Mercy Medical Center Mechanical Engineering
Oshkosh, WisconsinThe mechanical systems for this facility were designed with flexibility and expansion capabilities in mind. The major mechanical equipment is located in two principal areas of the building for ease of service and maintenance. Piping and ducts are arranged to permit future additions and modifications to the systems in response to the changing needs of health care.
Heating
The heat for the building is provided by three fire-tube steam boilers, sized so any two can carry the load for the building. This design permits better turndown for summer operation versus using two 100% boilers. There is space reserved for a future boiler of similar capacity.
Chilled Water
There are two centrifugal water cooled chillers. The chillers are each sized for 50% of the total load and both are required to run on a design day. Space is reserved for a future chiller. A two cell cross-flow, forced draft tower with indoor sump is used for condenser water cooling. Variable speed drives on the tower fans provide capacity control.
The chilled water pumping system is a primary-secondary system with two secondary pumps operating on variable frequency drives with signals from pressure differential switches in the air handler rooms.
Air Handling
There are three air handling units in the hospital and one in the Physician Office Building. Each air handler is a field-built double wall unit with 100,000 CFM capacity. Each unit is designed to run with only one supply or return fan operating in the event of a failure. All units are capable of 100% outdoor air economizer operation. All units use air flow measuring to ensure minimum outside air quantities are met and to perform supply and return flow tracking.
Mechanical System Features
The operating rooms have two position boxes for occupied and unoccupied modes. There are also VAV boxes on the return side to ensure that the O's are always positively pressurized.
A number of exhaust fans are provided for specific purposes. The systems are divided into hazardous exhaust and general exhaust. Exhaust fans consist of in-line fans in the penthouse and rooftop exhaust fans.
Medical Gases
Medical vacuum, medical air and waste anesthesia evacuation equipment are all located in a room in the penthouse. Nitrous oxide, nitrogen and carbon dioxide are all provided from a manifold room located near the loading dock. Oxygen is provided from a liquid oxygen tank located near the loading dock area with an emergency connection located near the overhead door into the chiller room.
All gases are alarmed locally as required with alarm panels typically located at nurse stations. Master alarm panels are located in the maintenance shop area and the security office.
Plumbing
Domestic water pressure is boosted by a triplex pump system. Hot water is provided by two 100% capacity, steam semi-instantaneous water heaters. The water is generated at 140 degrees F and mixed down to 118 degrees F for general use with 140 degrees F provided to the kitchen.
Water is softened for use in certain HVAC system
makeup and for hot water. A brine pit is located outside the building and bulk salt is delivered to the pit.
Controls
A Siemans DDC system is provided throughout the facility. Additional alarm points are monitored for critical systems such as the fuel oil leak detection. A number of critical coolers in the kitchen and lab areas are monitored as well.
Miscellaneous Systems
There is a dedicated chiller with a split condenser serving the MRI. The chiller includes city water back up in case of loss of power or other failure of the chiller.
There are two modular cooling units providing supplemental cooling for the IS equipment room on ground floor.
A glycol slab heating system is provided at the two main entrances for snow melting purposes. High-density polyethylene tubing is imbedded in the slab for this system.