Electrical modernization: A tale of two hospitals
Hospital electrical modernization requires that the design meets code and is flexible--and within budget.
We have a saying in our office: “Anyone can design a brand new hospital on a nice greenfield site. Where’s the challenge in that?”
Electrical designers and engineers face this challenge on virtually every hospital modernization project: how to engineer building systems that meet the current electrical loads and code requirements, are flexible enough to meet growing and changing hospital needs while at the same time meet budget constraints, and are constructible. It’s not glamorous work—in fact, it’s often taken for granted—but it’s an absolutely essential part of any hospital modernization project.
Investigation and analysis: the roadmap
Anyone who designs hospitals knows that new hospitals built on greenfield sites do not come along every day. Additions, expansions, and modernization projects are our bread and butter, the most common hospital design projects we encounter. The goal of these projects is usually to modernize the hospital in one way or another, whether to add a state-of-the-art catheter lab suite, expand the emergency department, add a new patient tower, or perform any of a hundred other possible upgrades, renovations, or expansions that happen every day in hospitals across the country. Many times the electrical systems and electrical infrastructure need some modernization and expansion to support these projects.
Any such project usually begins—or at least should begin—with the investigation and analysis phase. This is the phase where a team of engineers and designers investigates, confirms, and documents the hospital’s electrical infrastructure. “As-built” documents rarely are, so we need to verify all aspects of the electrical installation.
After verifying the existing infrastructure and analyzing the existing loads (12-month or 30-day recorded demand loads, times 125%, as required by the National Electrical Code (NEC) 220.87 , 2005 edition), we begin looking at every level of the electrical distribution system: the existing loads, the new anticipated loads, and the projected loads in five years. Code analysis also is an integral part of this phase, not a separate activity or action.
We must always keep an eye out for code deficiencies in the electrical systems. Just because we see a 600-amp breaker serving a 600-amp panel, we cannot assume there are actually 600 amps of wire in between the two. Or just because the existing drawings show two levels of ground fault protection on the main service (NEC 517.17) does not mean it was installed that way. We must verify it.
Some code deficiencies are obvious and jump right out at you—no life-safety branch in the hospital, or a fire alarm system without voice-evacuation capability in a high-rise building, for instance. Other code problems are more subtle, such as insufficient ampere interrupting capacity (AIC) ratings or lack of selective overcurrent device coordination. These require detailed calculations and studies to determine if there is a problem. This is all part of the investigation and analysis phase, which is critical before any hospital electrical systems modernization project can begin.
Frederick Memorial Hospital in Frederick, Md., is a large regional hospital with a modern central energy plant and reliable, flexible electrical infrastructure. But in 1998 it was a smaller facility with piecemeal electrical distribution. Like many hospitals, it had a combination of obsolete electrical equipment, aging equipment, and relatively new distribution equipment. In 1998, Frederick Memorial Hospital began a multiyear, multiphased project (originally called Project 2000) that was completed in 2006.
The project began with a detailed investigation, analysis, and recommendations report. A team of engineers and designers spent more than three months to complete the report, which ultimately filled a 4-in.-thick, three-ring binder. The report analyzed every electrical system in the hospital, from normal and emergency electrical distribution, to nurse call and fire alarm, to voice-data and security systems.
The report’s recommendations were accepted by the hospital and became the electrical systems roadmap for each of the phases. The recommendations for modernizing the hospital’s electrical systems and supporting the six phases of the project included:
Expanding the central energy plant
Upgrading the electrical service
Replacing the existing emergency generators and transfer switches
Cleaning up existing electrical equipment and correcting code deficiencies
Expanding the existing head-end fire alarm system
Expanding the existing sub-basement and tunnel system to distribute electrical systems across the campus.
The renovation: an opportunity to clean up
All too often in many hospital expansion and modernization projects, the natural tendency of electrical design engineers is to avoid older or non-code-compliant electrical infrastructure and equipment. It is often easier to install new equipment to serve the new project area, but sometimes the best solution for the hospital is to clean up existing distribution equipment or systems that are not in compliance with NEC-517. This might involve removing noncomplying loads (recircuiting the soda vending machine from a life-safety panel to normal), refeeding a panel with a properly sized feeder, or replacing 10,000 AIC breakers in a 35,000 AIC panel. Upgrading older or noncompliant equipment also can help save space in the hospital by reducing the area needed for redundant electrical equipment. It also can save money.
At Frederick Memorial Hospital, since the six phases of the project touched nearly every piece of the hospital, simply avoiding existing electrical infrastructure was not an option. Replacing all of the existing distribution with brand-new equipment was not possible either, due to obvious budget, phasing, and operational constraints. So a holistic approach was developed:
New head-end equipment to meet capacity, flexibility, and reliability needs
Removal of extremely old and malfunctioning equipment
Cleaning up of existing electrical distribution wherever possible.
Cleaning up of equipment consisted of ensuring that electrical loads were on the proper branch of the distribution system. For example, several distribution panels were a mix of critical and equipment loads, or a mix of critical and life-safety loads. In most cases, it was simply a matter of moving one or two loads from one distribution panel to another to achieve strict code compliance. Some panels were simply re-fed to the proper branch.
Cleaning up also included seemingly simple things, like providing new typed panel schedules, providing proper breaker labeling, and providing color-coded, engraved nameplates for panels that clearly identified the panel’s name, branch of power, voltage, and where it is fed from. These simple items go a long way to creating and maintaining clean, code-compliant distribution branches.
The big addition: an opportunity to modernize
The Mayo Clinic in Jacksonville, Fla., expanded its two-story clinic building into a six-story, 500,000-sq-ft, 214-bed hospital by adding three floors of diagnostic and treatment space, a mechanical penthouse, and a six-story patient tower. This project posed several electrical design challenges. There was an obvious need to increase service and distribution capacity. (We could not serve 500,000 sq ft of hospital from an infrastructure sized for 100,000 sq ft of clinic.) The new patient tower was going to be located on top of the underground campus loops for utility power, emergency power, and communications.
The hospital is located only three miles inland from the Atlantic coast, in hurricane-prone Florida. The solution: modernize the normal and emergency electrical distribution systems, provide protection for the electrical equipment from potential hurricane flooding, and keep the existing clinic and campus operational by locating the new normal and emergency infrastructure on the sixth floor of the new patient tower, and use it to backfeed the clinic’s electrical systems. The new services included four normal substations, four emergency substations, and eight automatic transfer switches. Locating the equipment above the flood plain in the new portion of the building would protect the electrical system from flooding, but also allow the clinic to remain operational with only minimal downtime during the equipment switchover.
Many multistory hospital modernization projects are made more challenging due to the lack of life-safety and equipment branch panels, especially 120/208 V panels, convenient to the renovation areas. Electrical engineers try to save money during new construction projects by limiting the number of these panels by running these circuits to panels on other floors, which is permitted by the American Institute of Architects’ Guidelines for Design and Construction of Healthcare Facilities for life-safety branch panels, but not for equipment branch panels, or in remote areas.
Looking at the lifetime costs of construction, it often is easier and better design to simply provide life-safety and equipment branch panels on every floor or in each major area of the hospital. One argument against doing this is that there are not enough loads to justify providing these panels. But there most likely are: 120/208 V life-safety loads include fire alarm panels and medical gas alarm panels (not soda machines), and equipment branch loads often include mechanical accessories, control circuits, direct digital control panels, damper and box power and controls, etc.
So include a 120/208 V life-safety and equipment branch riser system in your next new hospital project, or use a large expansion project as an opportunity to modernize and upgrade the life-safety and equipment branch systems. You will be helping the hospital in the long run.
At the Mayo Clinic, the new patient tower was designed with equipment and life-safety distribution (as well as normal and critical) on each floor and in each major area of the hospital. This feature simplifies future renovation projects and provides the hospital with greater flexibility to add and correctly circuit loads of any type in the future.
Central energy plant: the heart of the modernization project
The Mayo Clinic project was one piece, albeit a very big piece, in an overall campus master plan. The engineering infrastructure master plan was the campus’s 20-year master plan, with particular focus on the next five years of planned construction, which included the new hospital. Engineers quickly determined that the key to upgrading and modernizing the campus’s electrical infrastructure to meet the growing needs of the campus was a modernized, hurricane-hardened central utility plant (CUP). The existing CUP was not designed nor constructed to withstand hurricane force winds or flooding. The new CUP, designated as CUP B, and the emergency electrical distribution equipment inside were designed to serve the new hospital and a new office building, and to backfeed the campus’s medium-voltage underground emergency distribution loop that provided emergency power to most of the buildings on the campus. The new CUP B also was designed in strict compliance with NFPA 110, and can expand in the future to keep up with the growing infrastructure needs of the campus, which is essential for any electrical modernization project.
With the ability to house up to nine 1500-kW engine generators, the new CUP-B was hurricane hardened to withstand up to a Category 5 hurricane and elevated to above the flood plain. The initial phases included two 1500-kW engine generators (and paralleling switchgear) to backfeed the campus’s underground medium voltage emergency loop. The next phase of the CUP B expansion included three additional 1500-kW engine generators, for a total of 7.5 MW, to the capacity of the campus emergency system to serve the new hospital loads. These five diesel-powered engine-generators are served by four 20,000-gallon fuel storage tanks that provide the system with approximately five days’ worth of fuel. The engine-generators located in the existing CUP A remained in place and were used to serve existing chillers and cooling equipment in CUP A, further modernizing the campus by providing cooling capacity on emergency power. In one fell swoop, this electrical modernization project dramatically improved the reliability and capacity of the campus’s emergency power systems, and the hospital’s ability to remain operational during an extended normal power outage.
The central energy plant expansion at Frederick Memorial Hospital included upgrades to and replacement of the normal distribution system, which originally consisted of three switchboards of varying ages and states of disrepair. During the investigation and analysis phase, engineers determined that the plant would be expanded and three new electrical services would be added: a new 4,000-amp, double-ended switchboard to serve the hospital and a new 4,000-amp switchboard to serve all of the central plant loads. The old switchboards and services were removed. Although not the cheapest first-cost solution, this option solved numerous code, capacity, reliability, and phasing (down-time) concerns.
A similar analysis led to a similar solution for Frederick Memorial’s emergency power systems. The central plant would be expanded, and two new 1250-kW diesel engine generators, paralleling gear, and new bypass isolation transfer switches would replace two old generators and undersized transfer switches. Again, NFPA 99, NFPA 110, and NEC-517 code issues, capacity needs, and phasing considerations—not to mention maintainability and reliability—were the drivers over first cost.
So with all due respect to brand-new hospitals on greenfield sites, give me a messy hospital renovation project that requires electrical infrastructure modernization any day.
Testing equipment via electrical commissioning
Commissioning is one of the new buzz words in the AEC industry. When most people hear the word “commissioning,” they immediately think of mechanical equipment. But commissioning of electrical systems is nothing new to many hospital design engineers. Commissioning of electrical systems should be an integral part of any hospital project but especially of a renovation, expansion, or modernization project where new electrical equipment and system components are connected and intertwined with existing equipment. Proper electrical commissioning will confirm that these systems function properly.
Ensuring that electrical infrastructure is functioning properly, the way it is intended to, is essential to the safety of both patients and hospital staff. Typical electrical systems that are commissioned include emergency power systems (generators, paralleling gear, transfer switches, and fuel systems), grounding and equipotential grounding, fire alarm systems (including air-handler shut-down), and nurse call systems. All phases of the commissioning process, but especially the functional testing phase, should include hospital operations and maintenance personnel, and a formal commissioning report. This assures that the operations staff, who ultimately will be responsible for operating and maintaining these systems, understand how the systems were designed and how they are intended to operate. It also assures staff that everything is properly documented.
Tunneling to success
In the case of Frederick Memorial Hospital’s expansion and renovation project, the capacity and code compliance of the front end normal and emergency electrical distribution was not the only challenge. Another challenge was how to get major electrical feeders from the central energy plant to almost every corner of the campus. The existing hospital already had a limited sub-basement and tunnel system that was used to distribute feeders. The natural solution was to expand this concept and employ a system of tunnels to reach (or at least get close to) each of the major renovation and expansion areas. Although there was an increased first cost for constructing these tunnels, it was comparable to the cost of trying to route multiple conduits for multiple branches of power through the crowded ceiling space of existing, occupied areas of the hospital to reach the expansion areas. Plus, the tunnels allowed for flexibility to easily add infrastructure in the future, and for access and maintenance.
|Gelfo is principal and division director with TLC Engineering for Architecture|
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