Power Protection Systems: Protecting Investments in Capital Health Care Equipment
As medical facilities evolve into highly automated digital hospitals dependent on sensitive electronic equipment for all aspects of patient care and administration unseen power anomalies can become serious problems. With advancing technologies and increasing federal regulations, hospitals are shifting toward almost entirely electronic IT systems, imaging equipment, and clinical medical equipment. Protecting these growing capital investments is a pressing concern for hospital administrators and health care practitioners alike. With patient well-being and business efficiency to ensure, power to critical IT data, diagnostic systems, and clinical medical equipment is paramount. However, many health care providers are not aware of power interruptions until they occur.
Clean, uninterrupted power is critical for medical equipment and health care IT systems. If power fluctuates for just a few moments, data can become corrupted or lost. Internal system communications can lock up and require a reboot, damaging sensitive components and interrupting crucial procedures. As medical technologies and procedures become ever more sophisticated, the potential problems and risks to equipment intensify. For example, clinical lab instrumentation has evolved from simple, low-speed, single-purpose devices to complex, high-speed, integrated devices that support multiple types of analysis. Internal components may include laser light sources, mechanical turntables, heating/cooling elements, pipetting devices, and numerous electronic sensors and computing circuit boards. These high-end instruments use components so miniaturized and sensitive that they can easily falter and fail under power conditions that earlier generation equipment may have withstood.
Also, information technology is transforming hospitals. While in the past, IT systems supported primarily administrative functions, they are now found in nearly all clinical and diagnostic functions. Patient medical records are being stored electronically. Diagnostic imaging scans are now stored digitally in picture archiving and communication systems, requiring tremendous storage capacity. Every clinical department uses IT systems to collect, store, and share patient information. The availability of these systems on a round-the-clock basis is critical for the hospital to deliver the best patient care.
Despite the continuously growing power requirements for hospitals and outpatient health care facilities, utility power companies are not mandated to provide digital grade power. The American National Standards Institute, which coordinates and administers the U.S. standards and conformity assessment system, defines the acceptable voltage variation on the utility to be typically in the range of plus 5.7 percent to minus 8.3 percent from absolute specification. For example, utility service with 208-phase voltage can actually range from 191 to 220 volts. That range often exceeds manufacturer specifications for sensitive equipment like diagnostic imaging systems and lab instrumentation.
It is important to understand that power disturbances and problems do not result solely from power outages. Power frequency variations, line noise, harmonics, over- and under-voltage, power spikes, and sags are also common causes of power quality problems and ultimately lead to disruption of business and service continuity. These issues often arise due to other medical instrumentation tied into a common power source. Combined, these power quality problems cost an estimated $119 billion to $188 billion in lost service, productivity, and equipment failure to the U.S. economy annually, according to a 2001 Electric Power Research Institute study on the cost of power disturbances to industrial and digital economy companies.
In addition to the utility power issues, health care facilities have other unique power requirements and regulations. The National Fire Protection Association 99 and 110 standards require emergency generators to obtain the minimum level of reliability and performance. The Joint Commission on Accreditation of Healthcare Organizations requires facilities to demonstrate the reliability of emergency power systems through generator testing at least 12 times annually. Health care facilities must adhere to these standards to continue to receive accreditation and to comply with federal power regulations.
For all mission-critical systems in a hospital, the outcome of power disturbances is the same. In-process diagnostic scans are aborted and must be rescheduled. During delicate procedures in operating rooms using interventional radiology, the monitor fades to black, the physician loses sight of the catheter, and, in some cases, must wait for power to return just to exit the body safely. In clinical lab settings, in-process testing is interrupted, reagents are wasted, time-sensitive assays are ruined, and blood samples must be redrawn. Electronic patient records may be corrupted or lost and departmental communications are unavailable, compromising HIPAA issues and concerns.
When power disturbances occur, patients are inconvenienced and physicians, technicians, and hospital administrators become frustrated with especially high-volume workloads, long backlogs, and overbooked schedules. Valuable medical equipment sustains insidious damage and the hospital loses a measure of image and goodwill, and potentially tens of thousands of dollars in revenue.
Proactive planning can prevent the devastating consequences of power disturbances. Most medical facilities have backup generators that provide emergency power within 10 seconds of an outage and Transient Voltage Surge Suppressors that absorb potentially harmful power surges. Generators and surge suppressors are falling short and are mere band-aid measures for systemic problems. Even with backup generators, systems are still at risk for power interruptions during transfer time (the span between power interruption and the start of generators). This transfer time may only be a few short seconds, but that is enough time for equipment to crash and, as a result, jeopardize patient outcomes, add to repair costs, reduce staff productivity, and lose revenue.
Uninterruptible Power System
An uninterruptible power system (UPS) helps avoid power irregularities by providing clean, uninterrupted power to medical equipment and data. A UPS helps health care professionals guarantee the integrity of care by ensuring that connected medical equipment operates at optimum levels at all times.
A UPS resolves utility power problems and supplies continuous power to all downstream equipment, whether the power source is a battery, generator, or utility. With an online UPS, equipment perceives no switch-over time between power sources.
A UPS for medical facilities typically ranges from 300 volt amperes to more than 1,000 kilovolt amperes. A small UPS protects a systems central computer during a power disturbance, and provides enough backup power to save data and preclude a hard shutdown. A larger UPS provides a continuous flow of conditioned power to the entire system and enables normal equipment functionality even during a total loss of power.
There are three categories of UPS available today: standby, line-interactive, and online.
With a standby UPS, the protected equipment runs off normal utility power until the UPS detects a problem. At that point, the UPS quickly activates an inverter that converts DC battery power into the AC power needed by the equipment, and runs the equipment from its own battery. The battery provides enough time (typically 5 to 15 minutes) to complete a process and shut down the system in an orderly way.
A standby UPS is a low-price solution for noncritical applications that only need minimal power protection. Because raw utility power is being used during normal operation, a standby UPS doesnt regulate voltage and frequency variations until they become severe enough to trigger the switchover to battery power. Therefore, a standby UPS is more appropriate for individual PCs, and more expensive, but not appropriate for noncritical instrumentation, where protection is needed for vital systems.
A line-interactive UPS regulates voltage by boosting input utility voltage or decreasing it as necessary before allowing it to pass to the protected equipment. A line-interactive UPS offers more protection than a standby UPS. It is generally used with network devices such as hubs and routers, small communications systems, servers, laboratory equipment, and small workstation environments.
A line-interactive UPS simply keeps power within an acceptable voltage range. Most applications are involved with laboratory instrumentation and diagnostic equipment such as ultrasound and monitoring equipment. However, digital imaging and clinical laboratory systems need power with a pure sine wave, which a line-interactive UPS does not accommodate.
An online UPS continuously uses an inverter to protect against all nine types of power contamination and create clean, perfect sine wave power for downstream systems. Critical medical equipment and hospital IT systems are completely isolated from raw utility power and all its irregularities, using a double conversion process. With double conversion online technology, incoming utility AC power is conditioned and converted to DC power, a small portion of which is used to charge the UPS battery. The remaining DC power travels to the inverter, which produces new, perfect sine wave AC power to deliver to the instruments. Only this type of perfect sine wave power enables sensitive equipment to perform to manufacturer specifications.
An online UPS design offers the highest level of power protection available, and therefore is the only real choice for mission-critical equipment that is highly sensitive to power fluctuations, and for which downtime carries a high price tag. Some 95 percent of UPS used in mission-critical applications are online systems a figure that has risen more than 15 percentage points since 1998 and is not expected to abate.
Identify and Resolve the Risks
Are power specifications required by your mission-critical IT and medical equipment being met? Is the power infrastructure sufficient for new equipment to be installed? Are grounding issues causing hidden problems? A power quality assessment should be conducted periodically by a qualified electrical engineer, electrical contractor, or health care facilities manager with electrical engineering expertise.
- Assess all areas of the power infrastructure, including wiring, loading, line balance, polarity grounding, harmonics;
- Identify insidious power problems that can corrupt data and hardware;
- Determine if existing power infrastructure capacity is being approached or can accommodate planned growth; and
- Define and provide solutions to protect patient-critical or highly expensive electronic capital equipment.
Because of the unique power requirements for medical devices and instrumentation, certain UL listing requirements for patient vicinity, and cost of expensive equipment repair, not all UPS devices may be appropriate. First, a medical-grade surge protector may be adequate for a simple application such as a pharmacy admixture system. Line conditioners may also be an alternative for office diagnostic equipment such as scopes and EEG equipment. UPS are generally utilized for expensive capital equipment and/or diagnostic and interventional instrumentation where data integrity is vital to patient outcomes and continuous operation is required for cost avoidance. It takes expertise to size the UPS correctly for the equipment being protected, especially since clinical lab equipment and diagnostic imaging equipment have such immense and variable appetites for power. This is due to high current in-rush demands upon calibration of laboratory equipment or the enormous power in-rushes involved in diagnostic imaging applications.
In addition to the types described earlier standby, lineinteractive, and online UPS can be configured to provide different levels of support for one or more connected devices:
Partial System Protection prevents the computer element of the system from locking up, requiring a hard shutdown, or losing data during a power disturbance. The UPS provides enough backup power to save data and support an automated shutdown of the computer system. Typically, single-phase UPS solutions can meet this requirement, which offers data protection but not full protection for significant equipment investments.
Centralized Protection is achieved with a shared UPS connected to multiple protected devices and sized to provide sufficient coverage for all of them. In the case of a hospital computer room or data center, the UPS provides enough backup power to save data and support an automated shutdown of the computer system. For systems that cannot be shut down, the UPS provides enough runtime before the backup generator can be started in the event of extended power outages. Through economies of scale and streamlined power management, this configuration can save time, money, and space.
Distributed, Full-System Protection, with a UPS dedicated to each instrument, enables medical equipment to function normally even during severe power disturbances and to properly conclude procedures during total outages. This approach virtually eliminates power issues as a factor in equipment degradation or downtime.
It is a common assumption that all incoming power from an electrical outlet is equal. When investing in capital equipment, medical devices, and diagnostic instrumentation, it is wise to protect that investment and preserve quality of patient care by reviewing the specific power needs, requirements, and cost of equipment downtime related to power issues. Applying the appropriate power protection solution through the use of surge protectors, line conditioners, transformers, and UPS should be included as a standard part of health care equipment procurement policies and procedures. This can be accomplished through a solid understanding of the applied health care technologies and the hospitals electrical infrastructure between biomedical engineering, facilities management, electrical engineering resources, and knowledgeable power protection vendors who are capable of specifying appropriate solutions.
