Harley Ellis Devereaux: Crittenton Hospital Medical Center, Cornerstone Bed Tower Project

New construction of a hospital/health care facility.

By Harley Ellis Devereaux August 14, 2014

Engineering firm: Harley Ellis Devereaux
2014 MEP Giants rank: 72
Project: Crittenton Hospital Medical Center, Cornerstone Bed Tower Project
Address: Rochester Hills, Mich., U.S.
Building type: Hospital/health care facility
Project type: New construction
Engineering services: Automation/controls, electrical/power, fire/life safety, HVAC/mechanical, lighting, energy/sustainability, plumbing/piping, and other
Project timeline: 9/8/2011 to 5/1/2014
MEP/FP budget: $1 million


One of the firm’s challenges was to minimize the size of the mechanical room without compromising the accessibility and maintenance of the equipment. Space was saved by depressing the first floor, allowing for taller indoor air handling units. The air handling units were uniquely configured with the return fan stacked on top of the supply air tunnel, saving valuable floor space. The team had to deal with a challenge of matching floor-to-floor heights of the existing facility. In looking at several ductwork routing layout possibilities, the design team collaborated to provide two large central duct shafts that lessened the size and length of duct routes. This made it possible to provide many areas with ceiling heights greater than the default 8-ft high where the floor-to-floor height was only 12 ft 5 in. The existing site primary utility service did not have available capacity to accommodate the building addition and associated increased load. Additional considerations were also necessary to accommodate the limited project budget, aggressive schedule, and restrictive space for new systems.


Multiple smaller boilers were selected to allow for the most efficient operation of the system, that is, low firing rates, and cooler return water temperature. A shell and tube heat exchanger was provided and connected to the hospital’s steam system to serve as a backup to the hot water boilers. The fan coils for the 55-ton variable refrigerant flow system were zoned to extract heat from heat dissipating areas like communication closets and electrical rooms and routed to walkways providing heating without the need to run the compressors. Another space-saving tool used was a pre-engineered waste and vent system. This system worked well with the stacked toilet rooms in the bed tower, eliminating the vent stack that typically follows the waste stack. The end result was a reduction in cost and saving of space without compromising the performance of the waste system. To address these issues, the existing hospital’s utility service was replaced with a new dual 13.2 KV primary service, with new 15 KV switchgear and automatic throw-over scheme contained within a stand-alone prefabricated switchgear house, which was released as an early pre-purchase package. To provide seamless transition without interruption of the site, critical phasing was specified to allow changeover of existing loads to the new system prior demolition of the existing service.