Health care building electrical, lighting design model shifts
As hospitals and health care facilities evolve, the lighting, power and electrical systems within them must change
Hospital, health care insights
- Hospitals, health care facilities and related medical buildings require standby, emergency or backup power systems in nearly all cases.
- Resiliency is often at top-of-mind in discussion with hospital owners.
- Tanner Burke, PE, Senior Fire Protection Engineer, ACS Group, Austin, Texas
- Derek Cornell, Senior Associate, Certus Consulting Engineers, Dallas, Texas
- Beth Gorney, PE, Assistant Project Manager, Dewberry, Raleigh, North Carolina
- Sierra Spitulski, PE, LEED AP BD+C, Associate Principal/Studio Leader/Mechanical Engineer/Project Manager, P2S Inc., Long Beach, California
- Kristie Tiller, PE, LEED AP, Associate, Team Leader, Lockwood Andrews & Newnam Inc. (LAN), Dallas, Texas.
Describe any issues unique to designing electrical/power systems for these types of facilities.
Derek Cornell: The codes that govern emergency power systems for health care facilities are very prescriptive, dictated by multiple codes that are applicable within the same project. Items such as requirements for three separate emergency branches (life safety, critical and the equipment), strict wiring and separation requirements, as well as dictated receptacle quantities are specifically unique to health care facilities that are not applicable to other types of facilities.
Kristie Tiller: Reliability and redundancy are key factors in design. Some hospital systems are adding tertiary power systems based on renewable energy sources to reduce their carbon footprint and energy costs. Tertiary controls can take into account the system’s usage and capacity and use that information to reduce power losses.
What types of unusual standby, emergency or backup power systems have you specified for such facilities?
Kristie Tiller: Co-generation power is becoming more widely used. Several of our clients are using gas-fired turbines and heat recovery steam generators for the production of both electricity and steam for use in the chiller cycle. Overall system efficiency is good, utility costs go down and redundancy is achieved. In smaller, sometimes more rural installations where cost and total demand preclude the use of combined heat and power, we are seeing larger, conventional, diesel backup generators taking on larger portions of the facility. These facilities are moving away from providing only code mandated EPSS requirements and providing a more comprehensive system allowing the facility to operate “normally” during the event. The trend also requires the installation of larger and more robust fuel storage and delivery systems.
Derek Cornell: While not necessarily unusual, it does present its own set of unique challenges when connecting the HVAC cooling loads to emergency power within a health care facility. Hospitals are different from many other types of facilities in that there will likely be simultaneous heating and cooling peak loads due to the air change requirements that the mechanical designers must adhere to. There are not the same diversities that can be taken when dealing with these larger loads. It requires creativity and close coordination with the mechanical design team. On a recent project, we put a design in place to connect two 2,000-ton centrifugal chillers and their associated 250 horsepower primary chilled water pumps, cooling towers, condenser water pumps and controls to the EPSS. The hospital’s EPSS only has sufficient load to connect one of these chillers and associated equipment, but the system design allows for them to choose between one of two chillers providing that added level of redundancy.
In the aftermath of several recent severe weather events, owners of such projects are increasingly interested in electrical/power resiliency features. How are you meeting these demands?
Derek Cornell: Design for ultimate resiliency is at the forefront of early project discussions. We are working with one client that realizes that having a dual utility feed routed in entirely independent paths is no longer enough. We are working on upgrading their power to originate from two separate commercial substations located in separate geographical regions. That is just one example. Everyone has a heightened awareness of just how vulnerable this country’s infrastructure may be. We are being asked to design systems with more capacity, more on-site fuel storage, cooling on emergency power and more redundant equipment.
Kristie Tiller: In our recent projects for clients, it’s been mostly about hardening generator locations and distribution equipment and pathways. In our part of the country, Texas, flooding is the biggest threat. That means the first step is elevating equipment 20 to 25 feet above mean sea level. With our proximity to the Gulf of Mexico, hurricane force wind resistant structures are also required here.
What are some of the challenges when designing high-voltage power systems in hospitals, health care facilities and medical campus projects?
Kristie Tiller: The critical factor in dealing with medium-voltage distribution systems is the maintenance. The electrical staff must be trained specifically on 4,160 V equipment. It may be different from what they are used to using, which is 480 V gear. Some institutions choose to contract out the medium-voltage work to ensure the system is regularly maintained, which requires additional expense and management. Routine testing and certification of the system requires different equipment as well.
How does your team work with the architect, owner’s rep and other project team members so the electrical/power systems are flexible and sustainable?
Kristie Tiller: We work as a cohesive unit. We work with the owners to understand any future growth that may require additional electrical capacity. We collaborate with the architects and space planners to ensure we have the floor space to expand the electrical gear when needed. For some owners, the cost of downtime to its operation outweighs the cost of installing and having unused switchgear available for future expansion. This is often the case in areas like research laboratories. In these instances, we help the owners determine the best time-sensitive, cost-effective solutions and then work with the architects to make sure they are implemented.
Derek Cornell: To make sure that the electrical system design is flexible and sustainable we must understand the current and future goals of the user/owner. From the beginning of any project, we strive to create an atmosphere of teamwork and collaboration. Through this, we have open, sometimes hard conversations with the stakeholders about electrical system flexibility or even limitations. Understanding future growth plans of the facility allows for right-sizing equipment while working through a delicate balance of oversizing equipment that will support the longevity of the facility versus focusing solely on first cost.
When designing lighting systems for these types of structures, what design factors are being requested? Are there any particular technical advantages that are or need to be considered?
Derek Cornell: UV-C LED light fixture technology has really taken off in the lighting market as well as the use of Kenall Indigo-Clean fixtures, which use light in the 405 nm wavelength. Both types use the light fixtures themselves for disinfection. One project incorporated the UV-C technology into all of the housekeeping, soiled and clean utility and both staff and patient toilet rooms. Another project incorporated Indigo-Clean fixtures into the surgical lighting design of the operating rooms to provide continuous environmental disinfection. The Indigo-Clean light operates as the ambient (white) surgical lighting, mixing in a lower level of indigo (antimicrobial) light when the room is in use and then, using motion detection, can switch over to full indigo disinfection when room is unoccupied. The UV-C fixtures are designed to completely switch off the UV function upon sensing of occupant whereas the indigo simply reduces to a low-power mode such that at all times there is some level of antimicrobial environmental disinfection taking place within these spaces.