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Anne E. Robinson

Leach Wallace Associates Inc Consulting Engineers: New Patient Tower Silver Spring, Holy Cross Hospital

Mechanical and Electrical Engineering


Leach Wallace was commissioned to design the expansion of the 300,000 sf New Patient Tower at Holy Cross, located in Silver Spring, Maryland. The expansion of the hospital included a 150 bed patient tower, including a new central energy plant and major renovation to the existing front lobby for circulation to the new tower. The major site renovations included a large expansion to the existing parking garage, new site utilities, underground fuel oil storage tanks, generators on grade, and site lighting.


A new central energy plant was provided to the penthouse of the new bed tower to service the entire campus. The new central energy plant included included a 3,000+ ton chiller plant with variable flow primary pumping systems and rooftop cooking tower yard, 50,000 lb/hr high pressure steam plant with new feed water systems. It also included central air handling systems with energy recovery, general and critical exhaust systems, domestic hot water plant, as well as main electrical distribution rooms, stair pressurization systems, central elevator machine room and smoke purge.


At the basement and ground level floor new central campus normal power distribution, emergency power distribution and paralleling gear room, central fire pump, domestic water booster pump, and steam-to-hot water heating plant. For energy recovery, a 750 ton heat pump chiller was provided, which will pre-cool the campus return chilled water returning to the central plant in the penthouse, and rejects its heat through condenser water to a loop in the heating hot water plant. All major air distribution was delivered to the floors as medium pressure, with air terminal units in the spaces to maintain individual zone loads.


The project was designed to achieve a “certified rating” from the USGBC. In addition, Green Guides for Healthcare (GGHC) Facilities document was utilized to identify a list of proposed sustainable features. This facility is seeking LEED Silver.