Taking a Holistic Approach to the Imaging Suite
Whether in a new-build or retrofit facility, best practice implementation for a healthcare imaging suite involves more than incorporating the latest designs in aesthetics and patient comfort. To ensure maximum utilization and optimal performance of the radiology unit, best practices in power and cooling infrastructure must also be applied to the total implementation.
By improving the infrastructure that supports the imaging suites, architects and engineers can eliminate equipment downtime, increase image quality and improve the overall patient experience.
Risks of downtime
Hospitals and code-enforcement agencies go to great lengths to ensure patients are minimally impacted during utility outages by deploying back-up generators for the facility. However, computer equipment, even backed up by a generator, will be rendered temporarily unusable during a utility power loss, brownout, or voltage sag, as generators have approximately a 10-second delay between the outage and the time they can fully assume the load. This 10-second outage will cause IT equipment to reboot and negatively impact users. Imaging suites are no exception.
For instance, imagine a voltage sag that impacts imaging operations during a busy time of day. The imaging device will experience a break in power continuity-10 seconds for the generators to come online, plus the time it takes the IT equipment to reboot-rendering useless (or potentially losing) any images that were being captured at the time of the outage.
To compound matters, after an outage, medical personnel may be required to run a “phantom” scan which calibrates the equipment and ensures that the imaging device is working properly. The full startup process after a loss in power can take up to 45 minutes. Imaging labs are one of the busiest places in a hospital with tight and inflexible schedules. Having a single suite (or even worse, all of the suites) out of order for 45 minutes would make any radiologist shudder at the thought.
Power outages can cause lost income due to cancelled patient appointments and frustrated staff with lower productivity. Voltage sags and surges will produce substandard image quality and may even damage the radiology equipment itself.
Backup power solutions
Implementing an uninterruptible power supply (UPS) system is the only way to bridge the power continuity gap between an outage and the time it takes a backup generator to kick on or have utility return.
There are three approaches to UPS deployment specific to the imaging suite: protecting just the computer control room, protecting each individual imaging device with a dedicated UPS, or protecting the entire radiology laboratory from the same UPS. In these three scenarios the size and operating parameters of the UPS needed will greatly increase.
Best practices for UPS deployment would not include the first option of protecting computers only, although that strategy is commonly used by facility managers and imaging device manufacturers due to lower purchase cost and ease of installation. Protecting only computer controllers will prevent images from being lost, but it leaves the entire imaging device vulnerable to lengthy downtime. In many cases, protecting only the computer controllers may be unintended and the facility manager or operator incorrectly believes his UPS protects all aspects of imaging. This can occur when, for ease of purchase, a small UPS (under 25 kVA) is bundled with the imaging equipment during purchase. The end user may not be aware that the most critical component of the imaging lab, the imaging equipment itself, is vulnerable to unreliable utility power.
Best practices in power protection involve deploying a UPS to protect both the imaging equipment and computer peripherals which utilize electricity. More and more labs are deploying large UPS systems to cover multiple imaging devices in a centralized UPS approach as opposed to a dedicated, standalone UPS for each imaging device. This centralized UPS strategy is less costly compared to purchasing multiple smaller UPS systems, and is also more energy-efficient which will save costs in operations.
Not all UPS systems are created alike. The UPS that resides in the data center and performs spectacularly might not be able to successfully protect the hospital's imaging lab. Imaging equipment has unique and extreme power demands, far greater than ordinary IT equipment which utilizes a consistent level of electricity.
Imaging devices produce a high in-rush of current. A typical cardiac catheterization unit might need only 12 amperes of power to operate, but it will have a momentary in-rush of more than 240 amperes during the scan itself. Think of this as going from 0 to 60 miles per hour in your car in less than one second (over and over again!). Your car's engine wasn't designed for such extreme performance, and the same goes for most data center UPS systems.
The typical UPS has a low tolerance to high in-rush conditions and will overload. This will cause the unit to run on the electrical bypass and not take advantage of power conditioning or the battery protection the UPS offers. This problem has led many manufacturers and engineers to oversize the UPS by two or three times to mitigate overload conditions.
It is important to know that the newest generation of UPS technology utilizes the latest in inverter and rectifier design so the need to oversize the UPS is no longer necessary. Today's best UPS systems can easily handle the in-rush and over-current produced by radiology devices without having to oversize. Think of this UPS as the eco-friendly dragster, which can take that 0 to 60 mph jump while also being energy-efficient. Utilizing this new technology can also save capital costs because you are only purchasing the size of UPS you truly only need.
One last innovation that should be included in power evaluations is flywheel or rotary type UPS. A flywheel is a spinning mass that, when the power fails, utilizes its inertia to produce electricity and is an alternative or supplement to batteries. Flywheel technology is especially ideal for hospital and imaging environments as the in-rush needed by the imaging devices is handled by the flywheel. And, thanks to the presence of the hospital's generators, the short ride-through until the generator's start is easily bridged.
Getting design, engineering, and IT on the same page
When planning an imaging suite, it's important to make sure architect, engineer, and IT staff are all involved in the process. Every bit of real estate is vital inside a hospital, making it even more crucial to plan ahead if a UPS system the size of several refrigerators is going to be implemented. The architects need to know early on what engineering and IT have in mind for power strategy so they can plan the room designs accordingly. For instance, if the facility will be installing a centralized UPS system for the entire lab, exam space can be freed up and suites can be enlarged. However, with the centralized approach, more equipment housed in the mechanical room will mean more heat and precision cooling will be needed to ensure the equipment is operating within parameters.
Planning for the imaging suite in a healthcare facility is no small task. Maintaining continuity should be a top priority as without constant availability images cannot be captured and patients cannot be served. Although each facility has its own unique needs, the protection of not only computer equipment, but also the imaging equipment, must be considered. Be aware, though, that your preferred UPS might not be able to handle the extreme power demands of this environment. Perhaps most importantly, all of the parties involved-including design, engineering, and IT-need to have an open line of communication from start to finish, ensuring that the job comes in on budget and space, efficiency, and availability are maximized. HD
What about cooling?
The imaging equipment and the UPS itself will generate heat. To ensure the equipment's operating life is maximized, cooling will be needed.
Ceiling- and floor-mount precision cooling is ideal for small areas and heat loads under 28 kW (8 ton) such as computer and equipment rooms.
To cool the exam suite itself and places where people and equipment share the same space, ducted air from a ceiling- or floor-mount unit in the equipment room can also be utilized.
For some devices like an MRI, a process chiller will be needed to help supply chilled water to cool the imaging devices' internal components. Emergency valves utilizing city water must also be planned into the design.
Is the cooling on emergency power? What's the point of having your lab equipment on emergency power when you're not able to cool it or provide chilled water? An emergency power plan needs to incorporate the cooling of devices running on generator power.
Critical questions for architects, engineers, and IT
What is the UPS strategy; centralized or decentralized?
How does the UPS impact the size of mechanical rooms?
Can my precision cooling units optimize floor space utilization?
How much cost can I save with a centralized UPS design?
Can the UPS handle the in-rush?
Is the UPS oversized or will the UPS exceed its maximum rating?
Is my UPS able to walk the hospital's generator in or is the UPS and imaging equipment going to be slammed with electricity during generator start up?
Does my hospital have a green initiative? Can I use flywheels instead of batteries?
If my imaging equipment is on emergency generator power, is my cooling equipment?
Besides the suites, what is my power and cooling strategy for network closets, PACS workstations, and other server/storage devices?
Dan Draper is Healthcare Industry Marketing Manager for the Liebert Products and Services business of Emerson Network Power. Healthcare Design 2010 March;10(3):36-41