Project: Mother Clara Hale Bus Depot
Address: New York City, United States
Building type: Transportation terminal
Project type: Existing building retrofit
Engineering services: Electrical, power; Fire, life safety; HVAC, mechanical; Lighting; Plumbing, piping
Project timeline: 11/1/2010 to 10/1/2014
MEP/FP budget: $68,509,500


Located on the site of a former trolley barn in the Harlem section of Manhattan, the Mother Clara Hale Bus Depot has been transformed into a new sustainable bus depot that is projected to earn U.S. Green Building Council LEED certification. The project plays an important role in the New York City Transit (NYCT) initiative to move to hybrid-electric and ultra-low-emissions buses. The challenge to the team was to replace the existing aging facility with that of a state-of-the-art depot that meets the city’s transportation needs while minimizing its impact on the surrounding neighborhood. The project is projected to be the first major bus depot to earn LEED certification in the country.

As part of the design-build team with Silverite Construction, STV served as the architect- and engineer-of-record, and provided BIM services for this innovative facility. LEED design elements include a green roof to reduce the building’s carbon footprint, and a rainwater-collection system that will allow stormwater to be used for depot operations such as bus washing. The building’s south facade acts as a passive heating device, which features finish material with small perforations that allow air to be pulled in and preheated in the space between the facade and masonry. The warmed air is then drawn in by HVAC units, reducing the need for natural gas. Energy costs are further reduced by the use of translucent wall panels that allow natural daylighting.

Key to this assignment was the involvement of the Harlem community throughout the development of this project. From planning through design and construction, the process involved the Mother Clara Hale Depot Community Task Force, comprised of local community representatives and elected officials, Manhattan Community Board 10, West Harlem Environmental Action Inc. (WE ACT for Environmental Justice), and the Harlem Community Development Corp. Together, NYCT and the task force created a joint vision for the rebuilding of the Mother Clara Hale Bus Depot.

NYCT conducted its first-ever community design charrette early in the project development. Held across the street from the depot, it was attended by 150 community members, and the end result was that the bus depot was to be designed with the goal of LEED Gold certification—the first of its kind for the NYCT.

The use of BIM was instrumental in the LEED-certification process to facilitate an integrated design and reduce production time. As a visualization tool, BIM helped the design and construction teams detect conflicts and corrected errors that could have delayed construction. As a validation tool, BIM allowed STV to analyze many design options with regard to constructability, energy use, and other variables.


An innovative model of green-transit infrastructure and projected to be the first such facility to earn LEED Gold certification, the new Mother Clara Hale bus depot meets growing transportation needs with minimal impact on the surrounding Harlem neighborhood. With the community’s involvement from the start, the design-build team delivered a modern, sustainable depot to serve Manhattan residents for years to come.

Low-emission boilers, heat-recovery air-handling units, natural lighting, and solar air heating are among the 390,000-sq-ft facility’s features. Among other LEED design elements, the green roof uses plants to reduce heat gains in the building during the summer and absorb CO2 while also reducing stormwater runoff. Half of the open roof area is green, and the remaining 50% features a white roof. This high-efficiency element prevents heat gain in warm weather, yet does not reflect light or glare onto the neighborhood. The collection system sends rainwater to a 50,000-gal tank where, once the water is treated, it is reused in depot operations. This is estimated to decrease the depot’s water usage by as much as 1 million gal/yr, and reduce the stormwater surcharge on the city’s sewage system. The depot accommodates bus and employee parking, reducing local street congestion.

The dark-green, perforated wall finish of the building’s south facade allows air to be pulled in and preheated in the space between the facade and masonry, then drawn in by the HVAC units, reducing the need for natural gas. HVAC systems use custom roof-mounted, gas-fired heating and ventilating units with air-to-air heat-recovery heat exchangers and variable-frequency drive fan motors that handle 660,000 cfm of 100% outdoor air ventilation. The design includes NOx, CO, and H2 gas-detection systems and roof-mounted variable air volume, direct expansion, air-cooled gas-fired heating, ventilating, and air conditioning units. It also includes a fully condensing hot-water boiler plant; specialized exhaust systems to vent vehicle tailpipe emissions to the outdoors; a digital electronic building-management control system; and a 1,500-kW diesel emergency generator and 5,000-gal diesel-oil storage, transfer pumping, and piping system.

Translucent wall panels and glazing allow natural daylighting and reduce energy costs. Four 1,000-kVA, 13.8-kV, 480/277 V transformers provide second contingency service. In the event of power loss, two automatic transfer switches with bypass isolation will transfer emergency and priority 2 loads to a permanently installed emergency generator. One manual-transfer switch will transfer priority 3 loads to a portable generator.

Plumbing design includes three independent water services that are connected to the site water mains. Two supply the sprinkler/standpipe system; the other, the domestic cold water system. STV designed fire-suppression and HVAC systems in accordance with the owner’s requirements, using computerized fluid dynamics modeling.

Using BIM software, STV viewed each discipline’s 3-D model or selected building system, or a combined master model that included attribute information for generating schedules, reports, materials, and quantities. Additionally, the contractor used 4-D scheduling models to link 3-D CAD model components with activities from the design, procurement, and construction schedules.