Hospitals, health care facilities’ power and electrical systems
Neal Boothe, exp Global Inc., Maitland, Fla.
David W. Crossey, Principal/Vice President, Lovorn Engineering Assocs. LLC, Pittsburgh
Jeff Harris, PE, LEED AP, Director of Mechanical Engineering, HGA Architects and Engineers, Minneapolis
Michael McLaughlin, Senior Vice President, Southland Industries, Washington, D.C.
Michael Sheerin, PE, LEED AP BD+C, Principal, Director of Health Care Engineering, TLC Engineering for Architecture, Orlando, Fla.
CSE: What’s the one factor most commonly overlooked in electrical systems in hospitals?
Boothe: Contractors specializing in health care construction understand the electrical systems requirements. With the economic downturn, commercial and residential contractors are entering the health care market. System requirements specific to health care often add significant cost and labor to their installations; contractors lacking health care expertise overlook and underbid projects as a result. One common issue is the lack of proper grounding and mechanical protection of branch circuits. Per NEC 517.13, all patient care areas must have one ground path provided by the raceway for the conductors and a second path by a dedicated grounding conductor for redundant grounding.
Harris: For people not typically involved in the design or operation of health care systems, the specific requirements of NEC 517 and 700, along with NFPA 110 and 99, often are overlooked. We often get to follow a project where the code requirements are not met, and the remodel project is burdened with bringing infrastructure up to code. This can result in sticker shock on what should be a fairly simple, low-cost remodel.
Sheerin: Proper arrangement and sequencing of the fire alarm system is a common issue that is overlooked or inadequately detailed. Also, hospitals purchase and select a lot of high-tech equipment, especially late in the completion of construction and fit-out of a project, so the challenges with ensuring that these systems are listed to work with the things they are connecting to, will actually work with those systems they are connecting to, and have the right electric power (emergency, UPS, etc.) are big headaches for us. In general, the electrical coordination of circuits and proper grounding is critical.
CSE: When designing standby or emergency power systems, what issues must you pay close attention to?
Harris: For existing structures (remodeling), we need to pay attention to the separation of existing electrical systems, along with NFPA 110 requirements. For new and existing buildings, we look at the selective coordination of the essential system. Also, there may be hospitals that want to have cooling systems on an optional system. There are complications that need to be addressed in this system, such as UPS for the temperature control system and chiller control panels to avoid computer hardware and software glitches that necessitate manual reboots. Also, there are considerations for simply locating the generators on a site, such as access to fuel delivery, wind drift of exhaust fumes toward air intakes on the building, providing good airflow through the generator room or enclosure, and local ordinances that restrict noise levels in the area or at adjacent property lines.
Boothe: Generator sizing is a common issue in the design of standby systems. The NEC provides very conservative requirements for the level of diversity that can be applied to most systems. As a result, the typical electrical system never runs near the calculated demand loads, giving the hospital excess capacity. Following these factors for a generator can lead to oversizing, and oversized generators run better under loads of at least 50% of their nameplate. Generators also experience more maintenance issues when very lightly loaded. Paralleling two or more smaller generators is often a better design solution.
Sheerin: The obvious ones are the intake and discharge airflow and making sure the exhaust doesn’t result in objectionable issues back at the hospital or a neighboring property. Noise control is very important and can really impact the size of the space, placement of equipment, and the extra cost measures needed to mitigate the real noise a generator creates. Also emission control requirements must be considered. From an electrical perspective, it is importance to consider paralleling the generators and distributing the emergency power in such a way that we are turning design planning into long-term success for the hospital. We must also determine the run time that suits the hospital’s needs, plus how much on-site fuel storage will be provided. A related issue to that is how to maintain that fuel oil from going bad, as can happen if it sits in a tank for too long. Being able to maintain the generator while it is running during an emergency has proven to be important by recent events, and we are very careful in how we specify these units to ensure the units are highly reliable and maintainable.
CSE: Share the story of a recent hospital project in which you incorporated renewable energy (PV, wind power, etc.).
Boothe: Camp Pendleton Naval Hospital’s base photovoltaics (PV) system is 148 kW, equating to approximately 625 PV modules on the site. PV will be installed on the new parking garage and over covered parking at the south lot. The systems will feed on-site generated energy directly into the adjacent buildings. The south lot will feed into the central plant distribution system and the garage-mounted PV will feed directly into the parking garage electrical system. Both PV plants will be configured to allow for future expansion. The PV plant will supply a renewable energy source sufficient to offset 35% of onsite lighting energy consumption.
Sheerin: We have looked at owner-purchased and third-party turnkey PV and renewable systems on numerous projects. Invariably, any capital committed to that objective is diverted to revenue-generating clinical investments. It has been tough. Have we had successes? We have been incorporating various air and waterside heat recovery systems and air handler condensate recovery systems for years in hospitals—they have a concise and quick ROI so owners quickly recognize the benefit.
CSE: When specifying lighting systems for highly specialized rooms (such as operating rooms), what challenges or cooling load issues have you faced?
Harris: Many operating room (OR) boom lights now use LEDs, which reduce but don’t eliminate the heat gain from the lights. Typical ORs have more equipment located in the OR that requires a higher electrical load (and heat gain) than the lights. As procedures have become high-tech and less invasive, the equipment required has increased, which is a major factor in the increase in the size of ORs. The result of this is more general lighting fixtures, more booms, more circuits, and a general increase in electrical load. Quite often we will design dual 5 kVA isolation panels, and occasionally dual 7.5 kVA isolation panels, and a 208-V laser panel, serving a single OR.
Sheerin: There are really no cooling load issues with the lighting systems today, primarily because of the highly efficient lamp types, whether fluorescent or LED. OR surgical lights are going LED and they appear to be great—the docs give positive feedback as it is less “hot” for them too.
The push for lower lighting power density (Watts per sq ft) has required a more careful study of lighting illumination levels to ensure that the quality of light isn’t inadvertently affected. This can make all the difference in the selection of the right light fixture for the application, and is really more impactful when you have 120 exam rooms than one specialty room.
Boothe: Lighting load is not a significant issue toward cooling in the operating room. More significant is the coordination of lighting design with many other devices located in and above the ceiling, including specialty surgical lighting fixtures, service booms, an array of supply air diffusers, fire sprinkler heads, speakers, and other ceiling-mounted booms for other surgical equipment. Much of this equipment requires additional structural support above the ceiling, which limits space available for the lighting fixtures. Coordination of all these devices and structural supports has become one of the most difficult aspects of designing the operating room.