NFPA Journal

What does peak electrical demand at a hospital actually look like? That question has vexed designers and engineers for years. Until recently, only theoretical calculations and small-scale studies had shed any light on the topic. Then the COVID-19 pandemic hit. 

For the first time in a century, researchers had the opportunity to examine electricity use at hospitals stressed to the max—ICU beds full, ventilators whirring, infusion pumps beeping. Supported by the Fire Protection Research Foundation, the research affiliate of NFPA, researchers from Mazzetti, a health care engineering, planning, and design firm, embarked on a yearlong project starting in the spring of 2020 to study electricity use—specifically, plug loads, or the energy used by equipment plugged into receptacles—at eight hospitals across the country, each chosen because they were expected to see surges in patients during the pandemic. 

Later this month, the foundation will publish a report on the study—Electric Circuit Data Collection: An Analysis of Health Care Facilities—which found there’s a large gap between the actual electrical demand hospitals experience during an unprecedented event like a pandemic and what most facilities’ systems are currently designed to accommodate—in fact, systems are often designed to handle anywhere from 100 to 700 percent more demand than what they actually see, according to the report’s authors. 

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Experts say the findings didn’t come as a shock. Even before the report was released, the National Electrical Code® (NEC®) had already been moving toward requiring smaller electrical systems for certain parts of health care facilities. But the new study, which experts say is the most comprehensive effort to date to examine the gap between electrical load calculations and actual peak demand at hospitals, raises legitimate questions over whether the NEC should undergo further revisions to keep up with the efficiency of modern health care equipment and electrical systems. 

“This study introduces some interesting data, and it’s not surprising to me that modern hospitals aren’t using as much electricity as they had in the past,” said Corey Hannahs, a senior electrical content specialist at NFPA. “For several years, we have been seeing many factors, such as LED lighting and motion sensors, combined with government initiatives to lower energy consumption, driving a drop in actual electrical loads at hospitals.” 

Efficiency trend 

When the concept for the foundation study first began to take shape in 2019, the plan wasn’t to look exclusively at electrical loads in hospitals. 

“We planned to look at electrical loads in multiple occupancies,” said Troy Savage, a project manager at Mazzetti, who served as the study’s lead author. “But after the pandemic started, we realized we had a unique opportunity—for the first time in a hundred years, you could say, [since the 1918 flu pandemic]—to look at electrical loads in hospitals during a pandemic. At the same time, offices were shutting down, schools were shutting down, so it simply didn’t make sense for us to look at those other occupancies.” 

Savage and other researchers received approval from the foundation to shift the focus of their study to hospitals and chose eight health care facilities across the country in which to install hundreds of meters. The meters measured electricity use in several areas of each hospital, from standard patient rooms to imaging departments to intensive care units. Generally, the study found that electrical systems were the least oversized for areas like the ICU, where powerful equipment like ventilators can be operating nonstop. In the highest plug load researchers observed during the study, one ICU with over 220 receptacles and seven circuits was found to have systems designed to handle loads only 46 percent higher than what was observed. An obstetrics unit at another facility, on the other hand, had systems that were oversized by 1,146 percent. 



Savage stopped short of saying he believes the results of the study should lead to changes to the NEC. “What the data shows is that there’s certainly large spare capacity between the required sizing per the NEC guidelines and the highest loads these systems ever see in a worst-case scenario,” he said. “But I would leave it to others to decide how much of a gap there should be.” 

Already, though, the NEC has been changed in recent years to reflect the shifting reality of increasingly efficient health care lighting. For the 2020 edition of the code, committee members cut the hospital lighting load calculation requirements by 20 percent, said Hannahs. “There have been major technical and energy advancements in recent years,” he said, “and this section hadn’t been modified since the 1970s.”

Additionally, NFPA 99, Health Care Facilities Code, has long recognized the large gap in what the NEC requires and what actual peak electrical demand in hospitals looks like. Specifically, the handbook for the code instructs users to size hospital generators based on the “actual demand rather than the connected load.” Sizing it based on NEC requirements often results in “generators that are very large relative to their actual demands,” the handbook says. “This oversizing can actually impair the reliability of the generators over time due to operation below minimum load levels.”

At the same time, Hannahs explained that “leaving adequate room within the electrical service” is critical not only for patient care during a pandemic, but also for other activities that may take place at hospitals, including renovations or other forms of construction. The study itself also notes that hospital administrator decisions, such as canceling elective procedures and diverting non-COVID patients to other sites, led to lower levels of energy use during the pandemic; a hospital that didn’t take such actions could in theory see higher energy use numbers.

Jeffrey Sargent, the NFPA staff liaison to the NEC, lauded both the quality and quantity of data gathered in the foundation report, and said it will be a valuable asset as committee members work on future editions of the code. “The pandemic has put many hospitals at near-full capacity for long durations of time, which, in an unfortunate irony, has been beneficial in accumulating real-time data under these taxing conditions,” Sargent said. “Armed with this information, the minimum NEC requirements for hospital loading could be adjusted, if necessary, to reflect the real-world data presented in this important project.”

If NEC requirements are further adjusted as a result of the foundation study and potential future research, Savage pointed to a number of benefits that could emerge, namely cost savings and energy efficiency. “As we look to build hospitals and health care facilities for the next generation, having this research will be really impactful down the line,” he said.

ANGELO VERZONI is associate editor of NFPA Journal. Follow him on Twitter @angelo_verzoni. Top photograph: GETTY IMAGES