Building a Resilient and Reliable Power System for Health Care Occupancies
By Danna Jensen, Principal - Certus Consulting Engineers
Many unique challenges are associated with designing electrical systems for hospitals and other healthcare facilities including complex emergency power demands and increased resiliency and reliability requirements. Here at Certus, we understand that many healthcare facilities desire to maintain operations during sustained utility power outages. This includes operating the large power users on emergency power such as cooling, cooking, and sterilization equipment, 100 percent of medical imaging modalities, and other loads that are typically above and beyond what the codes and standards require. These all have a substantial impact on the emergency power supply system (EPSS) design and sizing.
Our experience has proven that we are not only incredibly skilled at knowing the complex web of applicable codes, but also real-world expectations on system operation. We know that an oversized generator will cause maintenance problems such as wet stacking, but under sizing the system could cause unnecessary downtime or damage to equipment.
Our goal is to “right-size” the EPSS and work closely with the facility stakeholders to understand their needs and deliver a project that meets them.
Whether it be in designing a brand new system, or upgrading an existing one, we use strategies such as:
Adding multiple step loading on the system
Using rectifiers to reduce harmonics
Variable frequency drives to minimize starting impact of large motors
We also may look at adding power conditioners or uninterruptible power supplies upstream of sensitive electronic equipment such as medical imaging to reduce voltage and frequency dip requirements. We also work very diligently to collect real operating data from similar facilities to build a database for ourselves as the industry continues to change.
However, “right-sizing” is only part of the equation. There have been many significant events over the past several years, both man-made and natural disasters that continue to drive focus on disaster planning and preparedness in many industries, and healthcare is no exception.
The resiliency and reliability of the emergency power infrastructure requires concerted attention and at Certus, we take this very seriously. We understand that the system must be designed to withstand natural disasters such as earthquakes, floods, tornados, as well as human attacks.
Consideration of the equipment location is key for resiliency planning. For instance, if the hospital is an area subject to hurricanes or flooding, we may look to locate the EPSS on an upper level to provide flood-proofing, or indoors to protect against high winds. We need to ensure that the equipment is accessible only to qualified personnel whether it is located indoors or outdoors. If the equipment is located outdoors, consideration is given not only to lateral protection, but also protection from above from malicious attempts of damaging equipment through the open air of a generator yard.
Another consideration for resiliency planning is louvers locations. Louvered ventilation is necessary for proper operation of equipment; however, the louvers present a vulnerable opening to the vital equipment and we carefully plan equipment locate with adequate distance from any exposure.
In addition to resilient systems considerations, the EPSS must be reliable and designed to ensure proper system operation under any number of events such as short circuits, load surges, elevator operation, or imaging equipment. Adding redundancy in quantity increases the reliability of the system by eliminating a single point of failure. Certus analyzes the options for reliability and redundancy to determine the right size and quantity of equipment to provide the ultimate reliability.
The health care industry continues to change and Certus is committed to staying on top of the industry trends and informing clients of the best possible scenarios to work within their budget and requirements. We are truly dedicated to designing the best EPSS possible that exceeds expectations for years to come.