Children’s hospital designed by kids, powered by Cummins
During the early stages of the design of the hospital, which opened in September 2006, architects asked young patients what they thought a hospital for kids should look like. The colorful exterior represents the goal of the new hospital: responding to children’s needs.
From the state-of-the-art medical facilities that aid patients’ recoveries to the standby power system that ensures their safety, the hospital’s vision is to reduce stress and promote healing in ways that are uniquely tailored to the children it serves. With a focus on family-centered care, the hospital includes sleeping facilities for parents in each patient room, a pet visitation room and healing gardens. However, most patients are treated on an outpatient basis and visit the hospital’s diagnosis, assessment and treatment clinics. This clinic-based program has been used as a worldwide model for outpatient care.
Alberta Children’s Hospital is part of the publicly funded Calgary Health Region health care system, which serves more than 1.2 million people in Calgary and surrounding communities.
Building a hospital specifically for children drove and impacted every part of the design. That’s a big reason why hospital officials chose Cummins Power Generation Inc. generators and controls for the 3.5-megawatt electrical needs of the 133-bed, 750,000-square-foot hospital.
“Everyone on the design and construction team agreed that intangible factors—not just price—were important, because it is a children’s hospital,” said Gerry Stebnicki, electrical design team leader with Stebnicki + Partners in Calgary. “This made the whole approach unique. We sent a request for proposal to generator manufacturers stating our essential performance requirements rather than a complete design; all major components of the hospital were chosen that way. We chose Cummins Power Generation within that context, because they offered the best value of all the tendered proposals. Once they were chosen, they participated in the budget control and design decisions, working in concert with the rest of the group to make it happen. That’s a big reason why the project was so successful.”
Redundancy for reliability
One example of the planning team’s quality-driven focus is the high reliability designed into the standby power system. The team created N+1 redundancy at all levels.
“Although we initially recommended two 2-megawatt generators to serve the hospital’s 3.5-megawatt total load, hospital officials wanted to be able to run at full load even if one generator was down—so there are three generators,” Stebnicki said.
The three generators—Cummins Power Generation model DQKC—are housed in a building 1,312 feet away from the main building. This minimizes noise and vibration in the hospital, allows ground-level access to the generators in an emergency and simplified the design of the generator cooling system.
Because of the distance between the power building and the hospital, Stebnicki chose 4,160-volt supply lines to the hospital rather than the Canadian standard of 600 volts.
“Increasing the voltage allowed us to deliver the same amount of power with smaller conductors,” he said. “We saved so much on the conductor costs that the overall standby system ultimately cost less.”
The 4,160-volt lines run underground and then through a series of duct banks to the main building’s penthouse. From there, power is stepped down to 347/600 volts.
The design team chose the PowerCommand digital master control (DMC) system from Cummins Power Generation for two reasons: complete integration with the generators, and its ability to meet interoperability requirements.
There are two touch-screen control panels for the generators and transfer system—one in the generator building and another in the penthouse. They are linked by fiber optics.
“The system can be controlled from either point—and changing anything on either screen updates the other screen in real-time,” said Steve Falk of Trotter & Morton, the project’s electrical construction manager. “It is also possible to control the system through a PC from anywhere, but the design team chose not to implement that capability—partly for security reasons and partly because qualified personnel are in the hospital at all times.”
According to hospital Maintenance and Engineering Manager Dave Drinkwater, Calgary’s municipal power company, Enmax, is a highly reliable source of power. Outages are rare. In fact, there have been none since the hospital opened.
”In the rare event that Enmax needed to shed loads, we would be considered a high priority,” Drinkwater said.
System exceeds standards
The Canadian Standards Association’s Z-32-04 standard, “Electrical Safety and Essential Electrical Systems in Health Care Facilities,” requires that generators be online within 12 seconds of utility outage. According to Stebnicki, the PowerCommand system does much better than that.
“The DMC has extensive capabilities,” Stebnicki said. “It enables operators to monitor all major loads in the building and provides history on the profiles of all those loads, which is a very effective planning tool. When the system detects a loss of normal voltage, the UPS takes over and can, theoretically, supply power for all critical needs for hours. But the UPS doesn’t have to supply power for that long. That isn’t necessary, because as soon as there’s a power outage, the system also sends a start signal to the generators.”
Once the generators are up to speed, which takes about 10 seconds, the system again transfers power smoothly to the generators. Then the system senses when the utility comes back online, and again makes a smooth, synchronous switch back to the utility power. Fuel capacity for the generators is 13,208 gallons (50,000 liters); depending on loading and the season, the generators could power the entire hospital for approximately 44 hours.
In a simpler system with one standby generator, the move from one power source to another would be accomplished through a transfer switch. “But since the hospital is much more complex—three generators, UPS and feeds from two utility substations—there actually are no transfer switches,” Stebnicki said. “Switching is done through the main breakers; the DMC software accomplishes seamless, synchronous switching.”
The new hospital also exceeds other requirements of Z-32-04. For example, the standard lists critical loads that must be connected to the emergency power system. For an acute-care facility such as Alberta Children’s Hospital, that list includes operating rooms, the intensive care unit, trauma care and emergency facilities, stairway lights and power outlets around every patient. The list also includes ventilation fans—in both the operating rooms and patient rooms—that determine airflow direction and therefore help to control the spread of infection.
However, since just two of the three 2-megawatt standby generators are needed to handle the hospital’s entire load, it is unlikely that the hierarchical system will be called upon. Drinkwater’s staff tests the generators and associated equipment weekly using actual hospital loads rather than a load bank.
Another design element in Alberta Children’s Hospital that contributes to overall reliability is its interstitial floors: Every other floor is solely devoted to mechanical, electrical, telephone and plumbing equipment. Sealed, permanent conduits pass through each interstitial floor into the health care areas below. This contrasts greatly with the previous paradigm in which equipment was jammed into the space above a suspended ceiling.
In Alberta Children’s Hospital, the interstitial floors are the same height as the health care floors—14 feet—which provides more space to work in (and a floor to work on), making maintenance faster and more efficient. More importantly, interstitial floors allow workers to “operate” on the building’s systems without interrupting or contaminating the vital health care activities occurring below.
Everyone on the Alberta Children’s Hospital design team—including Cummins Power Generation—has responded to problems with innovative solutions. But, then again, innovative solutions were the requirement, since the health—and often the lives—of children hang in the balance every day.
Minneapolis-based Cummins Power Generation, a subsidiary of Cummins Inc., provided this case history.