ASHRAE Journal - December 2011 - 60

of the unit to allow them to be placed directly above the building shafts they serve. This approach resulted in a clean roof, which was a project goal because of the windows in the patient tower facing the low roof of the diagnostic and treatment building. Heat Recovery System Design. Each air-handling unit was provided with a dedicated heat recovery system installed within the enclosure of each unit to avoid heat recovery piping on the roof or outside the air-handling units. The heat recovery system is connected to the chilled water system to avoid an expansion tank at each unit and is ﬂushed through weekly by the CHW system during the warmest time of the day to eliminate the need for additional water treatment. Fire Alarm Shutdown Strategy. A critical component of hospital design is the air moving equipment ﬁre alarm shutdown strategy, as patients are difﬁcult to move. The design was developed with considerations to air-handling unit fan ﬁre alarm shutdown and the strategy was developed with the ﬁre alarm designers and electrical engineers. An important and innovative component of this system design was the addition of 12 smoke detectors in strategic locations to selectively control corresponding ﬁre smoke dampers and fan equipment while the rest of the hospital can remain in normal operation. Note that the building otherwise was exempt from duct smoke detectors (other than the AHU supply air duct detectors) as full area smoke detection coverage was provided for the hospital. Air Balancing. The size of the project (with more than 6,000 supply diffusers) meant that an air balancing report was needed to assist with keeping airﬂow within the acceptable range. The format developed in Excel included the necessary calculations for code compliant air changes, pressurization, and acceptable deviations from plans, which provided a quick turnaround time getting the necessary approvals from the state inspector. The third-party air balancing contractor prepared the air balancing report using this spreadsheet to automatically calculate deviations and color code grilles outside of acceptable tolerances.

California Codes for Hospitals
Probably the most signiﬁcant code requirement in California resulting in high energy use is the requirement for constant volume air systems for the entire building. The system cools the total airﬂow, meeting the code required air changes, and reheats the air in most zones to meet comfort conditions. The only exception currently is to provide supply and return side VAVs, which is cost prohibitive on most projects and has a poor payback, as maintaining the code minimum air changes does not allow enough turndown to realize signiﬁcant savings. This requirement combined with the required minimum two air changes per hour of outside air for all areas within the building results in extremely high energy use for cooling, heating, and fan energy. Recent code changes, such as updating the codes to only include pressurization requirements for rooms where infection control is a concern is a step in the right direction, but further steps are needed, such as reducing outside air requirements and allowing variable air volume (VAV) systems in non-patient areas to realize signiﬁcant energy savings. Departments within the hospital buildings can be maintained at the right pressurization relatively easily and cost effectively in relationship to each other, even with VAV systems in the less sensitive departments. Another signiﬁcant code change expected in the near future is changing the operating room humidity requirements from 30% to 60% RH to 20% to 60% RH, which will signiﬁcantly reduce the energy-intensive humidiﬁcation requirements. In coastal climates, the steam humidiﬁcation systems are potentially completely eliminated. Changes such as these will not only improve the energy use in California hospitals, but can also signiﬁcantly reduce the construction cost, which is also well above national average. Note that the 60% maximum relative humidity requirement will remain a major source of energy consumption with the demand for overcooling rooms with humidity controls, especially in operating rooms (where the desired temperature is often below the code minimum 68°F [20°C]).

Maintenance and Operation
The facility operators are stationed in the central plant. With the control system provided and visual mapping of all the system operations, the entire hospital and central plant can be monitored from this location, and alarms, warnings readily addressed. The facility operators were actively involved during the design and commissioning of the systems, which allowed a high level of familiarity with the installed systems and controls by the time of the project turnover. As part of the design-build delivery, a one-year warranty period was provided, during which time the design builder and control system provider assisted the facilities engineers with any potential problems with operations. This warranty period ended with a relatively small number of issues and warranty calls for a facility of this size.
60 ASHRAE Journal

Cost Effectiveness
Cost effectiveness was one of the key drivers for this project. Cost was monitored from the beginning of the design. All major design decisions and owner requests were reviewed and approved with actual cost information. The project was virtually free of contractor generated change orders. Almost all change orders were owner requested changes during the design and construction of the project. The project was completed ﬁve months ahead of schedule presenting signiﬁcant value to the owner, as well as the design and construction team.
ashrae.org December 2011

ASHRAE Journal - December 2011

Table of Contents for the Digital Edition of ASHRAE Journal - December 2011